mcp-server-semgrep/semgrep-rules/csharp/lang/security/open-redirect.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: open-redirect
  mode: taint
  pattern-sources:
  - patterns:
    - focus-metavariable: $PARAM
    - pattern-inside: |
        public $TYPE $FUNCNAME (..., string $PARAM, ...) {
          ...
        }
  pattern-sinks:
  - patterns:
    - pattern: Redirect(...)
    - pattern-not-inside: |
        if (IsLocalUrl(...)) { 
            ... 
            Redirect(...); 
            ...
        }
    - pattern-not-inside: |
        if ($URL.IsLocalUrl(...)) { 
            ... 
            Redirect(...); 
            ...
        }
  message: >-
    A query string parameter may contain a URL value that could cause the
    web application to redirect the request to a malicious website controlled by
    an attacker. Make sure to sanitize this parameter sufficiently.
  metadata:
    category: security
    technology:
    - csharp
    cwe:
    - "CWE-601: URL Redirection to Untrusted Site ('Open Redirect')"
    references:
    - https://cwe.mitre.org/data/definitions/601.html
    owasp:
    - A01:2021 - Broken Access Control
    subcategory:
    - vuln
    likelihood: MEDIUM
    impact: MEDIUM
    confidence: LOW
  languages:
  - csharp
  severity: ERROR