160. Detecting Recent Kimsuky Campaign

Hello everyone!

The Genians Security Center (GSC) reported on a recent Kimsuky (we track this activity cluster as Monolithic Werewolf) campaign, which took place in between March and April 2025. Interesting enough that the adversary leveraged multiple communication channels to distribute malicious files, including email, Facebook and Telegram.

The installation process is quite noisy as always, so we have lots of detection opportunities. For example, the threat actors abused PowerShell and Certutil for decoding:

"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -windowstyle hidden certutil -decode C:\Windows\..\ProgramData\ffBqrQ6.rppn C:\Windows\..\ProgramData\sRPCU5y.evJl

A good candidate for detection, right?

event_type: "processcreatewin"

AND

proc_file_name: "powershell.exe"

AND

cmdline: ("certutil" AND "decode")

One more thing - abusing reg.exe to achieve persistence:

reg add HKCU\Software\Microsoft\Windows\CurrentVersion\Run /d "regsvr32.exe /s C:\Users\Alice\.edge\softUpdate.db" /t REG_SZ /v ServiceUpdate /f

We can use this behavior to build detection as well:

event_type: "processcreatewin"

AND

proc_file_name: "reg.exe"

AND

cmdline: ("add" AND "regsvr32")

Also, make sure to have a hunting query for regsvr32.exe as it's commonly abused by various adversaries!

See you tomorrow!

Comments

Post a Comment

Popular posts from this blog

033. Free Google Threat Intelligence Course

Image
Hello everyone! Everybody loves free courses, right? Have you missed a free course on Google Threat Intelligence ? If the answer is "Yes", it's your chance to check it!  I like this course as it not only overviews the capabilities of Google Threat Intelligence as a product, but also covers various threat intelligence use cases, for example, how to empower incident response and forensic investigations or how to use it for adversary hunting and tracking. I've already got my completion badge: What about you? See you tomorrow!
Read more

082. Huniting for Malicious Browser Extensions

Image
Hello everyone! Malicious browser extensions are stopping to be an exotic threat. For example,  Rilide . It was first reported in April 2023, but became a common threat, and this report is another proof of it. Can we hunt for such extensions? Of course, yes! For example, usually threats like Rilide modify browser-reated LNK files to run it with " --load-extension " argument, like this: chrome.exe --load-extension="C:\Users\user\AppData\Local\Temp\MalExt" It means we can hunt for execution of common Chromium-based browsers with this argument: event_type: "processcreatewin" AND proc_file_name: ("chrome.exe" OR "brave.exe" OR "opera.exe" OR "msedge.exe")  AND cmdline: "load-extension" I'm sure you'll get false positives, but this is what we expect from threat hunting, right? Proper filtering will help you, I'm sure! See you tomorrow!
Read more

001. The Zeltser Challenge

Image
Hello everyone! Happy New Year! New year - new challenges! So, a few weeks ago David Cowen reminded me about the Zeltser challenge. What's the point? You must blog every day for a year to push yourself to research and write. Sound cool, right? Dave suggested to start the challenge with him on 1/1/25, and that's why you are reading this post! So, what am I going to share here? I'm a big fan of intelligence-led approach to cyber defense, so every day we'll look at this or that technique (or sub-technique) leveraged by real adversaries, so we can learn more about our enemies.  We'll look both at public reporting and private findings by BI.ZONE Threat Intelligence team. Stay tuned, and see you tomorrow!
Read more