blue tangle

    Time for part 2 of a few blogposts on threat actors disabling Windows updates. We covered why in the last post along with how, this time around we will be mostly focusing on detections.   We aren't just detecting disabled Windows updates though, we're detecting the steps required to actually delete and remove installed updates. First we look at usage of the Windows native binary takeown , which enables an administrator to recover access to files that was previously denied.   In this case we are looking at takeown grabbing access of folders relating to Windows updates Our Splunk search looks like this:   index=winlogs EventCode=4688  Process_Command_Line IN ("*\Windows 10 install\*", "*\Windows10Upgrade\*")  New_Process_Name="*\\takeown. exe" | stats  min(_time) AS earliest max(_time) AS latest count(Process_Command_Line) AS Count values(Process_Command_Line) AS Process_Command_Line BY Creator_Process_Name Account_Name ComputerName  | c

  There is never necessarily a good time for Windows updates, but if you are running Windows and care about security, you're going to have to do it eventually, right? Some Threat Actors would prefer that those updates remain uninstalled though, this blog and the research that went into it is inspired by this Scadafence paper entitled " Anatomy of a Targeted Ransomware Attack " which includes this list, pay particular attention to 2. "Disabling Windows updates", this got me thinking. I had a look through ATT&CK to try to map this TTP but to no avail, asking in the ATT&CK Slack I think "Impair Defenses: Disable or Modify Tools" (T1562.001) or "Service Stop" (T1489) seem most appropriate, but I'll leave it up to you as it could fit under a few techniques. I couldn't find any detections for this, so I decided to make my own and share them. Why would a threat actor want to stop Windows updates or even roll them back? I think TAs, e