Kaspersky analysis of the backdoor in XZ
Kaspersky analysis of the backdoor recently found in XZ, which is used in many popular Linux distributions and in OpenSSH server process.
GitHub - amlweems/xzbot: notes, honeypot, and exploit demo for the xz backdoor (CVE-2024-3094)
notes, honeypot, and exploit demo for the xz backdoor (CVE-2024-3094) - amlweems/xzbot
xz/liblzma: Bash-stage Obfuscation Explained - gynvael.coldwind//vx.log
esterday Andres Freund emailed oss-security@ informing the community of the discovery of a backdoor in xz/liblzma, which affected OpenSSH server (huge respect for noticing and investigating this). Andres' email is an amazing summary of the whole drama, so I'll skip that. While admittedly most juicy and interesting part is the obfuscated binary with the backdoor, the part that caught my attention – and what this blogpost is about – is the initial part in bash and the simple-but-clever obfuscation methods used there. Note that this isn't a full description of what the bash stages do, but rather a write down of how each stage is obfuscated and extracted.