mcp-server-semgrep/semgrep-rules/python/lang/security/dangerous-subprocess-use.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: dangerous-subprocess-use
  mode: taint
  options:
    symbolic_propagation: true
  pattern-sources:
  - patterns:
    - pattern-either:
      - patterns:
        - pattern-either:
          - pattern: flask.request.form.get(...)
          - pattern: flask.request.form[...]
          - pattern: flask.request.args.get(...)
          - pattern: flask.request.args[...]
          - pattern: flask.request.values.get(...)
          - pattern: flask.request.values[...]
          - pattern: flask.request.cookies.get(...)
          - pattern: flask.request.cookies[...]
          - pattern: flask.request.stream
          - pattern: flask.request.headers.get(...)
          - pattern: flask.request.headers[...]
          - pattern: flask.request.data
          - pattern: flask.request.full_path
          - pattern: flask.request.url
          - pattern: flask.request.json
          - pattern: flask.request.get_json()
          - pattern: flask.request.view_args.get(...)
          - pattern: flask.request.view_args[...]
          - patterns:
            - pattern-inside: |
                @$APP.route(...)
                def $FUNC(..., $ROUTEVAR, ...):
                  ...
            - focus-metavariable: $ROUTEVAR
      - patterns:
        - pattern-inside: |
            def $FUNC(request, ...):
              ...
        - pattern-either:
          - pattern: request.$PROPERTY.get(...)
          - pattern: request.$PROPERTY[...]
      - patterns:
        - pattern-either:
          - pattern-inside: |
              @rest_framework.decorators.api_view(...)
              def $FUNC($REQ, ...):
                ...
          - patterns:
            - pattern-either:
              - pattern-inside: |
                  class $VIEW(..., rest_framework.views.APIView, ...):
                    ...
              - pattern-inside: |
                  class $VIEW(..., rest_framework.generics.GenericAPIView, ...):
                    ...                              
            - pattern-inside: |
                def $METHOD(self, $REQ, ...):
                  ...
            - metavariable-regex:
                metavariable: $METHOD
                regex: (get|post|put|patch|delete|head)
        - pattern-either:
          - pattern: $REQ.POST.get(...)
          - pattern: $REQ.POST[...]
          - pattern: $REQ.FILES.get(...)
          - pattern: $REQ.FILES[...]
          - pattern: $REQ.DATA.get(...)
          - pattern: $REQ.DATA[...]
          - pattern: $REQ.QUERY_PARAMS.get(...)
          - pattern: $REQ.QUERY_PARAMS[...]
          - pattern: $REQ.data.get(...)
          - pattern: $REQ.data[...]
          - pattern: $REQ.query_params.get(...)
          - pattern: $REQ.query_params[...]
          - pattern: $REQ.content_type
          - pattern: $REQ.content_type
          - pattern: $REQ.stream
          - pattern: $REQ.stream
      - patterns:
        - pattern-either:
          - pattern-inside: |
              class $SERVER(..., http.server.BaseHTTPRequestHandler, ...):
                ...
          - pattern-inside: |
              class $SERVER(..., http.server.StreamRequestHandler, ...):
                ...
          - pattern-inside: |
              class $SERVER(..., http.server.DatagramRequestHandler, ...):
                ...
        - pattern-either:
          - pattern: self.requestline
          - pattern: self.path
          - pattern: self.headers[...]
          - pattern: self.headers.get(...)
          - pattern: self.rfile
      - patterns:
        - pattern-inside: |
            @pyramid.view.view_config( ... )
            def $VIEW($REQ):
              ...
        - pattern: $REQ.$ANYTHING
        - pattern-not: $REQ.dbsession
  pattern-sinks:
  - patterns:
    - pattern-either:
      - patterns:
        - pattern-not: subprocess.$FUNC("...", ...)
        - pattern-not: subprocess.$FUNC(["...",...], ...)
        - pattern-not: subprocess.$FUNC(("...",...), ...)
        - pattern-not: subprocess.CalledProcessError(...)
        - pattern-not: subprocess.SubprocessError(...)
        - pattern: subprocess.$FUNC($CMD, ...)
      - patterns:
        - pattern-not: subprocess.$FUNC("=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c","...",...)
        - pattern: subprocess.$FUNC("=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c", $CMD)
      - patterns:
        - pattern-not: subprocess.$FUNC(["=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c","...",...],...)
        - pattern-not: subprocess.$FUNC(("=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c","...",...),...)
        - pattern-either:
          - pattern: subprocess.$FUNC(["=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c", $CMD], ...)
          - pattern: subprocess.$FUNC(("=~/(sh|bash|ksh|csh|tcsh|zsh)/","-c", $CMD), ...)
      - patterns:
        - pattern-not: subprocess.$FUNC("=~/(python)/","...",...)
        - pattern: subprocess.$FUNC("=~/(python)/", $CMD)
      - patterns:
        - pattern-not: subprocess.$FUNC(["=~/(python)/","...",...],...)
        - pattern-not: subprocess.$FUNC(("=~/(python)/","...",...),...)
        - pattern-either:
          - pattern: subprocess.$FUNC(["=~/(python)/", $CMD],...)
          - pattern: subprocess.$FUNC(("=~/(python)/", $CMD),...)
    - focus-metavariable: $CMD
  message: >-
    Detected subprocess function '$FUNC' with user controlled data. A malicious actor
    could leverage this to perform command injection.
    You may consider using 'shlex.escape()'.
  metadata:
    owasp:
    - A01:2017 - Injection
    - A03:2021 - Injection
    cwe:
    - "CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')"
    asvs:
      section: 'V5: Validation, Sanitization and Encoding Verification Requirements'
      control_id: 5.3.8 OS Command Injection
      control_url: https://github.com/OWASP/ASVS/blob/master/4.0/en/0x13-V5-Validation-Sanitization-Encoding.md#v53-output-encoding-and-injection-prevention-requirements
      version: '4'
    references:
    - https://stackoverflow.com/questions/3172470/actual-meaning-of-shell-true-in-subprocess
    - https://docs.python.org/3/library/subprocess.html
    - https://docs.python.org/3/library/shlex.html
    - https://semgrep.dev/docs/cheat-sheets/python-command-injection/
    category: security
    technology:
    - python
    confidence: MEDIUM
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - vuln
    likelihood: MEDIUM
    impact: HIGH
  languages: [python]
  severity: ERROR