# Staff Security Engineer — Round 3 Review

**Branch:** `colonyos/when_you_output_followups_in_the_thread_on_slack_a938599349`
**Tests:** 131 passing, 0 failing
**Diff:** +1,300 / -23 lines across 6 production/test files + 2 review artifacts

## Checklist

### Completeness
- [x] FR-1: Task completion messages include sanitized description
- [x] FR-2: Task outline uses bullet formatting with overflow
- [x] FR-3: Task result summary includes descriptions with cost/duration
- [x] FR-4: Review round messages include condensed finding summaries
- [x] FR-5: Double sanitization (`sanitize_untrusted_content()` → `sanitize_for_slack()`) at all untrusted content ingress points
- [x] All tasks complete, no TODO/placeholder code

### Quality
- [x] 131 tests pass (70 new sanitize + formatting tests)
- [x] Named constants replace magic numbers
- [x] Truncation applied intrinsically in formatters

### Safety Assessment

**Sanitization architecture is correct.** Every untrusted content path applies `sanitize_untrusted_content()` (XML tag stripping) then `sanitize_for_slack()` (mrkdwn escaping + mention/link neutralization). I verified all 7 call sites in orchestrator.py:
- Line 875: phase_header task description
- Line 1363: task outline descriptions
- Line 1421: task result descriptions
- Line 1557: review findings extraction
- Line 1576: synthesis extraction
- Line 1585: fallback first-line extraction
- Line 964: git commit message (correctly uses only `sanitize_untrusted_content`, no Slack escaping needed)

**Mention injection is covered.** The `_SLACK_MENTION_RE` regex handles `@here`, `@channel`, `@everyone`, `<!here>`, `<!channel|...>`, `<!everyone>`, `<@U...>`, `<@B...>`, `<@W...>` with case-insensitive matching. All tested.

**Link injection is covered.** `_SLACK_LINK_INJECTION_RE` uses a generic URI scheme pattern (`[a-zA-Z][a-zA-Z0-9+.-]*://`) plus explicit `mailto:` — covers http, https, slack, ftp, and arbitrary schemes with display text. Bare links handled by `_SLACK_BARE_LINK_RE`.

**Truncation provides defense-in-depth.** 3,000-char cap applied via `_truncate_slack_message()` at the output of every formatter. Individual descriptions capped at 72 chars, findings at 80 chars. This limits information leakage surface.

**No secrets in committed code.** Verified the diff contains no API keys, tokens, or credentials.

## Findings (Non-Blocking)

### Low Priority

1. **`_SLACK_BARE_LINK_RE` only covers `https?://`** — A bare `<mailto:user@corp.com>` (without display text) would pass through unsanitized by `sanitize_for_slack()`. The `_SLACK_LINK_INJECTION_RE` correctly handles `<mailto:...|text>` with display text, but the bare form isn't caught. Practical risk is low: Slack auto-links bare emails regardless, and `sanitize_untrusted_content()` strips XML-like tags upstream. But for completeness, `_SLACK_BARE_LINK_RE` could be broadened to `<([a-zA-Z][a-zA-Z0-9+.-]*://[^>]+|mailto:[^>]+)>`.

2. **No audit logging when sanitization neutralizes content.** When `sanitize_for_slack()` replaces mentions with `[mention]` or defangs links, there's no log trace. Compare with `strip_slack_links()` which logs stripped URLs at DEBUG level. Adding similar logging would aid in detecting injection attempts or debugging false positives.

3. **`_extract_review_findings_summary` trusts the structure of LLM output.** The parser collects lines after `FINDINGS:` that start with `- `. A malicious or confused LLM could emit `FINDINGS:` followed by hundreds of lines, but this is mitigated by `max_findings=2` default and per-finding truncation. Acceptable.

---

VERDICT: approve

FINDINGS:
- [src/colonyos/sanitize.py]: `_SLACK_BARE_LINK_RE` only covers http/https — bare `<mailto:...>` without display text not caught. Low risk due to upstream XML sanitizer.
- [src/colonyos/sanitize.py]: No audit logging when mentions/links are neutralized by `sanitize_for_slack()`. Would aid injection detection but not a security gap.

SYNTHESIS:
The implementation is secure and production-ready. All identified injection vectors from Rounds 1 and 2 remain closed. The double-sanitization pattern (`sanitize_untrusted_content()` → `sanitize_for_slack()`) is applied consistently at all 7 untrusted content ingress points. Mention neutralization covers all Slack mention syntaxes including user/bot/workspace mentions. Link injection handling covers arbitrary URI schemes with display text. The 3,000-char truncation cap and per-field length limits provide defense-in-depth against both information leakage and message flooding. The two remaining observations (bare mailto links, audit logging) are low-priority hardening items that do not affect the security posture of this change.
