feat(controls): B1 — custom semgrep detectors for 4 CRA controls #218

Merged
sharang merged 1 commits from feat/b1-cra-semgrep-rules into main 2026-07-21 12:31:20 +00:00
5 changed files with 338 additions and 44 deletions
+117
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@@ -0,0 +1,117 @@
# Custom semgrep rules for CRA controls that no off-the-shelf ruleset digs out.
# Each rule id is `cra-ai-<n>-<slug>` and is keyed back to its control via the
# `control-map` LUT (by rule-id suffix, so semgrep's path prefix on check_id does
# not matter). Detection here is deterministic; the grounded LLM judge downstream
# only confirms/refutes — it never detects. Keep patterns tight: a false positive
# that the judge refutes marks the whole finding a false positive.
rules:
# --- cra-ai-1: Secure-by-Default-Konfiguration -------------------------------
- id: cra-ai-1-flask-debug-enabled
languages: [python]
severity: WARNING
message: Flask app started with debug=True — ships an interactive debugger / code execution in production (secure-by-default violation).
metadata:
cwe: ["CWE-489: Active Debug Code"]
control: cra-ai-1
patterns:
- pattern: '$APP.run(..., debug=True, ...)'
- id: cra-ai-1-django-debug-true
languages: [python]
severity: WARNING
message: Django DEBUG = True — leaks stack traces / settings in production (secure-by-default violation).
metadata:
cwe: ["CWE-489: Active Debug Code"]
control: cra-ai-1
patterns:
- pattern: 'DEBUG = True'
- id: cra-ai-1-tls-verify-disabled
languages: [python]
severity: ERROR
message: TLS certificate verification disabled (verify=False) — defeats transport security by default.
metadata:
cwe: ["CWE-295: Improper Certificate Validation"]
control: cra-ai-1
patterns:
- pattern: 'requests.$M(..., verify=False, ...)'
- id: cra-ai-1-cors-wildcard
languages: [javascript, typescript]
severity: WARNING
message: CORS Access-Control-Allow-Origin set to "*" — opens the API to any origin by default.
metadata:
cwe: ["CWE-942: Permissive Cross-domain Policy with Untrusted Domains"]
control: cra-ai-1
patterns:
- pattern-either:
- pattern: '$RES.header("Access-Control-Allow-Origin", "*")'
- pattern: '$RES.setHeader("Access-Control-Allow-Origin", "*")'
# --- cra-ai-7: Starke Authentifizierung (weak password hashing) --------------
- id: cra-ai-7-weak-password-hash
languages: [python]
severity: ERROR
message: Password/secret hashed with a fast, broken digest (md5/sha1) — use a password KDF (bcrypt/scrypt/argon2).
metadata:
cwe: ["CWE-916: Use of Password Hash With Insufficient Computational Effort"]
control: cra-ai-7
patterns:
- pattern-either:
- pattern: 'hashlib.md5($PW)'
- pattern: 'hashlib.sha1($PW)'
- metavariable-regex:
metavariable: $PW
regex: '(?i).*(pass|pwd|secret|cred|token).*'
# --- cra-ai-10: Sitzungsmanagement (insecure session cookies) ----------------
- id: cra-ai-10-session-cookie-insecure
languages: [python]
severity: ERROR
message: Session cookie hardened flag explicitly disabled (Secure/HttpOnly = False) — session token exposed to theft.
metadata:
cwe: ["CWE-614: Sensitive Cookie in HTTPS Session Without 'Secure' Attribute"]
control: cra-ai-10
patterns:
- pattern-either:
- pattern: 'SESSION_COOKIE_SECURE = False'
- pattern: 'SESSION_COOKIE_HTTPONLY = False'
- id: cra-ai-10-express-cookie-insecure
languages: [javascript, typescript]
severity: ERROR
message: Express cookie set with secure/httpOnly = false — session token exposed to interception / XSS theft.
metadata:
cwe: ["CWE-614: Sensitive Cookie in HTTPS Session Without 'Secure' Attribute"]
control: cra-ai-10
patterns:
- pattern-either:
- pattern: '$RES.cookie($NAME, $VAL, {..., secure: false, ...})'
- pattern: '$RES.cookie($NAME, $VAL, {..., httpOnly: false, ...})'
# --- cra-ai-14: Speicher-Schutz / Data at Rest (weak cipher) -----------------
- id: cra-ai-14-python-weak-cipher
languages: [python]
severity: ERROR
message: Data-at-rest encrypted with a broken cipher/mode (ECB, DES, 3DES) — provides no real confidentiality.
metadata:
cwe: ["CWE-327: Use of a Broken or Risky Cryptographic Algorithm"]
control: cra-ai-14
patterns:
- pattern-either:
- pattern: 'AES.new($K, AES.MODE_ECB, ...)'
