Category Archives: Tips & Tricks

How the EventSentry SysAdmin Tools Focus on File System Maintenance

EventSentry SysAdmin ToolsOver the past couple months, we’ve taken time to go through the various EventSentry SysAdmin Tools, one by one, and show you how they can benefit your environment in powerful ways. We’ve talked about the security tools, the networking tools, and the “check” monitoring utilities. As you know, the SysAdmin Tools offer a set of graphical and command-line utilities designed to help you with your daily administrative tasks. These tools are always being honed to provide simple yet powerful functionality.

This month, let’s take a look at the extremely beneficial file-system utilities: ADSList, CheckSum, DirMon, DirectorySize, FileReplace, PurgeTemp, and SuperDel. Here’s what they can do.

ADSList
ADSList scans a folder structure to find any alternate data streams (aka “hidden” data streams). Alternate date streams are a feature of the NTFS file system in which you can hide payload (additional files) inside existing files. The jury is still out about whether malware uses these streams, but it’s always a good idea to make sure nobody has hidden something malicious in alternate data streams, because the Windows Explorer and directory listings don’t show them.

ADSList lists any alternate data streams that are associated with a file. When the tool finds an alternate data stream, it displays the name of the stream along with the regular file the stream is associated with. The output will also show a summary that lists the number of files analyzed, the number of files that have an alternate data stream associated with them, the number of alternate data streams that have been found, and the elapsed time.

The main purpose of ADSList is to give you a command-line utility that can be run/scheduled on a regular basis to reveal any hidden streams on a server or workstation. The /s option lets you include subdirectories.

CheckSum
CheckSum generates a one-way checksum (error detection scheme) of a file with a configurable algorithm and displays it onscreen. This capability is useful for ensuring the integrity of a file and making sure that it hasn’t been modified. CheckSum not only supports the SHA set of cryptographic hash functions (e.g., SHA256, SHA512), but also less secure hash functions (e.g., MD5).

To display and create a file’s checksum, simply supply the filename as the first argument. Keep in mind that generating checksums of large files (e.g., greater than 100Mb) can take a significant amount of time and CPU time.

The CheckSum utility is also included in EventSentry as an add-on to the File Monitoring feature, which can automatically generate SHA checksums and detect file modifications based on checksum changes.

DirMon
Directory Monitor (DirMon) is a useful troubleshooting tool that monitors a directory (and optionally subdirectories) and displays all file changes in real-time. You simply run it on the command line, and it displays any file activity occurring on a given folder (or subfolder).

DirMon will show you when files are added, deleted, or modified. DirMon also lets you specifically include or exclude filters, so you can skip files that you aren’t interested in or show only files that you are interested in. The /I (/includefiles) option includes only files that match a wildcard filter, and the /e (/exclude) option does the opposite. The /s (/subdirectories) option includes subdirectories.

DirectorySize
The DirectorySize (dirsize.exe) utility calculates the current size of a directory, including subdirectories, and displays it onscreen. The output shows the number of files and directories searched, and the total size in physical (actual size taken up on the disk) and logical (actual file size) bytes.

DirectorySize will process the current directory if you pass no command-line arguments.

PurgeTemp
PurgeTemp is a new and exciting tool that lets you purge files that are older than a certain number of days. The tool traverses the %TEMP% directory (or a manually specified directory) and deletes files that have not been modified in 120 days (by default). Because it scans the temp folder by default, you can incorporate PurgeTemp into a login script or run it with Task Scheduler to clean up temp files, for example. It’s a great way to keep users’ temp folders small.

You can customize and configure all of PurgeTemp’s parameters, including /t (time in days) and /p (path). When called without arguments, PurgeTemp simply shows the configured temp directory, the number of files in the directory, and their cumulative size.

SuperDelete
SuperDelete (superdel.exe) essentially deletes all instances of a specific file. It parses a directory (including subdirectories) and deletes multiple occurrences of one file.

Suppose you have a thumbs.db file that Windows Explorer creates in every folder containing images, and you want to remove that from every folder on a drive. You can use SuperDelete for that purpose, using the <directory> variable to specify the directory to search (subdirectories are included), and the <fileToDelete> variable to find all occurrences of a file in the directory (wildcards are supported).

FileReplace
FileReplace is a command-line utility that parses a directory (including subdirectories) and replaces multiple occurrences of one template file with a template file of the same name.

Suppose you have 50 instances of various myfile.txt files scattered on your computer. You can quickly replace them all with a new myfile.txt file.

Another useful example is this: You have file C:\WebSite\Default\index.html and want to replace all other index.html files in the directory D:\WWW (including subdirectories) with C:\WebSite\Default\index.html. FileReplace lets you accomplish that with one command.

Streamline Your File System!

This is just another taste of the free, constantly evolving tools available in EventSentry SysAdmin Tools. Give them a try—they’re all free and will help you manage your IT infrastructure more effectively.

The “Check” Monitoring Utilities of the EventSentry SysAdmin Tools

EventSentry SysAdmin ToolsLast week, we talked about the security-focused utilities of the freeware EventSentry SysAdmin Tools, part of the larger EventSentry network-management solution. The SysAdmin Tools offer a set of graphical and command-line utilities designed to help you with your daily administrative tasks. These tools are constantly under development, always being honed to provide simple yet powerful functionality. Three of these tools are vital monitoring utilities: CheckDB, CheckTCP, and CheckURL. Here’s what they can do.

CheckDB verifies a database connection through the Open Database Connectivity (ODBC) interface. With this capability, you can not only verify that a database server is up and running, you can also check that a database is online. checkdbYou can optionally run a SQL statement of your choice. CheckDB is particularly useful because it doesn’t merely verify that a database server is online (e.g. through a port check), it also verifies that a SQL statement was successful. That capability improves the usability of this tool because it verifies that the SQL server is accepting logins and is working correctly (at least as far as that statement is concerned). Also, this tool will work with any database that supplies ODBC drivers, so it will work with MySQL, MSSQL, and so on. You can schedule CheckDB from within EventSentry (“Application Scheduler”), and even time it. The scheduling capability is a bit advanced, and the setup requires a few steps, but after getting it up and running, you can easily schedule a statement and configure it to notify you if it takes more than two seconds, for example. The parameters of this command-line utility are straightforward: The <DSN/Connectionstring> parameter is the DSN or connection strong to connect to; the /q (or /query) parameter is the SQL query you can run upon successful connection; the /u (or /username) parameter is the DSN unsername to connect as; and the /p (or /password) parameter is the password for “username.” CheckDB can log output either to the console or to the event log, making it easy to receive alerts from the utility through EventSentry or any other log monitoring software. The /I (/logToLog) and /c (/logToConsole) parameters take care of this functionality.

