mandiant / mandiant/capa-rules

null-preserving XOR not identified

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enhancement
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Description

capa doesn't detect null-preserving XOR because the XOR is not in a tight loop. Can we detect it?
Screenshot 2023-11-06 at 15 20 47

Tested with capa 6.1.0 using sample 4ce210df92602f9cf4990357eb63f1f05cb5e89d03426a98a77ef98d6ff967bc

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Research direction

Reproduce the report with capa 6.1.0 and sample 4ce210df92602f9cf4990357eb63f1f05cb5e89d03426a98a77ef98d6ff967bc, then inspect the existing rules for null-preserving XOR behavior. Done means capa detects the null-preserving XOR when it is not in a tight loop, with a regression check covering the sample.

Written by the indexing model from the issue text.

Assessment

Domain
reverse-engineering
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
42/100

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