- pattern: 'DES.new(...)'
- pattern: 'DES3.new(...)'
- id: cra-ai-14-node-weak-cipher
languages: [javascript, typescript]
severity: ERROR
message: Data-at-rest encrypted with a broken cipher (DES / deprecated createCipher) — provides no real confidentiality.
metadata:
cwe: ["CWE-327: Use of a Broken or Risky Cryptographic Algorithm"]
control: cra-ai-14
patterns:
- pattern-either:
- pattern: 'crypto.createCipheriv("des-ecb", ...)'
- pattern: 'crypto.createCipheriv("des", ...)'
- pattern: 'crypto.createCipher(...)'
+54 -4
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@@ -44,10 +44,14 @@ impl<J: ControlJudge> ControlTriage<J> {
/// Triage one tool finding. `region` is the code around the finding, used as
/// the grounding evidence for the judge.
pub async fn triage(&self, finding: &Finding, region: &CandidateRegion) -> TriageOutcome {
let Some(cwe) = finding.cwe.as_deref() else {
return TriageOutcome::Unmapped;
};
let mapped = self.map.controls_for(&finding.scanner, cwe);
// Match by CWE (off-the-shelf findings) and/or rule id (our custom
// detectors, which carry no LUT-bound CWE). A finding with neither is
// simply unmapped.
let mapped = self.map.controls_for_finding(
&finding.scanner,
finding.cwe.as_deref(),
finding.rule_id.as_deref(),
);
if mapped.is_empty() {
return TriageOutcome::Unmapped;
}
@@ -162,6 +166,52 @@ mod tests {
assert_eq!(out, TriageOutcome::FalsePositive);
}
#[tokio::test]
async fn custom_rule_finding_without_cwe_is_confirmed() {
// A custom detector finding carries a rule id but no LUT-bound CWE; it must
// still map (by rule id) and confirm.
let mut specs = specs();
specs.insert(
"cra-ai-1".to_string(),
ControlCheckSpec {
control_id: "cra-ai-1".into(),
title: "Secure-by-Default".into(),
requirement: "Ship secure defaults".into(),
default_cwe: None,
severity: Severity::Medium,
},
);
let triage = ControlTriage::new(
StubJudge {
verdict: LlmVerdict {
violates: true,
snippet: "app.run(debug=True)".into(),
cwe: None,
confidence: 0.9,
},
},
ControlMap::cra().unwrap(),
specs,
);
let mut f = Finding::new(
"repo".into(),
"fp".into(),
"semgrep".into(),
ScanType::Sast,
"flask debug".into(),
"desc".into(),
Severity::Medium,
);
f.rule_id = Some("tmp.x.cra-ai-1-flask-debug-enabled".into()); // no cwe
let region = CandidateRegion {
file: "app.py".into(),
start_line: 1,
content: "app.run(debug=True)\n".into(),
};
let out = triage.triage(&f, &region).await;
assert_eq!(out, TriageOutcome::Confirmed(vec!["cra-ai-1".to_string()]));
}
#[tokio::test]
async fn unmapped_cwe_is_left_untagged() {
let triage = ControlTriage::new(
+36 -16
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@@ -1,4 +1,4 @@
use std::path::Path;
use std::path::{Path, PathBuf};
use compliance_core::models::{Finding, ScanType, Severity};
use compliance_core::traits::{ScanOutput, Scanner};
@@ -6,6 +6,30 @@ use compliance_core::CoreError;
use crate::pipeline::dedup;
/// Custom CRA-control detectors bundled into the binary and staged to a temp file
/// at scan time so semgrep can `--config` them alongside the auto ruleset. These
/// cover controls no off-the-shelf rule digs out (secure defaults, weak password
/// hashing, insecure session cookies, weak data-at-rest ciphers); each rule id is
/// keyed back to its control by the `control-map` LUT.