CheckTCP is another command-line application, this one letting you quickly determine whether a TCP port on a host is open. Additionally, you can receive initial data sent from the remote host through an open TCP connection, such as when connecting to most SMTP hosts. CheckTCP exists because Windows doesn’t really offer a built-in way to check whether a TCP port is open. Yes, Nmap is a powerful utility, but you probably often just want to know whether a server that you rebooted is available for remote desktop login. checktcpFor that, you can simply run “checktcp server123 3389.” It’s not fancy, but it accomplishes a vital task. If you use the /s switch, you can get only the first line of the response. For example, if you use it against a mail server, you would get this:

checktcp /s mymailserver 25
Data: 220 mx.somedomain.com Microsoft ESMTP MAIL Service ready at Fri, 25 Apr 2014 15:07:33 -0500

The parameters of this command-line utility are straightforward: The /s parameter, as mentioned, gets initial data from the remote port (for example, when connecting to an SMTP port); the <Port> parameter displays the TCP port to connect to; and <Hostname> identifies the IP address of hostname to connect to. Although you can use this utility to display any data sent by the remote host over the established connection, CheckTCP is not intended to be used as a port scanner.

CheckURL is the HTTP version of CheckDB, and it lets you detect changes in web pages (through checksums) and look for text inside web pages. With CheckURL you’ll know when a web page changes or when a particular string is or isn’t included in a page. You might use this tool to monitor your corporate pages (at least those which are static and don’t have dynamic content) and also development pages to ensure that they don’t return a HTTP error. This is beneficial because you can have CheckURL look for specific text on the pages. The checksum feature is cool, too, because it lets you know when a page changes. As with with CheckDB, you can schedule CheckURL from within EventSentry (“Application Scheduler”), and even time it.checkurl The scheduling capability is a bit advanced, and the setup requires a few steps, but after getting it up and running, you can easily schedule a statement and configure it to notify you if it takes more than two seconds, for example. At  NETIKUS.NET, we monitor our online store that way. If the store takes more than three seconds to load, we get an alert. Like CheckDB, CheckURL can log output either to the console or to the event log, making it easy to receive alerts from the utility through EventSentry or any other log monitoring software. CheckURL supports SSL as well as proxy servers.

More to Come!
This is just a taste of the free, constantly evolving tools available in EventSentry SysAdmin Tools. Give them a try—you won’t be able to stop with just one.

The Essential Security Tools of the EventSentry SysAdmin Tools

toolsPart of our larger EventSentry network-management solution, the freeware EventSentry SysAdmin Tools offer a set of graphical and command-line utilities designed to help you with your daily administrative tasks. These tools are constantly under development, always being honed to provide simple yet powerful functionality. Three of these tools are vital security utilities: Password Assistant, Service Secure, and Task Secure. Let’s take a look at what they offer.

Password Assistant
Password Assistant is a simple yet powerful tool that lets you update the passwords of user accounts on multiple Windows machines. You simply enter the username, the old password, and the new password (with confirmation); after doing so, you can select the computer name(s) from a network neighborhood list (with a filter option) or choose the computer(s) from a text file. The update process can also be logged to a text file.
All the parampassword_assistanteters of the command-line utility are provided in clear terms: The /u (or /username) parameter specifies the username whose password needs to be changes, the /pwold parameter takes that account’s old password, and the /pwnew parameter accepts the new password; there are also /n (or /network), /f (or /filepath), and /filter parameters for specifying computers, as mentioned above. The /ignore_rest parameter ignores the rest of the labeled arguments following this flag, and the /version parameter displays version information and exits.
A great sample use of Password Assistant is when you need to update the administrator passwords on all of the workstations in your environment. Password Assistant provides a one-stop interface—or a simple command-line utility—for making the task hassle-free.

ServiceSecure
Service Secure provides a simple command interface that displays all of your system’s services, grouped by service account. The tool also lets you easily reset service passwords by specifying username and password rather than having to manually configure those services through the Microsoft Management Console (MMC).srvsec_1
All the parameters of the command-line utility are provided in clear terms: The /p (or /password) parameter sets a password; the /c (or /changepwd) parameter changes a password; the /r (or /restart) parameter restarts the service after the password has been changed; the /u (or /username) parameter lists only those services running under a certain username; the /ignore_rest parameter ignores the rest of the labeled arguments following this flag; the /version parameter displays version information and exits.
Suppose service security has been compromised, and you need to quickly change the passwords of a user account used by a number of services. That task is no longer a logistical nightmare: You can now simply use ServiceSecure in a batch file and update all affected services in your entire network in a matter of moments.

TaskSecure
Task Secure provides a simple command interface that displays all of your system’s scheduled tasks, grouped by task account. The tool also lets you easily manage the passwords stored in scheduled tasks on your network. Simply specify the username and password, and Task Secure will reset the password stored in all scheduled tasks (using the specified username) on the specified computer (local or remote).

TaskSecureAll the parameters of the command-line utility are provided in clear terms: The /r (or /remote_host) parameter lists all the scheduled tasks on a given host; the /u (or /username) parameter lists only those scheduled tasks running under a certain username; the /p (or /password) parameter sets a password for every scheduled task configured for a certain user account; the /ignore_rest parameter ignores the rest of the labeled arguments following this flag; the /version parameter displays version information and exits.
Suppose you need to quickly change the passwords of all the scheduled tasks used by one user. You can now simply use Task Secure in a batch file and update all scheduled tasks in your entire network in a matter of moments.

More to Come!
This is just a taste of the free, constantly evolving tools available in EventSentry SysAdmin Tools. Give them a try—you won’t be able to stop with just one.

Automatically Restarting a Failed Windows Process

Whether it’s a critical process running on a server or an application on your desktop – sometimes processes terminate and need to be restarted – immediately.

With EventSentry & EventSentry Light you can do just that: Automatically restart processes immediately after they terminate.

In the past, one drawback of EventSentry launching a process was the side effect that any process started by the EventSentry agent would run under the same account as the EventSentry agent itself (usually a privileged domain account or LocalSystem).

In this post I’ll discuss how you can work around that limitation in a secure manner using a scheduled task. When the critical process fails, instead of launching the process directly through a process action, EventSentry will trigger a scheduled task instead. Why? Because scheduled tasks allow you to configure under which user a task will run – and the user’s password is securely stored in Windows.

The recipe for accomplishing this feat is as follows:

  • Process Monitoring monitors the process
  • An event log filter looks for the “failed process” event and triggers a process action
  • The process action starts a scheduled task

Let’s look at this in detail. First, on the host where the critical but unstable task is running, you create a schedule task in the Windows “Task Scheduler”. Under General, give the task a descriptive name (“Start Super Important App”) and change the user under which the program should be running under. In most cases you will also want to make sure that you configure the task to run whether a user is logged on or not. Then, under “Actions”, add a new action “Start a program” which points to the executable that should be launched. After you click “OK” you will be prompted for the password for the user.

