mcp-server-semgrep/semgrep-rules/javascript/node-expat/security/audit/expat-xxe.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: expat-xxe
  message: >-
    If unverified user data can reach the XML Parser it can result in XML External or
    Internal Entity (XXE) Processing vulnerabilities
  metadata:
    owasp:
    - A04:2017 - XML External Entities (XXE)
    - A05:2021 - Security Misconfiguration
    cwe:
    - 'CWE-611: Improper Restriction of XML External Entity Reference'
    category: security
    technology:
    - node-expat
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
    references:
    - https://owasp.org/Top10/A05_2021-Security_Misconfiguration
  languages:
  - javascript
  - typescript
  severity: WARNING
  patterns:
  - pattern-either:
    - pattern: |
        var $EXPAT = require('node-expat');
        ...
        new $EXPAT.Parser(...);
        ...
        $PARSER.parse(...);
    - pattern: |
        var $EXPAT = require('node-expat');
        ...
        new $EXPAT.Parser(...);
        ...
        $PARSER.write(...);
    - pattern: |
        require('node-expat');
        ...
        new Parser(...);
        ...
        $PARSER.parse(...);
    - pattern: |
        require('node-expat');
        ...
        new Parser(...);
        ...
        $PARSER.write(...);
  - pattern-not: |
      var $EXPAT = require('node-expat');
      ...
      new $EXPAT.Parser(...);
      ...
      $PARSER.parse("...");
  - pattern-not: |
      var $EXPAT = require('node-expat');
      ...
      new $EXPAT.Parser(...);
      ...
      $PARSER.write("...");
  - pattern-not: |
      require('node-expat');
      ...
      new Parser(...);
      ...
      $PARSER.parse("...");
  - pattern-not: |
      require('node-expat');
      ...
      new Parser(...);
      ...
      $PARSER.write("...");
  - pattern-not: |
      $X = "...";
      ...
      $PARSER.parse($X);
  - pattern-not: |-
      $X = "...";
      ...
      $PARSER.write($X);