Critical-review §4 E16 finding: pre-v7.2.0 homoglyph normalization fired
ONLY for the MEDIUM-advisory "obfuscation present" signal. Pattern
matchers in scanForInjection compared against raw + decoded variants
only — they did NOT compare against a fold-normalized variant. As a
result, "ignоre previous instructions" (Cyrillic о, U+043E) bypassed
the CRITICAL "ignore previous" pattern.
Two coordinated edits:
scanners/lib/string-utils.mjs
- Adds HOMOGLYPH_MAP (frozen) — surgical Cyrillic/Greek → Latin map.
~25 entries focused on injection-vocabulary letters
(a, e, o, c, p, x, y, i, j, s, l, A, E, O, C, P, X, Y, T).
- Adds foldHomoglyphs(s) — pipeline: NFKC → apply HOMOGLYPH_MAP.
NFKC handles Mathematical Alphanumeric (U+1D400 block), fullwidth
Latin (U+FF21 block), ligatures, width variants.
Excluded by design from HOMOGLYPH_MAP:
- Latin Extended (æ, ø, å, é, è, ñ, ü, ö, ä, ç, ß, þ, ð) — legitimate
Norwegian/German/French/Spanish letters. Map them and we false-positive
on every non-English source file.
- Greek letters not visually overlapping (β, γ, δ, ...)
- Cyrillic letters not visually overlapping (б, г, д, ж, ...)
scanners/lib/injection-patterns.mjs
- scanForInjection now builds a 4-variant set: raw, normalized,
folded(raw), folded(normalized). Set deduplication skips redundant
identical variants. Existing dedup-by-label (seenLabels Set) prevents
double-counts when the same pattern matches in multiple variants.
- foldHomoglyphs added to the imports.
Tests: +27 cases in tests/lib/string-utils-homoglyph.test.mjs:
- 6 Cyrillic → Latin (lowercase, uppercase, multiple substitutions,
Palochka U+04CF)
- 3 Greek → Latin
- 2 NFKC normalization (Math Bold, Fullwidth)
- 8 preserves-non-confusable (Norwegian æøå, German umlauts, French
accents, Spanish ñ, emoji, CJK, Arabic/Hebrew)
- 3 edge cases (empty, null/undefined, idempotency)
- 5 scanForInjection integration (Cyrillic ignore, Cyrillic Assistant,
Norwegian non-trigger, benign "ignore" comment, mixed Cyrillic+Greek)
Test-development found: U+1D5DC is "I" not "A" (test pin caught my
codepoint mistake — fixed during dev).
Suite: 1617 → 1644 (+27). All green.
Critical-review §4 E1 finding: pre-v7.2.0 the Unicode-stego detector
(`containsUnicodeTags`) covered only U+E0001-E007F (Tag block). Private
Use Areas — also invisible in most terminals and surviving normalization
— were not detected. Attackers could encode payloads in PUA codepoints
that pass through `scanForInjection` undetected.
Coverage extended to:
- U+E0001-E007F Unicode Tag block (existing — DeepMind kat. 1)
- U+F0000-FFFFD Supplementary PUA-A (NEW — E1)
- U+100000-10FFFD Supplementary PUA-B (NEW — E1)
Detection-only for PUA: PUA characters have NO standard ASCII mapping,
so `decodeUnicodeTags` leaves them unchanged. Detection alone is
sufficient — `scanForInjection` emits HIGH on any presence, regardless
of decoded content.
Function name `containsUnicodeTags` preserved for back-compat. All
existing call sites (injection-patterns.mjs:259, etc.) work unchanged.
Semantically the function is now "containsHiddenUnicode".
Tests: +21 cases in tests/lib/string-utils-hidden-unicode.test.mjs:
- 5 Tag-block regression guards
- 4 PUA-A range cases (start, just-inside, end, buried-in-ASCII)
- 3 PUA-B range cases
- 5 boundary cases (gap U+E0080-EFFFF, U+10FFFE noncharacter, emoji,
CJK, Latin Extended — all must be FALSE)
- 4 decodeUnicodeTags passthrough cases (PUA-A unchanged, PUA-B
unchanged, Tag block still decodes, mixed Tag+PUA)
Suite: 1596 → 1617 (+21). All green.
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.