Scheduled Task

Creating a scheduled task

The next step is to setup process monitoring in EventSentry. Right-click “System Health” and create a new package and assign it to the computer(s) in question. Right-click the newly added package and select “Add – Processes”. Click the newly added object and add the name of the process which should be monitored. You can configure how many instances of the processes are required, and with which severity the event will be logged when the process is inactive.

process monitoring

Configuring process monitoring

Now we create a new “Process” action. Right-click the “Actions” container, select “Add” and enter a descriptive name (e.g. “Trigger Super Important App”). In the Filename field specify:

%SYSTEMROOT%\system32\schtasks.exe

And for the Command Line Arguments enter:

/Run /TN “Start Super Important App”

This uses the built-in Microsoft utility schtasks.exe to run the task we created in our first step. At this point EventSentry will monitor the specified process and log an event if the process is inactive. And while we do have an action to trigger the scheduled task, we still need to tell EventSentry when to launch that action.

EventSentry Process Action

Configuring a process action to start a scheduled task

For the next step, right-click the “Event Logs” container, select “Add Package” and give that package a descriptive name. Then assign the package to the same host. Right-click the newly added package and add a filter by clicking “Add Filter”. In the filter dialog, add the “ Trigger Super Important App” action to the action list and configure the following fields:

Event Log Include Filter Rule

Setting up a rule to trigger the process action

Event Severity: Information
Event Log: Application
Event Source: EventSentry
Category: Process Monitoring
Event ID: 10401
Content Filter (wildcard): *critical_app.exe*

Important Notes: The event severity will need to match whichever severity you selected when adding the process monitoring object in the system health package. The content filter can also be configured to match insertion string #1, in which case the wildcards are not necessary.

And that’s all there’s to it, simply save the configuration when you are done. If the process is running on a remote host then don’t forget to push the configuration to that host.

CryptoLocker Defense for Sysadmins

It seems as if CryptoLocker has been making the rounds lately, much to the dismay of users who don’t have working backups of their precious office documents.

While I admire Cryptolocker’s simplicity and effectiveness from a purely technical and entrepreneurial standpoint, what the software is doing does appears to be illegal in most countries and so I’d like to offer some advise on how to tame the beast. If you’re looking for a 5-minute fix then I have bad news: implementing the CryptoLocker defense I have outlined below, while completely free, will take a little more than 5 minutes to implement. But knowing that you have an effective defense against CryptoLocker may very well be worth it. After all, CryptoLocker seems to find its way into a lot private networks these days.

CryptoLocker Screenshot

The ideas set forth in this blog post apply mostly to Windows-networks with file servers, but could be adapted for individual computers as well (though this is not covered here – let me know if you’d like me to include this scenario).

About CryptoLocker
For those who have not heard of CryptoLocker yet, it is a piece of software which encrypts pretty much all common office-type documents, including Microsoft Office, AutoCAD, PDFs, images and more. This blog article from MalwareBytes has a complete list of extensions. Once encrypted, CryptoLocker charges you to decrypt (your own files) again. It’s public key cryptography gone wrong; I wonder if Diffie & Hellman saw this one coming. And to make the whole spiel even more interesting, you only get a limited amount of time to pay before your files will remain encrypted. Forever. Oh – and the longer the wait, the more you have to pay. And with recent bit coin exchange rates in excess of USD 1000, the amount that needs to be paid can be uncomfortably high.

It is pretty difficult to defend against something like CryptoLocker other than through usual means of AntiSpyware software, user eduction and strict policies against opening and downloading files from the Internet, email attachments and such. In most cases CryptoLocker comes in form of a ZIP attachment disguised with a PDF icon.

One reason CryptoLocker is so effective – yet difficult to block – is because it exhibits the same behavior as users would: It “simply” accesses and modifies files like a user would. And infecting a machine isn’t all that difficult since CryptoLocker doesn’t require any elevated permissions to run. On the contrary, it wants to run in the same context the user does, so that it can access and see the same files a user does. As such, security features like UAC are utterly useless against ransomware like CryptoLocker – it’s a whole new type of software.

Backups
The most effective defense against CryptoLocker is to have a working, tested backup. Let me repeat this: A WORKING and TESTED backup. Users have lost all their data because they thought that they had a backup in place when their backup was broken in some way.

We’ve seen posts of users who deleted all the files CryptoLocker encrypted, thinking they had a working backup. They had a backup, but it was apparently not recently tested and as a result the user lost all of their data.

Naturally, CryptoLocker does not like backups. It dislikes them so much that when CryptoLocker runs, it even tries to delete any Windows Shadow Copy backups. Cloud backup services (including Dropbox, Skydrive and Google Drive etc.) which keep versions of your files offer some protection, but restoring older versions of your files may be a tedious process.

The Defense
The most obvious defense against CryptoLocker is AntiSpyware software, e.g. MalwareBytes. Most AntiSpyware & AntiVirus software still uses signatures however, so new versions of the ransom ware often remain undetected at least for a few days.

So instead of detecting CryptoLocker itself, we can sniff its tracks so to speak. CryptoLocker’s predictable behavior can be used against it. CryptoLocker’s objective is of course to encrypt and hold hostage as many files as possible, so to increase the likelihood of the user purchasing the decryption key from the thugs.

And it is that very pattern that we will try to exploit and use as a trigger to detect and take corrective measures. The approach consists of measuring how many files are being changed in a certain time interval, and if a certain threshold is being exceeded (say more than 10 files modified in 1 minute) we assume that CryptoLocker found its way into our castle. Even though users modify their documents on a regular basis, users can usually make only so many changes at a time and most likely at a much slower rate than any sort of script / software would.

Another approach would be to create one or more honeypot or canary files, which we know (or hope) a user would not modify. If a checksum change in one of those files were detected, we could (more or less) safely assume that CryptoLocker was on one of his rampages again and take corrective measures. The honeypot file would have to be modifiable by users (otherwise CryptoLocker would also not be able to modify it), which makes accidental modifications by users possible (although somewhat unlikely).

This 2nd approach isn’t quite as solid in my opinion, since CryptoLocker is most certainly adapting to changes, and may skip files that it may suspect are a trap. For example, it could skip small files or skip directories with a very small number of files and so forth.

