Scanning this repository with the SIG scanner produced 7 findings, 4 of them
on our own detection data: scanners/commons/CHANGELOG.md and
scanners/commons/signatures/malware-signatures.json. The ruleset that describes
xmrig and webshells is, byte for byte, a document containing those strings, so
the engine matched it as malware. EXCLUDED_PATH_RE already carried
knowledge/, tests/, docs/ and node_modules/ for exactly this reason; the
vendored commons arrived in v8 Phase 5 (bbada84) without being added.
One alternation branch closes it. Tests first: two cases added to
describe('signature-scanner: path exclusions'), both verified red against the
real scan() entry point before the regex changed.
Stated plainly, because it is a real cost and not a technicality: the branch is
`scanners\/commons` behind the existing `(^|\/)` prefix, so it matches that
two-segment path ANYWHERE in a target's relative path, not only at its root. A
webshell planted at vendor/scanners/commons/shell.php in a hostile repository is
therefore invisible to SIG. The second new test asserts that blind spot
deliberately, so it can never be discovered by accident. It is accepted because
anchoring at ^scanners/commons/ would miss the same payload one directory
deeper while re-opening the self-flag whenever the plugin is scanned from a
parent directory. TRG, AST, entropy and supply-chain still read these files;
only SIG identity-matching is blinded.
scanners/lib/supply-chain-data.mjs is NOT excluded. Its finding is a true
positive against real blocklist data.
Measured before: 7 findings. After: 3 (2 on STATE.md, 1 on
supply-chain-data.mjs). signature-scanner.test.mjs 23/23; custom-rules + e2e
54/54; golden-baseline 8/8 with suite-counts.json untouched.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SBJVYzwch63Rpk1hii1cNM
Kjell Tore Guttormsen
eceb71bbb3