mcp-server-semgrep/semgrep-rules/ruby/rails/security/audit/xss/templates/unquoted-attribute.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: unquoted-attribute
  message: 'Detected a unquoted template variable as an attribute. If unquoted, a malicious actor could
    inject custom JavaScript handlers. To fix this, add quotes around the template expression, like this:
    "<%= expr %>".'
  metadata:
    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://brakemanpro.com/2017/09/08/cross-site-scripting-in-rails#unquoted-attributes
    - https://flask.palletsprojects.com/en/1.1.x/security/#cross-site-scripting-xss
    category: security
    technology:
    - rails
    cwe2022-top25: true
    cwe2021-top25: true
    subcategory:
    - audit
    likelihood: LOW
    impact: MEDIUM
    confidence: LOW
  languages:
  - generic
  paths:
    include:
    - '*.erb'
  severity: WARNING
  patterns:
  - pattern-inside: <$TAG ...>
  - pattern-not-inside: ="..."
  - pattern-not-inside: ="<%= ... %>"
  - pattern-not-inside: ='...'
  - pattern-not-inside: ='<%= ... %>'
  - pattern: <%= ... %>
  fix-regex:
    regex: <%=(.*?)%>
    replacement: '"<%=\1%>"'