051. Bloody Wolf's Techniques From Detection Perspective

Hello everyone! Let's talk about recently uncovered techniques leveraged by Bloody Wolf activity cluster.

The threat actors rely on phishing emails and distribute legitimate PDF file with malicious links. These links are used to deliver malicious JAR files. They used to distribute STRRAT, but in recent campaigns changed it to legitimate remote access software commonly abused by various adversaries - NetSupport.


Details are available in the report, but let's look at some of detection opportunities. The victim clicks the phishing link and downloads a JAR file. Usually, it's located under Downloads folder. What about execution? Java is used to execute it, usually with -jar parameter. What's more, user must execute it, so the parent process for Java should be explorer.exe. Here's what we got:

event_type: "processcreate" 

AND 

proc_p_file_path: "explorer.exe" 

AND 

cmdline:("java" AND "jar" AND "Downloads")

To get the list of download links for NetSupport components, executed JAR file requests pastebin[.]com - and this is another detection opportunity:

event_type: "dnsreq" 

AND

dns_rname: "pastebin.com"

AND

proc_cmdline:("java" AND "jar" AND "Downloads")

Let's look at NetSupport itself as well. As always, it can be renamed, so let's focus on the original file name and uncommon locations:

event_type: "processcreate"

AND

proc_file_originalfilename: "client32.exe"

AND NOT

proc_file_path: "program files"

I'm you spotted even more detection opportunities in the report! Share them in the comments!

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