The output gate claimed LLM10 self-safety on the grounds that its patterns have
no nested quantifiers. True, and irrelevant: nesting is not what makes these
blow up. A run in front of a REQUIRED literal, reachable from a short anchor, is
enough -- crafted input repeats the anchor and never supplies the literal, so
every start position rescans the tail. Quadratic, not exponential, and the
max_scan_chars cap does not help: it bounds the input, and quadratic work on a
bounded input is still hours.
Measured, not argued. `<a:` x 100_000 took 23.4s in AUTOLINK_RE alone; the
composed gate on that payload took 458.7s, extrapolating to ~5.7 hours at the
1_000_000-char input the gate itself accepts. Size-matched ordinary prose runs
0.31s, so the separation is 18x-660x -- unlike the blob in the neighbouring
test, which is the *faster* side of prose and never exercised backtracking.
Two fixes, chosen per pattern rather than uniformly:
- active_content + lexicon JSON (15 runs): exclude the character that opens the
pattern's own anchor (`[` for markdown, `<` for tags), so a run cannot reach
past the next start position and the per-start costs telescope. Verified to
cost no recall: long URLs, long alt text, and `<` inside a quoted attribute
all still match. Bounding instead would have been linear too but wrong here --
the content is attacker-controlled, so padding past a bound would be a
one-line bypass of the EchoLeak class this table exists to catch.
- connstr egress (4 runs): bound the password at MAX_CONNSTR_VALUE. The
exclusion fix is unavailable -- the anchor character is `/` and passwords
containing `/` are the common case (measured: they match today). The residual
miss is a credential over 256 chars; a token that long is still caught by
egress:jwt-token.
hybrid-xss:script-tag had neither option: its run is the script BODY, which may
legitimately contain `<`. It now matches the opening tag and drops the
`</script>` requirement. That also closes a fail-open -- `<script>alert(1)`
unclosed was silently missed -- at the cost of flagging prose that merely
mentions `<script>`, now documented.
Found by the composed-gate test staying red after every individual scanner was
already linear: the lexicon's six html-obfuscation patterns were the remaining
813x. A per-scanner test alone would have shipped that.
662 passed (was 642), and faster than before the fix.
Output gate step 3 now runs scan_secret_egress over every decoded base64
blob's plaintext, not only scan_lexicon. A base64-wrapped credential that
formerly vanished (decode fed the lexicon, which has no secret patterns)
now surfaces as decoded:egress:* carrying the blob offset. Evidence stays
length-only, so the decoded finding never leaks the secret value.
Hex-wrapped secrets remain a documented honest-limit (entropy exposes
decoded plaintext for base64 only). README honest-limits + CLAUDE.md
Kontekst updated; 3 tests added (347 passed, was 344).
Close the EchoLeak wiring hole (CVE-2025-32711 class): markdown images/
links, reference definitions, autolinks, raw active HTML and data: URIs
now surface as report-only findings (active:*, OWASP LLM05) in
scan_output step 6, so screen_output and okf.import_bundle dispose of
them instead of admitting them with findings=[].
- new active_content.py: canonical home of the shared pattern table +
scan_active_content; neutralize refactored to import it (mutating API
and behavior unchanged, all neutralize tests pass as-is)
- images/links flagged only for absolute/protocol-relative URLs:
relative in-bundle links are legitimate wiki/OKF mechanism (principle 5)
- evidence carries defanged URLs only (hxxps://evil[.]example)
- EchoLeak vectors planted in both showcases; detach proofs cover them
- README export list + checklist step 6, CLAUDE.md context line updated
Suite: 321 -> 341 passed. Core invariant intact (dependencies=[]).
Pre-release hardening from an independent adversarial review; each fixed
test-first (failing test -> fix -> green). 214 tests pass.
- entropy (M1): decode-and-rescan now runs BEFORE false-positive suppression,
so an SRI/media-prefixed injection blob is still decoded and lexicon-rescanned.
Suppression gates only the entropy finding, never the decode.
- output/disposition (M3): the invisible-carrier invariant now holds on the
persist gate. scan_output flags zero-width/BIDI presence and disposition
treats those + lexicon:unicode-tags-present as any-tier carriers, so a carrier
in model output fails secure even under a trusted policy.
- contract (M2): assert_credential_allowlist catches a bare <PROVIDER>_KEY
(e.g. STRIPE_KEY) that the old regex silently missed (fail-open). Deliberately
broad: also flags PARTITION_KEY/SORT_KEY as loud, allowlistable FPs -- fail-loud
beats fail-silent for an isolation control.
- disposition (m6): guard runs decide inside its guarded block -> total
fail-closed even on a malformed report.
- output (m4): egress placeholder suppression anchors word markers (example,
todo, ...) to a word boundary, closing a fail-open where a real secret merely
containing such a word was suppressed.
Docs: CHANGELOG Security subsection; README honest-limit for lexicon dedup (m5,
documented tradeoff, not fixed).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HyRCQMocjZ6SmSQ6JidJ2k
Module 7 of the build order: the last gate before model output is persisted.
Composes scan_lexicon + scan_entropy over the emitted text, feeds each base64
blob entropy decoded back through the lexicon (decode-and-rescan → decoded:*
findings with blob offset), and adds the LLM02 secret/credential egress layer
(cloud/provider keys, PEM headers, DB conn-strings, JWT, labelled
password/secret/api-key assignments) with placeholder/varref FP-suppression.
Report-only (never mutates; neutralize is the separate opt-in mutator). Evidence
carries only a description + match length — never the secret value. Self-safe:
single input-size cap, linear egress patterns. PEM patterns use -{5} form so the
module itself never trips a secret scanner. 26 new tests; 108 green total.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HyRCQMocjZ6SmSQ6JidJ2k