A more sophisticated approach, where we detect an unusually large number of files changes in a small time period, is going to be harder to circumvent by CryptoLocker. The good news is that we have a free (it’s really free, not a trial) software tool available which can do just that. It can:

  • detect file changes
  • measure the rate of file changes (through event log alerts)
  • stop/start services or launch processes
  • send out alerts

EventSentry (Light) to the rescue
EventSentry Light is the free version of our full-spectrum monitoring & compliance solution EventSentry. The features we can utilize to come up with a defense are:

  • File Checksum Changes (part of System Health Monitoring)
  • Filter Thresholds (part of Event Log Monitoring)
  • Action (control services, send out emails)

File Checksum Monitoring
Monitors any folder and detects file size changes, checksum changes and file additions and deletions. EventSentry Light will log file checksum changes to the event log (it’s big brother can also log them to a database), which in turn is monitored by the real-time event log monitoring component.

Event Log Monitoring & Thresholds
This component supports a variety of sophisticated features, one of which are thresholds. The thresholds feature lets you essentially detect event log entries that occur at a certain pace. For example, if 10 specific events occur in 1 minute then let me know and/or take corrective action.

Service Action, Email Action
EventSentry supports a variety of action types to be triggered when an event occurs, with email usually being the most commonly used one. You can also control services, use REST APIs, launch processes and much more. We’ll use the former to stop the file sharing services (LanmanServer) when we have determined that CryptoLocker is on the loose.

I will go into step-by-step instructions on how to configure EventSentry at the end of the post.

The Baseline
The most difficult thing to determine is the maximum rate of file changes we deem normal, as we need to have a baseline in order to configure the threshold slightly above that. This number will vary from network to network, with file servers serving lots of users obviously requiring a larger threshold. I’d like to repeat that determining the right threshold is very important. If it is too low, then normal user activity will trigger an alarm; if it is too high then the alarm may never be triggered and CryptoLocker won’t be caught in time.

The best approach is to setup file monitoring and let it do its job for 1-2 days to determine a baseline. Once the baseline is established, we can increase it by a certain factor (say 1.5) and use that as the threshold.

Setting up the trap requires 3 steps. In this case we assume that EventSentry is either installed directly on the file server, or an agent is deployed on the file server (in which case you will need to make sure that configuration updates are pushed to the file server(s) in question).

Step 1: Monitoring the directory/ies
In EventSentry, right-click the system health packages and add a new package. Right-click the package, select “assign” and assign it to all file servers. Right-click the package again and add a “File Monitoring” package. Click the new object. Directories are monitored in real time by default, but EventSentry requires a recurring scan as well – in case Windows doesn’t send real time notifications. This is usually a good thing, but when you are monitoring large directories it’s best to set the interval very high (future versions will allow for this to be unchecked).

File Checksum Monitoring Settings

In the package, add all the folders which should be monitored and only check the “checksum change” check box. Do not check any of the other check boxes in the bottom left section at this time. Since we haven’t established a baseline yet, we’ll set the severity of the event log alerts to “Information”. If the monitored folders contain a lot of non-Office files then it may be a good idea to adjust monitoring so that only office files (e.g. .doc, .xls, etc.) are monitored. If you prefer to monitor all files, simply change the setting to the green PLUS icon and make sure the list of exclusions is empty (or specifies files that should be excluded, e.g. *.tmp). Below is a screenshot of how this can be configured.

File Checksum Monitoring Settings

When you save the configuration, EventSentry will enumerate all files in the folder and create an initial checksum for every file. The agent will log event 12215 when the scan starts, and event 12216 when the scan is complete. When that happens, EventSentry is essentially “armed” and will detect, and log, all checksum changes to any of the files in the monitored directories.

At this point we’ll want to let this run for at least 24 hours during a “normal” work day, as to determine how many file changes occur on average. You are going to be at a bit of an advantage if you are running the full or the trial version with database support, as it will be a lot easier to determine the number of file changes occurring through the web-based reporting.

Step 2: Setting up the trap
Now that we have established a baseline, we’re ready to setup a threshold. This time we’ll create a new event log monitoring package. Right-click “Event Log Packages” and add a new package and call it “CryptoLocker Rules”. Like before, assign it to the file servers we are monitoring. Right-click the package again and add a new event log filter. Configure the filter as shown in the screenshot below. Note that we are triggering an email action for now. The content filter can be used to restrict the filter further, e.g. to only match certain directories if you are monitoring several directories with EventSentry.

Event Log Filter Setup

Now things are getting interesting. The goal is to create an error event in the event log when X amount of file checksum changes occur in a given time period. To get there, we’ll start with the “General” tab where we tell the filter what type of event we are interested in (see below). Once that event is defined, we’ll move on to the “Threshold” tab which is where we specify the threshold parameters. For the purpose of an example, let’s assume that we have established a baseline of 100 file checksum changes per day, with a work day starting at 8am and ending at 7pm. Assuming that activity is somewhat spread throughout the day, this amounts to about 9 file changes per hour. Naturally we’ll have to assume that file changes aren’t always evenly spread out throughout the day, but setting up a “if 20 checksum changes occur in 1 minute shut file sharing down” is probably a reasonable threshold. Configure the threshold as shown in the screenshot below, with whichever threshold you came up with.

Event Log Filter Threshold Setup

Step 3: Triggering corrective action
When our threshold is reached, EventSentry will log an error to the event log with event id 10601 and trigger the specified action(s) from the “General” tab (Default Email) one time per threshold interval.

At this point we would merely receive an alert when we suspect that CryptoLocker is at it again. If you are cautious then you can retain this setup for a little while (e.g. a day or two) to ensure that you are not getting any alerts about the threshold being met (assuming that CryptoLocker is not active on your network in which case you should get the emails).

To go all in and trigger a server service shutdown, we’ll need to create a service action now. On Windows, file sharing services are provided by the “Server” service, which uses the internal name of “LanmanServer”. The service action allows you to control any service (start/stop/restart), and in this case we’ll obviously want to stop the server service, so that clients cannot access the file shares on your server anymore. We’ll trigger an email action at the same time of course, so that the sysadmin in charge is aware of what is going on. While shutting down all file services seems a bit extreme, it’s unfortunately the most effective way to prevent more files from becoming encrypted.

So for the next step, right-click the “Actions” container and select “Add Action”. At the selection dialog choose the “Service” action, enter a descriptive name (e.g. “Stop File Sharing”) and hit enter.

Selecting an EventSentry Notification

Then, configure the settings of the service as shown in the screenshot below.

Action to stop the LanmanServer service

The last step of our setup (congratulations if you’ve made it that far) is to assign the service action to the filter we previously created. After all, a service action which isn’t referenced anywhere doesn’t do much good. So head back to the Event Log Packages, find the “CryptoLocker Rules” package and edit the filter in the package. In the action list on top, click the “Add” button and add the action you just created.

