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Author here. We were analyzing a compromised contributor account targeting better-auth when we noticed something interesting about the attack vector. Most cover
by brene 5mo ago
Author here. We were analyzing a compromised contributor account targeting better-auth when we noticed something interesting about the attack vector. Most coverage of supply chain attacks focuses on the "what happened" but I wanted to document the "how it actually works" with the deobfuscated code.
Wwo things stood out:
1. hiding the payload in next.config.mjs is clever because GitHub's UI truncates long lines so the malicious string is literally invisible when scrolling through the file. second, storing the c2 payload on binance smart chain means theres no server to take down. The axios attack was mitigated by removing the GitHub-hosted payload. This one can't be.
2. found 30+ repos with the same signature string. Pretty sure there's way more we didn't catch with basic string matching.
happy to answer questions about the deobfuscation process or the c2 protocol analysis.
- WalterGR 5mo ago> GitHub's UI truncates long lines so the malicious string is literally invisible when scrolling through the file. It looks like the screen recording was made on a Mac. Does your browser (Chrome?) respect the OS-wide ‘Always show scroll bars’ setting? After all, it’s not that GitHub is “truncating” the lines, it’s that scroll bars aren’t visible - so it’s not immediately obvious that there’s code outside of the viewport.
- sysguest 5mo ago> it’s that scroll bars aren’t visible well truncating or not, that seems to be a major security UI issue...?
- rho138 5mo agoYour website fingerprints devices so hard it throws a warning after rendering content.
- brene 5mo agoare you using Safari's Lockdown Mode?
- PeterWhittaker 5mo agoWhat if they are? Why should people attempting to browse securely be punished?
- brene 5mo agoJust debugging the issue :-)