Adds a scope-hopping detector to the npm install gate. When a user
installs `@<scope>/<unscoped>`, the hook now emits a MEDIUM warning
on stderr (exit 0, never blocks) if:
- `<unscoped>` matches a popular npm package (POPULAR_NPM, ~80
names from knowledge/top-packages.json), AND
- `<scope>` is not on NPM_OFFICIAL_SCOPES (built-in 22 entries) or
on policy.json `supply_chain.allowed_scopes`.
Why: an attacker publishing `@evilcorp/lodash` cannot squat the bare
`lodash` name, but they can register an unrelated scope and rely on
typo or copy-paste to trick installs. NPM_OFFICIAL_SCOPES anchors the
known-good scopes (@types, @reduxjs, @nestjs, …) so legitimate
installs stay silent.
Implementation:
- `scanners/lib/supply-chain-data.mjs`: exports POPULAR_NPM,
NPM_OFFICIAL_SCOPES, and `checkScopeHop(name, extraAllowedScopes)` —
pure function, no policy/network dependency, fully unit-testable.
- `knowledge/typosquat-allowlist.json`: mirrors NPM_OFFICIAL_SCOPES as
`npm_official_scopes`. A doc-consistency assertion ensures the two
lists never drift.
- `hooks/scripts/pre-install-supply-chain.mjs`: imports checkScopeHop,
reads `supply_chain.allowed_scopes` from policy, and pushes a
warning before existing compromised/audit checks.
Tests:
- 9 new cases in tests/hooks/pre-install-supply-chain.test.mjs:
TP @evilcorp/lodash, TP @attacker/express, allowlist @types,
allowlist @reduxjs, allowlist @modelcontextprotocol, FP unscoped
name not in top-100, bare unscoped name, policy override, defensive
non-string input, NPM_OFFICIAL_SCOPES <-> typosquat-allowlist.json
consistency.
New policy-loader.mjs reads .llm-security/policy.json with deep-merge against
defaults that exactly match existing hardcoded values. Integrated into all 7 hooks:
- pre-prompt-inject-scan: injection.mode (env var still takes precedence)
- post-session-guard: trifecta.mode, window_size, long_horizon_window
- pre-edit-secrets: secrets.additional_patterns
- pre-bash-destructive: destructive.additional_blocked
- pre-write-pathguard: pathguard.additional_protected
- pre-install-supply-chain: supply_chain.additional_blocked_packages
- post-mcp-verify: mcp.volume_threshold_bytes, mcp.trusted_servers
Backward compatible: no policy file = identical behavior to v5.1.0.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
