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Rule Reference

SEC493lintai-ai-securitygovernancehardeningpreviewclaude_settingswarn

Claude settings: shared bunx Bash permissions

Claude settings permissions allow `Bash(bunx ...)` in a shared committed config

Public lane
governance
Category
hardening
Provider
lintai-ai-security
Scope
per-file
Surface
claude_settings
Tier
preview
Severity
warn
Confidence
high
Detection
structural
Remediation
message only
How to read this lane

Shared authority and workflow policy review.

How to read this category

Least-privilege, provenance, or operational hygiene signal.

Activation Model

Preset Activation

These presets explain where this rule appears in the product experience.

governancesidecar lane
claudesurface preset

Lifecycle

Stable Lifecycle Contract

State

stable

Graduation rationale

Checks shared committed Claude settings for exact `Bash(bunx ...)` mutable package-runner authority.

Deterministic signal basis

ClaudeSettingsSignals exact permission detection for `Bash(bunx ...)` entries inside permissions.allow.

Malicious corpus
claude-settings-npm-exec-bunx-permissions
Benign corpus
claude-settings-npm-exec-bunx-specific-safe
structured evidence required remediation reviewed
Canonical note

Structural preview rule; deterministic today, but the preview contract may still evolve.

Nearby Signals

Related Rules

SEC385Claude settings: shared git push permissionsClaude settings permissions allow `Bash(git push)` in a shared committed configgovernancehardeningclaude_settings
SEC386Claude settings: shared git checkout permissionsClaude settings permissions allow `Bash(git checkout:*)` in a shared committed configgovernancehardeningclaude_settings
SEC387Claude settings: shared git commit permissionsClaude settings permissions allow `Bash(git commit:*)` in a shared committed configgovernancehardeningclaude_settings
SEC388Claude settings: shared git stash permissionsClaude settings permissions allow `Bash(git stash:*)` in a shared committed configgovernancehardeningclaude_settings
SEC399Claude settings: shared npx Bash permissionsClaude settings permissions allow `Bash(npx ...)` in a shared committed configgovernancehardeningclaude_settings
SEC406Claude settings: shared git add permissionsClaude settings permissions allow `Bash(git add:*)` in a shared committed configgovernancehardeningclaude_settings

SEC493 / CLAUDE-BUNX-PERMISSION ​

SEC493 flags shared Claude settings when permissions.allow grants Bash(bunx ...).

Why It Matters ​

bunx resolves and executes packages through a mutable runner path. Shared Claude settings should not quietly make that a default team capability.

Trigger Shape ​

The rule triggers only when all of these are true:

  • the file is a detected Claude settings surface
  • the path is not fixture-like
  • permissions.allow contains a string that starts with Bash(bunx

Clean Cases ​

These stay clean:

  • non-bunx commands such as Bash(bun run lint)
  • settings without Bash(bunx ...)
  • fixture-like examples under test or fixture paths

Example Trigger ​

json
{
  "permissions": {
    "allow": ["Bash(bunx prettier:*)", "Read(*)"]
  }
}

Safer Example ​

json
{
  "permissions": {
    "allow": ["Bash(bun run lint)", "Read(*)"]
  }
}

How To Fix ​

Replace shared Bash(bunx ...) permissions with a pinned wrapper or a narrower reviewed command permission that does not grant mutable package execution by default.