Testing
If at all possible I’d recommend testing the EventSentry setup at a time when your users are not interrupted. Adding a few template files to one of the monitored folders and changing them in short succession (a script may be necessary depending on how short your threshold interval is) should trigger the file services shutdown procedure. Once verified, you can just start the “Server” service again.

Conclusion
Just like in the real world, network viruses come in all shapes and sizes – only limited by technology and the imagination of the cyber-evildoers.

I hope that this article gave you some insight into CryptoLocker and a good way to guard against it. As always, make sure that your company has the following in place:

  • Email Attachment scanning
  • Working, tested backups
  • User education
  • AntiSpyware software

With those in place, one should be able to keep future infections to a minimum.

Stay safe & decrypted.

Mobile Alerts: Pushing EventSentry alerts directly to your mobile devices with Prowl and NMA

When it comes to mobile alerts, email seems to still be the prevalent method of choice for many IT pros. There are many good reasons why network alerts delivered via email are convenient:

  • easy to configure
  • uses existing infrastructure
  • every smartphone and tablet supports email
  • supports attachments (e.g. performance charts from EventSentry’s performance alerts)
  • integrates into your existing environment – everybody already uses email!

What’s not to like? Well, of course it turns out that some of these advantages can also be a disadvantage:

  • emails are not real time
  • problems on the email server often don’t surface immediately
  • important alerts can be overlooked in the inbox jungle
  • you cannot be alerted about email problems via email (duh!)

Viable Email Alternatives
Thankfully, there are a number of alternatives that can be used as an email substitute or addition for mobile alerts. In this article I’ll focus on two affordable services: Prowl (for the iOS platform) and Notify My Android (you may have guessed it – for the Android platform) – subsequently referred to as “NMA”. Both of these services consist of apps for their respective platform and a web-based back end which will push the notifications to your device(s) in near real time.

Mobile Alert on iPhone 5 with Prowl

EventSentry event sent to Prowl on an iPhone

Both services offer an HTTP API which we can connect to with EventSentry’s HTTP action. If you have never used the HTTP action in EventSentry, then here is some background: the HTTP action allows you to POST any event (whether it be an event from the security event log or a heartbeat alert for example) to either Prowl’s or NMA’s web service. These notifications are then pushed to one or more mobile devices.

Neither service currently requires a monthly subscription, but both require a purchase (Prowl costs USD 2.99 whereas NMA costs USD 4.99) if you want to send unlimited notifications to your mobile device(s). NMA is a little more welcoming to strangers – it supports up to 5 notifications per day at no charge.

Prowl: Getting Started
The
iOS app costs USD 2.99, and supports up to 1000 API calls (=notifications) per hour. To get started:

  1. Purchase the Prowl: Growl Client from the Apple App Store and install it
  2. Register for free at prowlapp.com
  3. Login & create an API key

Notify My Android (NMA): Getting Started
The Notify My Android app is free in the Google Play store and supports up to 5 API calls (=notifications) per day  for free. Upgrading to a premium account will allow up to 800 API calls per hour. To get started:

  1. Download the Notify My Android app from the Google Play store
  2. Register for free at www.notifymyandroid.com
  3. Login & create an API key
  4. Optional: Upgrade to a Premium account to allow for unlimited notifications

Once you have the mobile app installed and the API key in hand, you can start setting up a HTTP action in EventSentry. Notifications essentially consist of three fields: The application name, a subject as well as a message field, all of which can be customized. As such, it’s up to you configure which part of an event log alert you will put in the subject, and which part you will put into the actual message. In our example, we generate a dynamic notification subject with the host name, event id, event source and event category. The notification body will simply consist of the event message text, though this can be customized as well.

Setting up a HTTP action
Right-click the “Actions” container (or, in v3.0, use the “Add” button in the Ribbon) and create a new HTTP action. The HTTP action requires a URL at minimum, optional credentials and the actual data fields to submit in the HTTP POST. Conveniently, both Prowl & NMA use the same field names. I suspect that they are adhering to some sort of standard, though I couldn’t find any references.

The first parameter to configure is the URL, which depends on the service you use:

Prowl: https://api.prowlapp.com/publicapi/add
NMA: https://www.notifymyandroid.com/publicapi/notify

Configuring authentication credentials is not necessary since you are essentially authenticating with the API key you generated. The last step is configuring the form fields. The bold field on the left is the name of the form element and the text to the right the value. A description follows in italic on the next line:

apikey: abdef123123abababafefefe
The API key you received

application: EventSentry
This will displayed as part of the notification. I use “EventSentry” here, but this can really be anything, so it could be the host name as well for example ($EVENTCOMPUTER)
Max Length: 256

event: $EVENTCOMPUTER-$EVENTID-$EVENTSOURCE-$EVENTCATEGORY
This is the subject of the notification. You can use any variables, including insertion strings $STR1, $STR2 etc.
Max Length: 1024 [Prowl], 1000 [NMA]

description: $EVENTMESSAGE
This is the main message body of the notification, the $EVENTMESSAGE seems like a pretty good candidate for this field
Max Length: 10000

priority: 0 (possible values are -2, -1, 0, 1 and 2)
This field is optional and doesn’t do anything with NMA. With Prowl however, a priority can be set to “2″ (indicating an “emergency”) which may then override quiet hours on the mobile app (if quiet hours are configured in the Prowl mobile app).

Take a look at the respective API documentation for Prowl and NMA as well; each show additional fields which can be configured, as well as additional information that you may or may not find useful.

The screenshot below shows a fully configured HTTP action for Prowl:

EventSentry HTTP Action for Prowl

EventSentry HTTP Action for Prowl

The HTTP action for NMA would look identical, with the exception of the URL which is different. You can click the “Test” button, which will submit the configured data to the specified URL and should, when configured correctly, immediately generate a notification on the mobile device. Please note that event variables will not be resolved when testing.

Threshold
To make sure that your mobile device doesn’t get flooded with alerts (some applications have the tendency to generate not one but hundreds of events in a short period of time), I highly recommend that you setup a threshold on the action or the event log filter referencing the action (I personally prefer the former). You can also setup a schedule so that notifications are only sent on certain days and/or during certain hours.

The last step would be to configure an event log filter to forward select events to the mobile device, something that is beyond the scope of this article. See the tutorials below for more information:

Reliability
It seems only natural to wonder whether alerts sent through these services can be used for mission critical systems. I’ve been using mostly Prowl as I’m an iPhone user, and have been very happy with it’s fast response times (which are almost instant), the service reliability and the stability of the iOS app. Nevertheless, both prowlapp.com and NMA state that you should not solely rely on their system for critical alerts and instead setup multiple channels for mission critical alerts. This sounds nice in theory, but suspect that most sysadmins will not want to dismiss alerts on more than one device – something that can get old if you get a fair number of alerts. Switching to a commercial system like PagerDuty with guaranteed up-time may be preferable in that case. I will talk more about PagerDuty in an upcoming post soon.

