DGA (“Domain Generation Algorithm“) is a technique implemented in some malware families to defeat defenders and to make the generation of IOC’s (and their usage – example to implement black lists) more difficult. When a piece of malware has to contact a C2 server, it uses domain names or IP
If it’s common to say that “Everything is a Freaking DNS problem“, other protocols can also be the source of problems… NTP (“Network Time Protocol”) is also a good candidate! A best practice is to synchronize all your devices via NTP but also to set up the same timezone! We
I published the following diary on isc.sans.edu: “Malicious Excel Delivering Fileless Payload“: Macros in Office documents are so common today that my honeypots and hunting scripts catch a lot of them daily. I try to keep an eye on them because sometimes you can spot an interesting one (read: “using a less common
I published the following diary on isc.sans.edu: “Anti-Debugging JavaScript Techniques“: For developers who write malicious programs, it’s important to make their code not easy to be read and executed in a sandbox. Like most languages, there are many ways to make the life of malware analysts mode difficult (or more
I published the following diary on isc.sans.edu: “Anti-Debugging Technique based on Memory Protection“: Many modern malware samples implement defensive techniques. First of all, we have to distinguish sandbox-evasion and anti-debugging techniques. Today, sandboxes are an easy and quick way to categorize samples based on their behavior. Malware developers have plenty
I published the following diary on isc.sans.edu: “AgentTesla Delivered via a Malicious PowerPoint Add-In“: Attackers are always trying to find new ways to deliver malicious code to their victims. Microsoft Word and Excel are documents that can be easily weaponized by adding malicious VBA macros. Today, they are one of
I published the following diary on isc.sans.edu: “Malware Triage with FLOSS: API Calls Based Behavior“: Malware triage is a key component of your hunting process. When you collect suspicious files from multiple sources, you need a tool to automatically process them to extract useful information. To achieve this task, I’m using
I published the following diary on isc.sans.edu: “Keeping an Eye on Malicious Files Life Time“: We know that today’s malware campaigns are based on fresh files. Each piece of malware has a unique hash and it makes the detection based on lists of hashes not very useful these days. But
I published the following diary on isc.sans.edu: “Powershell Payload Stored in a PSCredential Object“: An interesting obfuscation technique to store a malicious payload in a PowerShell script: In a PSCredential object! The PSCredential class can be used to manage credentials in a centralized way. Just have a look at this example. First, let’s encrypt
I published the following diary on isc.sans.edu: “Malicious Excel With a Strong Obfuscation and Sandbox Evasion“: For a few weeks, we see a bunch of Excel documents spread in the wild with Macro V4. But VBA macros remain a classic way to drop the next stage of the attack on the
