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* feat: Enhance data exfiltration detection with source sensitivity gating for cookies and headers * feat: Implement cross-file data exfiltration detection with parameter-specific gate filters * feat: Add calibration tests and refine DATA_EXFIL severity scoring logic * feat: Introduce per-detector configuration for data exfiltration suppression * feat: Enhance DATA_EXFIL findings with destination field tracking in diagnostics and SARIF output * feat: Add tainted body and URL handling for data exfiltration detection * feat: Add integration tests and fixtures for DATA_EXFIL and SSRF detection in Go * feat: Add Java integration tests and fixtures for DATA_EXFIL detection across multiple HTTP clients * feat: Add synthetic externals handling for closure-captured variables in SSA * feat: Implement closure-based suppression for resource leak findings * feat: Add regression guards for shell-injection and taint propagation in for-of destructure patterns * feat: Implement constructor cap narrowing for data exfiltration detection in HTTP request builders * feat: Add gated sinks for data exfiltration detection in C and C++ using curl_easy_setopt * feat: Implement DATA_EXFIL cap parity for backwards analysis and add integration tests * feat: Add data exfiltration sinks for various languages and enhance documentation * refactor: Simplify formatting and improve readability in various files * refactor: Improve readability by simplifying conditional statements and adding clippy linting * docs: Update CHANGELOG and comments for data exfiltration features and configuration * docs: Clarify configuration instructions for data exfiltration trusted destinations * docs: Enhance comments for evidence routing logic in data exfiltration
82 lines
4.6 KiB
Markdown
82 lines
4.6 KiB
Markdown
# Detectors
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Nyx ships four independent detector families. They run together in `--mode full`, the default. Findings are merged, deduplicated, ranked, and printed in one result set.
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| Family | Rule prefix | Looks at | What it finds |
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|---|---|---|---|
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| [Taint analysis](detectors/taint.md) | `taint-*` | Cross-file dataflow | Unsanitized data flowing source to sink |
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| [CFG structural](detectors/cfg.md) | `cfg-*` | Per-function control flow | Auth gaps, unguarded sinks, error fallthrough, resource release on all paths |
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| [State model](detectors/state.md) | `state-*` | Per-function state lattice | Use-after-close, double-close, leaks, unauthenticated access |
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| [AST patterns](detectors/patterns.md) | `<lang>.<cat>.<name>` | Tree-sitter structural match | Banned APIs, weak crypto, dangerous constructs |
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The taint family is split into cap-specific rule classes when a sink callee carries multiple vulnerability classes:
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| Rule id | Cap | Surface |
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|---|---|---|
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| `taint-unsanitised-flow` | every cap except `data_exfil` and `unauthorized_id` | Default taint flow class |
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| `taint-data-exfiltration` | `data_exfil` | Sensitive data flowing into the payload of an outbound network request (body / headers / json on `fetch`, body on `XMLHttpRequest.send`). Distinct from SSRF: the destination is fixed but attacker-influenced bytes leave the process. |
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| `rs.auth.missing_ownership_check.taint` | `unauthorized_id` | Rust auth subsystem fold-in; see [auth.md](auth.md). |
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A single call site can fire several of these at once when it carries multiple gates — `fetch(taintedUrl, {body: tainted})` produces both an SSRF finding (URL flow) and a `taint-data-exfiltration` finding (body flow), each with its own cap mask rather than a conflated union.
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For Rust auth-specific rules (`rs.auth.*`), see [auth.md](auth.md).
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## How they combine
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In `--mode full`:
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1. **Taint and AST can both fire on one line.** If `eval(userInput)` triggers both `js.code_exec.eval` (AST) and `taint-unsanitised-flow` (taint), both are kept with distinct rule IDs. The taint finding ranks higher because of the analysis-kind bonus.
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2. **State supersedes CFG on resource leaks.** When `state-resource-leak` and `cfg-resource-leak` fire at the same location, the CFG one is dropped.
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3. **Exact duplicates are removed.** Same line, column, rule ID, severity → one finding.
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## Modes
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| Mode | Active detectors |
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| `full` (default) | All four |
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| `ast` | AST patterns only |
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| `cfg` | Taint + CFG + State (no AST patterns) |
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| `taint` | Taint + State |
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## Attack-surface ranking
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Every finding gets a deterministic score. Findings are sorted by descending score by default. Disable with `--no-rank` or `output.attack_surface_ranking = false`.
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```
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score = severity_base + analysis_kind + evidence_strength + state_bonus - validation_penalty
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```
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| Component | Values |
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| Severity base | High=60, Medium=30, Low=10 |
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| Analysis kind | taint=+10, taint-data-exfiltration=+7, state=+8, cfg with evidence=+5, cfg without evidence=+3, ast=+0 |
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| Evidence strength | +1 per evidence item up to 4; +2 to +6 for source kind |
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| State bonus | use-after-close / unauthed=+6, double-close=+3, must-leak=+2, may-leak=+1 |
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| Validation penalty | -5 if path-validated |
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DATA_EXFIL is calibrated below other taint classes by design. Severity is High only when the source carries credential / session material (cookies, env vars); other Sensitive sources (request headers, file system, database, caught exception) downgrade to Medium. Confidence is capped at Medium and only fires Medium when the abstract / symbolic domain corroborates a concrete string body reaching the outbound payload; otherwise it falls to Low. A guarded flow (`path_validated`) drops a confidence tier. The intent is to seat data-exfiltration findings below SSRF / SQLi / command-injection but above informational AST patterns.
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Source-kind contributions (taint only):
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| Source | Bonus |
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| User input (`req.body`, `argv`, `stdin`, `form`, `query`, `params`) | +6 |
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| Environment (`env::var`, `getenv`, `process.env`) | +5 |
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| Unknown | +4 |
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| File system | +3 |
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| Database | +2 |
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Approximate score ranges:
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| Finding type | Score |
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| High taint with user input | 76 to 81 |
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| High state (use-after-close) | ~74 |
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| High CFG structural | 63 to 68 |
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| High DATA_EXFIL (cookie / env source, body confirmed) | ~76 |
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| Medium taint with env source | 45 to 50 |
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| Medium DATA_EXFIL (header / fs / db / caught-exception source) | 40 to 45 |
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| Medium state (resource leak) | ~40 |
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| Low AST-only pattern | ~10 |
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For the engine's runtime model (passes, summaries, SCC fixed-point), see [how-it-works.md](how-it-works.md).
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