My experience with the NMA Android app wasn’t as good during the limited testing I performed. While it worked great when it worked, the app did crash on me a couple of times.

Conclusion
If you’re looking for a way to push alerts to your mobile device from EventSentry without using email and without spending big bucks, Prowl and NMA are worth looking into. They’re affordable, responsive and easy to configure.

Monitoring Windows Updates

Automatic Windows Updates are a wonderful thing when they are working as expected, and many organizations employ WSUS or patch management software to keep their infrastructure up to date with the latest Microsoft hot fixes and service packs.

While this works for many, not everybody can afford patch management software, and, while free, managing the disk-hungry WSUS can be a daunting task as well. This leaves some sysadmins to use the old-fashioned Windows Updates to install all the regular and out-of-band patches Microsoft releases.

If you don’t feel comfortable installing patches automatically however, configuring Windows Update to “download updates for later manual installation” is often safer and more predictable. But, if you’re not logging on to the server(s), you won’t know whether one or more updates are ready for installation or not. Even if you’re just managing one server, checking in on a regular basis can be a waste of time.

updates_are_ready.pngThis is where EventSentry and its log file monitoring feature comes in. It turns out that Windows, like a diligent ship captain, logs all activity to a log file. And with all, I really do mean ALL. The file I’m talking about is windowsupdate.log, and it tells you just about everything that’s going on with Windows Update. In 3-4 steps that don’t take longer than 5 minutes, you can setup real-time monitoring of the WindowsUpdate.log file, and be notified when updates are about to be downloaded to a monitored computer.

The screenshot below shows what such an email from EventSentry would look like:

email_approved_updates.png

From then on, you can either get email notifications when patches are downloaded, or use the web-based reporting to view a report from all of your monitored hosts. On a high level, the configuration works like this:

  • 1. Setup a log file (%systemroot%\windowsupdate.log in this case)
  • 2. Create & assign a new log file package
  • 3. Define a log file filter (this tells EventSentry what to look for in the file, and where to send it)
  • 4. Setup an email action (this is usually already setup)
  • 5. Optionally setup an event log filter to forward alerts to email (the default filter setup should automatically forward warnings)

The WindowsUpdate.log is useful for troubleshooting as well, and you can consolidate the content of this file from all of your servers in the central EventSentry database. This makes searching for text and/or comparing the log from multiple servers a breeze. Having the log file accessible through the web reports is also useful when a patch caused problems and the server is offline. You can view the most recent activity from the log file through the web-based reporting even when the server is unavailable.

So how do you set this up? Assuming you have EventSentry v2.93 installed (any edition will do, including the free “light” version), you can follow the steps outlined below. Note that all steps will need to be performed in the EventSentry management console.


1. Setup a file definition.
This tells EventSentry which file you want to monitor, and sets up a logical representation of that file in the EventSentry configuration. In the “Tools” menu, click “Log Files and File Types” and then click the “Add” button.

menu_tools.png

add_file_definition.png

tree_logfile_package.png

2. Create a package and add a filter. Right-click the “Log File Packages” container, select  “Add Package” and choose a descriptive name. Since new packages are unassigned by default, right-click the newly created package, select “Assign” and assign the package to host(s) on which you want to monitor the Windowsupdate log file.

3. Setup a log file filter. This tells EventSentry which content of the monitored file you are interested in. In every log file filter you can configure a database as well as an event log filter.

Right-click the previously created package and select “Add File”. From the list, select the log file definition created in step 1, “WindowsUpdateLog”. Select the new log file.

The database tab determines which content goes to the database (in most cases you will write all file contents to the database), while the event log tab determines which log file contents are written to the event log. For this project, we are interested in the following wildcard matches:

*AU*# Approved Updates =*

*DnldMgr*Updates to download =*

The first wildcard match will tell you the total number of updates which have been approved and will be downloaded, whereas the 2nd line will fire for every individual update which will be downloaded. In most cases the first line is sufficient and the 2nd line can be skipped.

file_filter_eventlog.png

That’s it! With this setup, you will immediately get notified when patches are ready to be installed. The only thing I didn’t mention here is how to setup an email action and corresponding event log filter, since both of these are usually already setup by default. If you need help with this, please check out our documentation and/or
tutorials.

Please note that the full and evaluation version of EventSentry can inventory installed software and patches. This enables you to use the web interface for viewing/searching installed patches, and get (email) alerts when a patch has been successfully installed.

As always, happy monitoring!

How to make the Windows Software RAID log to the event log

Windows Server has long provided admins the ability to create a software RAID, enabling redundant disks without a (potentially expensive) hardware RAID controller. If you are already using Windows Server 2008′s software RAID capabilities, and think that Windows will somehow notify you when a disk in an array fails, then you can skip to “Just say something!” below.

Background
Creating a RAID can all be done from Disk Management view in the Computer Management console, without any scripting or command-line tools.

Software RAIDs are not as powerful and fast as their hardware counterparts, but are nevertheless a good way to enable disk redundancy. Software RAIDs make sense in a variety of scenarios:

•    When you are on a budget and don’t want to spend a few hundred $$ on a hardware RAID controller
•    When you need to enable redundancy on a server that wasn’t originally designed with redundancy in mind (as if that would ever happen!)
•    When you need to add redundancy to a server without reinstalling the OS or restoring from backup

Windows Server lets you do all this, and it’s included with the OS – so why not take advantage of it? The last point is often overlooked I think – you can literally just add a hard disk to any non-redundant Windows server and create a mirror – with less than dozen clicks!

Since this article is starting to sound like a software raid promotion, and for the sake of completeness, I am listing SOME of the advantages of a hardware RAID here as well:

•    Faster performance due to dedicated hardware, including cache
•    More RAID levels than most software RAIDs
•    Hot-plug replacement of failed disks

•    Ability to select a hot spare disk
•    Better monitoring capabilities (though this article will alleviate this somewhat)

But despite being far from perfect, software RAIDs do have their time and place.

Just Say Something Please!
Unfortunately, despite all the positive things about software RAID, there is a major pitfall on Windows 2008: The OS will not tell you when the RAID has failed. If the RAID is in a degraded state (usually because a hard disk is dead) then you will not know unless you navigate to the Disk Management view. The event logs are quiet, there are no notifications (e.g. tray), and even WMI is silent as a grave. Nothing. Nada. Nix.

What’s peculiar is that this is a step back from Windows 2003, where RAID problems were actually logged to the System event log with the dmboot and dmio event sources. What gives?

