I published the following diary on isc.sans.edu: “Live Patching Windows API Calls Using PowerShell“: It’s amazing how attackers can be imaginative when it comes to protecting themselves and preventing security controls to do their job. Here is an example of a malicious PowerShell script that patches live a DLL function
I published the following diary on isc.sans.edu: “Malicious Python Code and LittleSnitch Detection“: We all run plenty of security tools on our endpoints. Their goal is to protect us by preventing infection (or trying to prevent it). But all those security tools are present on our devices like normal applications
I published the following diary on isc.sans.edu: “PowerShell Dropper Delivering Formbook“: Here is an interesting PowerShell dropper that is nicely obfuscated and has anti-VM detection. I spotted this file yesterday, called ‘ad.jpg’ (SHA256:b243e807ed22359a3940ab16539ba59910714f051034a8a155cc2aff28a85088). Of course, it’s not a picture but a huge text file with Base64-encoded data. The VT score is therefore
I published the following diary on isc.sans.edu: “When Security Controls Lead to Security Issues“: The job of security professionals is to protect customers’ assets and, even more, today, customers’ data. The security landscape is full of solutions that help to improve security by detecting (and blocking) threats knocking on the
I published the following diary on isc.sans.edu: “Old Worm But New Obfuscation Technique“: Yesterday I found an interesting JavaSvript script delivered through a regular phishing campaign (SHA256:70c0b9d1c88f082bad6ae01fef653da6266d0693b24e08dcb04156a629dd6f81) and has a VT score of 17/61. The script obfuscation is simple but effective: the malicious code is decoded and passed to an eval()
I published the following diary on isc.sans.edu: “How Attackers Brush Up Their Malicious Scripts“: On Friday, I received a bunch of alerts from one of my YARA hunting rules. Several samples were submitted from the same account (through the VT API), from the same country (US), and in a very
I published the following diary on isc.sans.edu: “Did You Spot “Invoke-Expression”?“: When a PowerShell script is obfuscated, the deobfuscation process is, most of the time, performed through the Invoke-Expression cmdlet. Invoke-Expression evaluates the string passed as an argument and returns the results of the commands inside the string… [Read more]
I published the following diary on isc.sans.edu: “Quick Status of the CAA DNS Record Adoption“: In 2017, we already published a guest diary about “CAA” or “Certification Authority Authorization”. I was curious about the status of this technique and the adoption level in 2020. Has it been adopted massively since
If you follow my blog for a while, you probably noticed that I’m not really active with new content. Most articles are published through the SANS ISC Website but it does not mean I don’t have content to publish. It’s just a question of time like many of us! Recently,
I published the following diary on isc.sans.edu: “Mirai-alike Python Scanner“: Last week, I found an interesting Python script that behaves like a Mirai bot. It scans for vulnerable devices exposing their telnet (TCP/23) interface in the wild, then tries to connect using a dictionary of credentials. The script has been uploaded to
