Windows supports a code-signing feature called Authenticode, which allows a software publisher to digitally sign executable files (e.g. .exe, .msi, …) so that users can verify their autenticity. The digital signature of a file can be viewed in the file properties in Windows explorer on the “Digital Signature” tab.
In part one I provided a high level overview of PowerShell and the potential risk it poses to networks. Of course we can only mitigate some PowerShell attacks if we have a trace, so going forward I am assuming that you followed part 1 of this series and enabled: Module Logging, Script Block Logging, Security Process Tracking (4688/4689)
Imagine someone getting the seemingly innocent ability to run a couple of commands on a machine on your network WITHOUT installing any new software, but those commands resulting in a reverse shell running on that same machine – giving the intruder a convenient outpost in your network. Now stretch your imagination even further and pretend that all of this happens without leaving any unusual traces in logs – leaving you completely in the dark.
In Mr. Robot‘s episode 9 of season 2 (13:53), Angela Moss needs to obtain the Windows domain password of her superior, Joseph Green, in order to download sensitive documents that would potentially incriminate EvilCorp. Since her attack requires physical access to his computer, she starts with a good old-fashioned social engineering attack to get the only currently present employee in the office to leave.
With the proper auditing enabled (Logon/Logoff – Logon (Failure)) and EventSentry installed however, we can permanently block remote users / hosts who attempt to log on too many times with a wrong password. Setting this up is surprisingly simple.
If you’re running Windows 2008 (R2) or 2012 then setting up DNS auditing requires a few steps. Thankfully it’s a one-time process and shouldn’t take more than a few minutes. On the EventSentry side a pre-built package with all the necessary rules is available for download and included with the latest installer.