Even though a discussion on why that is (or is not) seems justified, I will focus on the solution instead.

The Solution

Fortunately, there is a way to be notified when a RAID is “broken”, thanks in part to the diskpart.exe tool (which is part of Windows) and EventSentry. With a few small steps we’ll be able to log an event to the event log when a drive in a software RAID fails, and send an alert via email or other notification methods.

Diskpart is pretty much the command-line interface to the Disk Management MMC snap-in, which allows you to everything the MMC snap-in does – and much more! One of the things you can do with the tool is to review the status of all (logical) drives. Since we’re interested as to whether a particular RAID-enabled logical drive is “Healthy”, we’ll be looking at logical drives.

So how can we turn diskpart’s output into an email (or other) alert? Simple: We use EventSentry‘s application scheduler to run diskpart.exe on a regular basis (and since the tool doesn’t stress the system it can be run as often as every minute) and generate an alert. The sequence looks like this:

•    EventSentry runs our VBScript (which in turn runs diskpart) and captures the output
•    When a problem is detected, EventSentry logs an error event 10200 to the application event log, including output from step 1.
•    An event log filter looks for a 10200 error event, possibly looking at the event message as well (for custom routing).

Diskpart
Diskpart’s output is pretty straightforward. If you just run diskpart and execute the “list volume” command, you will see output similar to this:


Volume ###  Ltr  Label        Fs     Type        Size     Status     Info   
----------  ---  -----------  -----  ----------  -------  ---------  --------
Volume 0         System Rese  NTFS   Simple       100 MB  Healthy    System  
Volume 1     C                NTFS   Mirror       141 GB  Healthy    Boot    
Volume 2     D   System Rese  NTFS   Simple       100 MB  Healthy           



disk_management_3_cropped.png

Notice the “Status” column, which indicates that our “BOOT” volume is feeling dandy right now.  However, when a disk fails, the status is updated and reads “Failed Rd” instead:


Volume ###  Ltr  Label        Fs     Type        Size     Status     Info   
----------  ---  -----------  -----  ----------  -------  ---------  --------
Volume 0         System Rese  NTFS   Simple       100 MB  Healthy    System  
Volume 1     C                NTFS   Mirror       141 GB  Failed Rd  Boot    
Volume 2     D   System Rese  NTFS   Simple       100 MB  Healthy           

Technically, scripting diskpart is a bit cumbersome, as the creators of the tool want you to specify any commands to pass to diskpart in a text file, and in turn specify that text file with the /s parameter. This makes sense, since diskpart can automate partitioning, which can certainly result in a dozen or so commands.

For our purposes however it’s overkill, so we can trick diskpart by running a single command:

echo list volume | diskpart

which will yield the same results as above, without the need of an “instruction” file.

The easy way out
The quickest way (though per usual not the most elegant) to get RAID notifications is to create a batch file (e.g. list_raid.cmd) with the content shown earlier

echo list volume | diskpart

and execute the script on a regular basis (e.g. every minute) which will result in the output of the diskpart command being logged to the event log as event 10200.

Then, you can create an include filter in an event log package, which will look for the following string:

*DISKPART*Status*Failed Rd*

If your EventSentry configuration is already setup to email you all new errors then you don’t even have to setup an event log filter – just creating the script and scheduling it will do the trick.

But surely you will want to know how this can be accomplished in a more elegant fashion? Yes? Excellent, here it is.

A Better Solution

One problem with the “easy way out” is that it will not detect all Non-Ok RAID statuses, such as:

•    At Risk
•    Rebuild

disk_management_resync.pngFurthermore, the output can be rather verbose, and will include any logical drive, include CD-ROMs, removable disks and others.

It is for this reason we have created a VBScript, which will parse the output of the diskpart command with a regular expression, and provide the following:

•    A filtered output, showing only drives in a software raid
•    Formatted output, showing only relevant drive parameters
•    Detecting any Non-Healthy RAID

Alas, an example output of the script is as follows:

Status of Mirror C: (Boot) is "Healthy"

Much nicer, isn’t it? If a problem is detected, then output will be more verbose:

**WARNING** Status of Mirror C: (Boot) is "Failed Rd"

   
WARNING: One or more redundant drives are not in a "Healthy" state!

The VBScript will look at the actual “Status” column and report any status that is not “Healthy”, a more accurate way to verify the status of the RAID.

Since the script has a dynamic ERRORLEVEL, it’s not necessary to evaluate the script output – simply evaluating the return code is sufficient.

Implementation
Let’s leave the theory behind us and implement the solution, which requires only three steps:

1.    Create an embedded script (we will include this script with v2.93 by default) through the Tools -> Embedded Scripts option, based on the VBScript below. Select “cscript.exe” as the interpreter. Embedded scripts are elegant because they are automatically included in the EventSentry configuration – no need to manage the scripts outside EventSentry.

monitor_raid_embedded_script.png2.    Create a new System Health package and add the “Application Scheduler” object to it. Alternatively you can also add the Application Scheduler object to an existing system health package. Either way, schedule the script with a recurring schedule.

application_scheduler_monitor_raid.pngNote that commands starting with the @ symbol are embedded scripts. The “Log application return code 0 to event log …” option is not selected here, since the script runs every minute and would generate 1440 entries per day. You may want to enable this option first to ensure that your configuration is working, or if you don’t mind having that many entries in your application log. It’s mainly a matter of preference.

3.    This step is optional if you already have a filter in place which forwards Errors to a notification. Otherwise, create an event log filter which looks for the following properties:

  Log: Application
  Severity: Error
  Source: EventSentry
  ID: 10200
  Text (optional): “WARNING: One or more redundant drives*”


The VBScript


‘ Lists all logical drives on the local computer which are configured for
‘ software RAID. Returns an %ERRORLEVEL% of 1 if any redundant drive is
‘ not in a “Healthy” state. Returns 0 otherwise.

