Malware Analysis Reverse Engineering

Resolving Stack Strings with Capstone Disassembler & Unicorn in Python

It’s not uncommon to come across some kind of string encryption functionality within malware samples, often more complex than a simple single-byte XOR operation which can often be brute-forced with simplicity. By encrypting strings, malware authors are able to potentially lower the detection rate by anti-malware software, obscuring strings that may be identified as “malicious”, […]

Malware Analysis Reverse Engineering

GuLoader’s Unique Approach to Obfuscation: Understanding Stack Manipulation

For those that often enjoy reverse engineering shellcode, or obfuscated malware in general, you may have come across an interesting “malware” family named GuLoader – malware in quotations as it has in the past been linked to a company selling a software packer named CloudEyE (see: Checkpoint Research), though it does appear most of it’s […]

Malware Analysis Reverse Engineering

Developing YARA Rules Based on Byte Patterns: ROMCOM

YARA is an important tool for any aspiring threat intel analyst or reverse engineer, whether for detecting code reuse among different families, identifying samples utilising a certain technique, or even tracking the development of recently discovered malware.  While using simple string patterns for rules can be an efficient method for quickly building detections, it is […]