const CRA_RULES: &str = include_str!("../../rules/cra_semgrep.yaml");
/// Write the bundled CRA rules to a stable temp path (atomic: unique tmp +
/// rename). Returns `None` on failure — the scan then runs with auto rules only.
async fn stage_cra_rules() -> Option<PathBuf> {
let dir = std::env::temp_dir();
let path = dir.join("compliance-cra-semgrep.yaml");
let tmp = dir.join(format!("compliance-cra-semgrep.{}.tmp", std::process::id()));
if let Err(e) = tokio::fs::write(&tmp, CRA_RULES).await {
tracing::warn!(error = %e, "failed to stage custom CRA semgrep rules; using auto rules only");
return None;
}
if let Err(e) = tokio::fs::rename(&tmp, &path).await {
tracing::warn!(error = %e, "failed to stage custom CRA semgrep rules; using auto rules only");
return None;
}
Some(path)
}
pub struct SemgrepScanner;
impl Scanner for SemgrepScanner {
@@ -19,21 +43,17 @@ impl Scanner for SemgrepScanner {
#[tracing::instrument(skip_all)]
async fn scan(&self, repo_path: &Path, repo_id: &str) -> Result<ScanOutput, CoreError> {
let output = tokio::time::timeout(
std::time::Duration::from_secs(600),
tokio::process::Command::new("semgrep")
.args([
"--config=auto",
"--json",
"--quiet",
"--max-memory",
"500",
"--jobs",
"1",
])
.arg(repo_path)
.output(),
)
let cra_rules = stage_cra_rules().await;
let mut command = tokio::process::Command::new("semgrep");
command.arg("--config=auto");
if let Some(path) = &cra_rules {
command.arg(format!("--config={}", path.display()));
}
command
.args(["--json", "--quiet", "--max-memory", "500", "--jobs", "1"])
.arg(repo_path);
let output = tokio::time::timeout(std::time::Duration::from_secs(600), command.output())
.await
.map_err(|_| CoreError::Scanner {
scanner: "semgrep".to_string(),
+53 -12
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@@ -5,9 +5,21 @@
{
"control": "cra-ai-1",
"title": "Secure-by-Default-Konfiguration",
"scans": [],
"note": "code-checkable but no off-the-shelf tool digs it out — author a detector (custom semgrep rule / check)",
"status": "needs_tooling"
"scans": [
{
"tool": "semgrep",
"scan_type": "sast",
"cwe": [],
"rules": [
"cra-ai-1-flask-debug-enabled",
"cra-ai-1-django-debug-true",
"cra-ai-1-tls-verify-disabled",
"cra-ai-1-cors-wildcard"
]
}
],
"note": null,
"status": "covered"
},
{
"control": "cra-ai-2",
@@ -47,9 +59,18 @@
{
"control": "cra-ai-7",
"title": "Starke Authentifizierung",
"scans": [],
"note": "code-checkable but no off-the-shelf tool digs it out — author a detector (custom semgrep rule / check)",
"status": "needs_tooling"
"scans": [
{
"tool": "semgrep",
"scan_type": "sast",
"cwe": [],
"rules": [
"cra-ai-7-weak-password-hash"
]
}
],
"note": null,
"status": "covered"
},
{
"control": "cra-ai-8",
@@ -100,9 +121,19 @@
{
"control": "cra-ai-10",
"title": "Sitzungsmanagement",
"scans": [],
"note": "code-checkable but no off-the-shelf tool digs it out — author a detector (custom semgrep rule / check)",
"status": "needs_tooling"
"scans": [
{
"tool": "semgrep",
"scan_type": "sast",
"cwe": [],
"rules": [
"cra-ai-10-session-cookie-insecure",
"cra-ai-10-express-cookie-insecure"
]
}
],
"note": null,
"status": "covered"
},
{
"control": "cra-ai-11",
@@ -138,9 +169,19 @@
{
"control": "cra-ai-14",
"title": "Speicher-Schutz (Data at Rest)",
"scans": [],
"note": "code-checkable but no off-the-shelf tool digs it out — author a detector (custom semgrep rule / check)",
"status": "needs_tooling"
"scans": [
{
"tool": "semgrep",
"scan_type": "sast",
"cwe": [],
"rules": [
"cra-ai-14-python-weak-cipher",
"cra-ai-14-node-weak-cipher"
]
}
],
"note": null,
"status": "covered"
},
{
"control": "cra-ai-15",
+69 -3
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@@ -66,6 +66,14 @@ pub struct ControlMap {
const CRA_MAP_JSON: &str = include_str!("../data/cra_control_map.json");
/// Whether an authored rule id `bound` matches a scanner's emitted rule id
/// `actual`. semgrep prefixes local-rule check_ids with a path
/// (`tmp.compliance-cra-semgrep.cra-ai-1-flask-debug-enabled`), so match the final
/// id segment rather than requiring exact equality.