‘ Supports Windows Vista/7, Windows 2008/R2

Option Explicit

Dim WshShell, oExec
Dim RegexParse
Dim hasError : hasError = 0

Set WshShell = WScript.CreateObject(“WScript.Shell”)
Set RegexParse = New RegExp

‘ Execute diskpart
Set oExec = WshShell.Exec(“%comspec% /c echo list volume | diskpart.exe”)

RegexParse.Pattern = “\s\s(Volume\s\d)\s+([A-Z])\s+(.*)\s\s(NTFS|FAT)\s+(Mirror|RAID-5)\s+(\d+)\s+(..)\s\s([A-Za-z]*\s?[A-Za-z]*)(\s\s)*.*”

While Not oExec.StdOut.AtEndOfStream
    Dim regexMatches
    Dim Volume, Drive, Description, Redundancy, RaidStatus
    Dim CurrentLine : CurrentLine = oExec.StdOut.ReadLine
    
    Set regexMatches = RegexParse.Execute(CurrentLine)
    If (regexMatches.Count > 0) Then
        Dim match
        Set match = regexMatches(0)
        
        If match.SubMatches.Count >= 8 Then
            Volume      = match.SubMatches(0)
            Drive       = match.SubMatches(1)
            Description = Trim(match.SubMatches(2))
            Redundancy  = match.SubMatches(4)
            RaidStatus  = Trim(match.SubMatches(7))
        End If

        If RaidStatus <> “Healthy” Then
            hasError = 1
            WScript.StdOut.Write “**WARNING** “
        End If
        
        WScript.StdOut.WriteLine “Status of ” & Redundancy & ” ” & Drive & “: (” & Description & “) is “”” & RaidStatus & “”””
    End If
Wend

If (hasError) Then
    WScript.StdOut.WriteLine “”
    WScript.StdOut.WriteLine “WARNING: One or more redundant drives are not in a “”Healthy”” state!”
End If

WScript.Quit(hasError)



How to dynamically toggle your Wireless adapter with EventSentry

Most of the time I work on a Lenovo laptop running Windows 7, and I’m overall quite happy with the laptop (especially after the mainboard was replaced and it stopped randomly rebooting). However, a minor nuance had been bugging me for a while: If I plugged my computer into a LAN (I have a docking station at work and at home) while a wireless signal was also available (and configured on the laptop), Windows 7 would keep both connections active.

1. The Problem

So I’d have my laptop in the docking station, connected to a 1Gb Ethernet network, and yet the laptop would also be connected to a WiFi network. While not a big deal per se, it does have a few advantages to automatically disable the WiFi connection when already connected to Ethernet:

  • Avoid potential connectivity issues
  • Increase security by not transmitting data via Wifi when not necessary
  • Increase battery life when connected to a LAN
  • Because you can!

Now, Lenovo equips most (if not all) laptops with a software called “Access Connections”, a pretty nifty and free tool! One of the things it can do, is disable a Wireless adapter when the computer is connected to Ethernet. However, it never re-enables it when you disconnect from the wired network (at least I haven’t found a way), and besides not everybody has Lenovo laptop.

So how could I disable the WiFi connection automatically when I connected the laptop to an Ethernet, yet automatically re-enable it when there is no Ethernet connection?

2. The Research

After some intense brainstorming, I remembered two things:

  1. Most Ethernet NIC drivers log event to the System event log when a network port is connected/disconnected.
  2. A while back, I used the netsh command to configure DNS servers from the command line. Maybe one could toggle the state of network adapters with this tool as well?

3. Evidence Gathering

The first one was easy, a quick look at the system event log revealed the following event:

e1kexpress_event.pngA similar event is logged when the “network link” has connected. The event shown here is specific to the driver of my laptop’s network card (an Intel(R) 82577LM adapter), but most newer drivers will log events when a cable is disconnected or the link is otherwise lost. If you are already running EventSentry with its hardware inventory feature enabled, then you can obtain the name of the network adapter from any monitored host on the network through the hardware inventory page, an example is shown below.

all_nics.pngComing up with a way to enable and disable a particular network connection with netsh.exe was a bit more challenging, but I eventually cracked the cryptic command line parameters of netsh.exe.

Enable a connection
netsh interface set interface “Wireless Network Connection” ENABLED

Disable a connection

netsh interface set interface “Wireless Network Connection” DISABLED

And yes, you do need to specify the word “interface” twice. If you do find yourself wanting to automate network adapter settings with scripts and/or the command line frequently, then you should check out this link.

4. The Solution

So now that we have all the ingredients, let’s take a look at the recipe. In order to accomplish the automatic interface toggling, we need to create:

  • an embedded script called wifi_enable.cmd, using the command line from above
  • an embedded script called wifi_disable.cmd, again using the command line from above
  • a process action “Wifi Enable”, referencing the above wifi_enable.cmd embedded script
  • a process action “Wifi Disable”, referencing the above wifi_disable.cmd embedded script
  • an event log filter for event source “e1kexpress” and event id 27, triggering the “Wifi Enable” action
  • an event log filter for event source “e1kexpress” and event id 32, triggering the “Wifi Disable” action

A couple of clarifications: First, you do not need to use embedded scripts, you can create the scripts in the file system too and then point the process action to those files. I prefer embedded scripts since I don’t have to worry about maintaining the script, as it gets distributed to remote hosts automatically when needed. Second, the event source and event id will depend on the network card you have installed on your network, the above example will only work with Lenovo T410 laptops.

So what happens is pretty straightforward: When I connect my laptop to a LAN, the Intel NIC driver writes event id 32 with the event source e1kexpress to the system event log. EventSentry intercepts the event and triggers the Wifi Disable action, which in turns runs the netsh.exe process, disabling the WiFi connection.

5. Setting it up in the management console

Embedded Scripts

You can manage embedded scripts via Tools -> Embedded Scripts. Click “New”, specify a descriptive name (e.g. wifi_enable.cmd) and paste the command line netsh interface set interface “Wireless Network Connection” ENABLED into the script content window. Then, do the same for the wifi_disable.cmd script, but this time use the netsh interface set interface “Wireless Network Connection” DISABLED command line. You can leave the interpreter empty as long as you give the filename the .cmd extension.

embedded_script.pngActions

Create two process actions, one pointing to wifi_enable.cmd, and one pointing to wifi_disable.cmd. You can access these embedded scripts by clicking the pull-down – you should see the embedded script(s) you created in step one – each prefixed with the @ symbol. The resulting dialog should look like this:

process_wifi_enable.pngI recommend enabling both “Event Log Options”, as this will help with troubleshooting. Now we just need the event log filters, and we are all set.

Like I mentioned earlier, you can also reference any external process or .cmd file with the process action, if you’d rather not use embedded scripts.

Event Log Filters
Since we’ll need two filter, we’ll create a new event log package called “Toggle Wifi” by right-clicking the “Event Log Packages” container and selecting “Add Package”. Inside the package we can then add the two filters: One to trigger the “Wifi Enable” action when the NIC drivers logs its event indicating that the network cable was unplugged, and one that will trigger the “Wifi Disable” action when the NIC drivers logs that the network cable was plugged in. The filter will look similar to this, but note that the event source as well as event id will depend on the network card and driver.

filter_wifi_enable.pngThat’s pretty much it. If you enabled the event log options in the process action earlier, then you can see the output from the process action in the event log, as shown below:

event_action.pngHere are some links to the official EventSentry documentation regarding the features used: