Critical-review §2 B7 finding: pure Levenshtein <=2 misses the most common
modern typosquat pattern — popular-name + token-injection suffix. Examples:
lodash → lodash-utils (edit distance 6, not flagged pre-B7)
react → react-helper (edit distance 7, not flagged pre-B7)
express → express-wrapper (edit distance 8, not flagged pre-B7)
Three coordinated edits:
scanners/lib/string-utils.mjs
- Adds tokenize(name): string[] splits on -/_, lowercases
- Adds tokenOverlap(a, b): number intersection.size / min(|a|,|b|)
- Adds TYPOSQUAT_SUSPICIOUS_TOKENS frozen list of common typosquat
suffixes. Excludes language-extension tokens (js, jsx, ts, tsx) — the
v7.0.0 allowlist contains `tsx` as a legit package and including the
same token in the suspicious set creates a contradiction. Caught by
the new allowlist-intersection-guard test. Also excludes 'pro'
(legitimate edition marker).
scanners/dep-auditor.mjs + scanners/supply-chain-recheck.mjs
- New checkTyposquatTokenOverlap() helper — fires AFTER Levenshtein 1/2
branches, only when:
1. popular package's tokens ⊆ declared name's tokens (strict superset)
2. declared name has at least one suspicious suffix
3. popular package is in topCutoff window
All three conditions required — conservative by design. Allowlist
precedence preserved (existing 22 npm + 13 PyPI entries always pass).
MEDIUM severity, NOT block. New finding title prefix:
"Possible typosquatting via token-overlap".
Tests: +21 cases across two new files
- tests/lib/string-utils-tokens.test.mjs (15) — tokenize, tokenOverlap,
TYPOSQUAT_SUSPICIOUS_TOKENS frozen contract, allowlist-intersection
guard (caught the tsx conflict on first run)
- tests/scanners/dep-token-overlap.test.mjs (7) — integration via
in-memory tmpdir fixtures: lodash-utils flagged, react-helper flagged,
express-wrapper flagged, lodash exact NOT flagged, allowlist tools
(knip/tsx/nx/rimraf) NOT flagged, react-router-dom (no suspicious
suffix) NOT flagged, react itself (equal token set, not superset)
NOT flagged.
Existing dep.test.mjs and supply-chain-recheck.test.mjs unchanged —
all green (149 → 149 regression guard).
Suite: 1570 → 1591 (+21). All green.
