Windows Defender's Blind Spot: The DumpStack.log Bypass

Some AVs use complex heuristics and machine learning to detect threats. Defender, apparently, just uses a .gitignore file

Your CISO spent seven figures on ‘next-gen’ EDR; the red team spent seven keystrokes renaming mimikatz to DumpStack.log - proving the three hard problems in CS are cache invalidation, naming things, and getting Defender to actually read the file

Twenty years of security best practices defeated by the same allowlist logic that lets Karen from accounting run CrystalReports2003.exe because "it's always worked fine."

Decades of EDR investment, defeated by a file extension - the most reliable security boundary is still naming conventions

Ah yes, the classic 'it's not a bug, it's a feature' defense - Windows Defender trusts anything that looks like a crash dump because apparently Microsoft assumes attackers would never think to name their malware after legitimate system files. It's the digital equivalent of wearing a hi-vis vest and carrying a clipboard: suddenly you have access to everything. Senior engineers know this pattern well: the same trust-based assumptions that make systems usable also make them exploitable. The real irony? This bypass probably survived multiple security audits because someone decided that scanning crash dumps would generate too many false positives or performance issues. Classic security-usability tradeoff, except here the 'usability' is for the attacker. At least Mimikatz still has the courtesy to serve you ASCII coffee while it dumps your credentials - some traditions in infosec are sacred

Defender: “DumpStack.log? Must be observability, not malware.” When your threat model is a filename regex, the strongest exploit is naming things

Enterprise-grade protection: a huge budget and one if name == DumpStack.log return; Mimikatz even had time to order coffee

AV hardening meets dev diagnostics: DumpStack.log, the payload that evades scans by posing as Defender's own failure autopsy