# Staff Security Engineer — Review Round 4

**Branch:** `colonyos/when_you_output_followups_in_the_thread_on_slack_a938599349`
**PRD:** `cOS_prds/20260331_190640_prd_you_are_a_code_assistant_working_on_behalf_of_the_engineering_team_the_following.md`

## Checklist

### Completeness
- [x] All functional requirements from the PRD are implemented (FR-1 through FR-5)
- [x] All tasks in the task file are marked complete (1.0–6.0)
- [x] No placeholder or TODO code remains

### Quality
- [x] All 135 tests pass (test_sanitize.py: 50 tests, test_slack_formatting.py: 85 tests)
- [x] Code follows existing project conventions
- [x] No unnecessary dependencies added (pure string operations + `re`)
- [x] No unrelated changes included

### Safety
- [x] No secrets or credentials in committed code
- [x] No destructive database operations
- [x] Error handling present for failure cases (try/except on cost/duration parsing, empty-string guards, 3-tier fallback)

## Security Assessment

### Round 3 Findings — Verified Fixed

1. **`_SLACK_BARE_LINK_RE` expanded to arbitrary URI schemes** — The regex was `https?://` only; now matches `[a-zA-Z][a-zA-Z0-9+.-]*://|mailto:`, closing the gap where bare `<mailto:...>` and `<slack://...>` links could pass through unsanitized. Verified with new tests `test_neutralizes_bare_mailto_link` and `test_neutralizes_bare_slack_protocol_link`.

2. **Audit logging added** — `sanitize_for_slack()` now emits a `logger.debug()` call when content is actually neutralized (`result != original`), and stays silent for clean content. Verified with `test_audit_log_on_neutralization` and `test_no_audit_log_for_clean_content`.

3. **Phase header truncation consistency** — Now uses `_SLACK_TASK_DESC_MAX` (72) constant instead of hardcoded 60/57. Consistent with all other truncation sites.

### Sanitization Chain — Complete Verification

Double-sanitization (`sanitize_untrusted_content()` → `sanitize_for_slack()`) is applied at all untrusted content ingress points:

| Location | Content Type | Sanitized |
|---|---|---|
| orchestrator.py:875 | phase_header task description | ✅ |
| `_format_task_outline_note()` | task descriptions | ✅ |
| `_format_task_list_with_descriptions()` | task descriptions | ✅ |
| `_extract_review_findings_summary()` — FINDINGS path | review finding text | ✅ |
| `_extract_review_findings_summary()` — SYNTHESIS path | synthesis text | ✅ |
| `_extract_review_findings_summary()` — fallback path | first line of review | ✅ |

### Injection Vectors — Coverage Matrix

| Vector | Covered | Regex |
|---|---|---|
| `@here` / `@channel` / `@everyone` | ✅ | `_SLACK_MENTION_RE` (case-insensitive) |
| `<!here>` / `<!channel\|...>` / `<!everyone>` | ✅ | `_SLACK_MENTION_RE` |
| `<@U...>` / `<@B...>` / `<@W...>` user/bot mentions | ✅ | `_SLACK_MENTION_RE` |
| `<scheme://url\|display>` link phishing (any scheme) | ✅ | `_SLACK_LINK_INJECTION_RE` |
| `<scheme://url>` bare links (any scheme) | ✅ | `_SLACK_BARE_LINK_RE` |
| `<mailto:...\|display>` | ✅ | `_SLACK_LINK_INJECTION_RE` |
| `<mailto:...>` bare | ✅ | `_SLACK_BARE_LINK_RE` |
| `*bold*` / `_italic_` / `~strike~` / `` `code` `` formatting | ✅ | `_SLACK_MRKDWN_CHARS_RE` |
| `> blockquote` at line start | ✅ | Zero-width space prefix |
| `<xml>` tag injection | ✅ | `sanitize_untrusted_content()` (upstream) |

### Truncation — Defense in Depth

- `_truncate_slack_message()` applied at all 3 formatting function return sites (`_format_task_outline_note`, `_format_implement_result_note`, `_format_review_round_note`)
- 3,000-char cap verified by pathological-input tests (50 tasks × 100-char descriptions, 10 reviewers × 20 findings)
- Per-item truncation: 72 chars per task description, 80 chars per finding — limits information leakage from verbose review text

---

VERDICT: approve

FINDINGS:
- [src/colonyos/orchestrator.py:1502-1508]: `_extract_review_findings_summary` blank-line handling (`continue` on empty lines within FINDINGS section) is now correct — blank lines between findings don't stop collection. However, the parser still has a loose state machine: a line that starts with `-` but not `- ` (e.g., `--- separator ---`) would not match `stripped.startswith("- ")` and would trigger the `break` via the `not stripped.startswith("-")` check. This is correct behavior (stops at non-finding content) but worth noting for future reviewers.
- [src/colonyos/orchestrator.py:420-428]: `_format_task_list_with_descriptions` silently swallows `ValueError`/`TypeError` on cost/duration formatting. Adding `logger.debug` would cost nothing and aid future debugging — but this is a style nit, not a security concern.

SYNTHESIS:
This implementation is production-ready from a security perspective. All three non-blocking findings from round 3 have been addressed: the bare-link regex now covers arbitrary URI schemes (not just http/https), audit logging fires when content is neutralized, and the phase header truncation uses the named constant consistently. The sanitization architecture is sound — `sanitize_untrusted_content()` strips XML injection at the outer boundary, `sanitize_for_slack()` neutralizes Slack-specific injection vectors (mentions, links, mrkdwn formatting, blockquotes), and the ordering is correct and consistently applied at all 7 ingress points. The truncation layer provides secondary defense against information leakage. The 135-test suite includes dedicated integration tests verifying the sanitization chain end-to-end through the formatting functions. No remaining security concerns warrant blocking. Ship it.
