mcp-server-semgrep/semgrep-rules/go/lang/security/audit/xss/no-direct-write-to-responsewriter.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: no-direct-write-to-responsewriter
  languages:
  - go
  message: >-
    Detected directly writing or similar in 'http.ResponseWriter.write()'.
    This bypasses HTML escaping that prevents cross-site scripting
    vulnerabilities. Instead, use the 'html/template' package
    and render data using 'template.Execute()'.
  metadata:
    category: security
    cwe:
    - "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"
    owasp:
    - A07:2017 - Cross-Site Scripting (XSS)
    - A03:2021 - Injection
    references:
    - https://blogtitle.github.io/robn-go-security-pearls-cross-site-scripting-xss/
    technology:
    - go
    confidence: LOW
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
  patterns:
  - pattern-either:
    - pattern-inside: |
        func $HANDLER(..., $WRITER http.ResponseWriter, ...) {
          ...
        }
    - pattern-inside: |
        func $HANDLER(..., $WRITER *http.ResponseWriter, ...) {
          ...
        }
    - pattern-inside: |
        func(..., $WRITER http.ResponseWriter, ...) {
          ...
        }
  - pattern-either:
    - pattern: $WRITER.Write(...)
    - pattern: (*$WRITER).Write(...)
  - pattern-not: $WRITER.Write([]byte("..."))
  severity: WARNING