mcp-server-semgrep/semgrep-rules/javascript/express/security/audit/res-render-injection.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: res-render-injection
  message: >-
    User controllable data `$REQ` enters `$RES.render(...)` this can lead to the loading
    of other HTML/templating pages that they may not be authorized to render. An attacker
    may attempt to use directory traversal techniques e.g. `../folder/index` to access other
    HTML pages on the file system. Where possible, do not allow users to define what should be 
    loaded in $RES.render or use an allow list for the existing application.
  options:
    interfile: true
  metadata:
    interfile: true
    owasp:
    - A01:2021 - Broken Access Control
    cwe:
    - 'CWE-706: Use of Incorrectly-Resolved Name or Reference'
    category: security
    technology:
    - express
    references:
    - http://expressjs.com/en/4x/api.html#res.render
    subcategory:
    - vuln
    likelihood: MEDIUM
    impact: MEDIUM
    confidence: MEDIUM
  languages:
  - javascript
  - typescript
  severity: WARNING
  mode: taint
  pattern-sources:
  - patterns:
    - pattern-either:
      - pattern-inside: function ... ($REQ, $RES) {...}
      - pattern-inside: function ... ($REQ, $RES, $NEXT) {...}
      - patterns:
        - pattern-either:
          - pattern-inside: $APP.$METHOD(..., function $FUNC($REQ, $RES) {...})
          - pattern-inside: $APP.$METHOD(..., function $FUNC($REQ, $RES, $NEXT) {...})
        - metavariable-regex:
            metavariable: $METHOD
            regex: ^(get|post|put|head|delete|options)$
    - pattern-either:
      - pattern: $REQ.query
      - pattern: $REQ.body
      - pattern: $REQ.params
      - pattern: $REQ.cookies
      - pattern: $REQ.headers
  - patterns:
    - pattern-either:
      - pattern-inside: |
          ({ $REQ }: Request,$RES: Response, $NEXT: NextFunction) =>
          {...}
      - pattern-inside: |
          ({ $REQ }: Request,$RES: Response) => {...}
    - focus-metavariable: $REQ
    - pattern-either:
      - pattern: params
      - pattern: query
      - pattern: cookies
      - pattern: headers
      - pattern: body
  pattern-sinks:
  - patterns:
    - pattern-either:
      - pattern: $RES.render($SINK, ...)
    - focus-metavariable: $SINK