fn rule_id_matches(bound: &str, actual: &str) -> bool {
actual == bound || actual.ends_with(&format!(".{bound}"))
}
impl ControlMap {
/// Load the built-in CRA control map (the embedded, authored LUT).
pub fn cra() -> Result<Self, MapError> {
@@ -80,12 +88,28 @@ impl ControlMap {
/// Controls whose bindings include the given `tool` + `cwe` — used to attach a
/// raw tool finding back to the control(s) it's evidence for.
pub fn controls_for(&self, tool: &str, cwe: &str) -> Vec<&ControlEntry> {
self.controls_for_finding(tool, Some(cwe), None)
}
/// Controls a tool finding is evidence for, matched by CWE and/or the specific
/// rule id that fired. Off-the-shelf findings bind by CWE; our custom detectors
/// bind by rule id (precise — a broad CWE would over-attribute and then the
/// grounded judge could drop a genuine finding as a control false positive).
pub fn controls_for_finding(
&self,
tool: &str,
cwe: Option<&str>,
rule_id: Option<&str>,
) -> Vec<&ControlEntry> {
self.controls
.iter()
.filter(|c| {
c.scans
.iter()
.any(|s| s.tool == tool && s.cwe.iter().any(|w| w == cwe))
c.scans.iter().any(|s| {
s.tool == tool
&& (cwe.is_some_and(|w| s.cwe.iter().any(|x| x == w))
|| rule_id
.is_some_and(|r| s.rules.iter().any(|b| rule_id_matches(b, r))))
})
})
.collect()
}
@@ -160,4 +184,46 @@ mod tests {
assert!(s.needs_tooling > 0);
assert!(s.not_code_checkable > 0);
}
#[test]
fn rule_id_matching_handles_semgrep_path_prefix() {
let bound = "cra-ai-1-flask-debug-enabled";
assert!(rule_id_matches(bound, bound)); // exact
assert!(rule_id_matches(
bound,
"tmp.compliance-cra-semgrep.cra-ai-1-flask-debug-enabled"
)); // semgrep path prefix
assert!(!rule_id_matches(
bound,
"cra-ai-1-flask-debug-enabled-extra"
)); // not a suffix segment
assert!(!rule_id_matches(
bound,
"python.lang.security.exec-detected"
)); // unrelated
}
#[test]
fn custom_rule_finding_attaches_to_control_by_rule_id() {
let map = ControlMap::cra().unwrap();
// cra-ai-1 is now tool-covered by custom rules.
assert_eq!(map.coverage("cra-ai-1").unwrap().status, Coverage::Covered);
// A prefixed check_id still maps back to cra-ai-1 by rule id.
let hits =
map.controls_for_finding("semgrep", None, Some("tmp.x.cra-ai-1-tls-verify-disabled"));
assert!(hits.iter().any(|c| c.control == "cra-ai-1"));
}
#[test]
fn custom_rule_controls_do_not_bind_by_broad_cwe() {
let map = ControlMap::cra().unwrap();
// cra-ai-1 rules emit CWE-489 in metadata, but the LUT binds by rule id
// only (cwe: []) — so a stray CWE-489 finding must NOT attach to it.
assert!(map.controls_for("semgrep", "CWE-489").is_empty());
// The CWE path for off-the-shelf findings is unchanged.
assert!(map
.controls_for("semgrep", "CWE-798")
.iter()
.any(|c| c.control == "cra-ai-8"));
}
}