mcp-server-semgrep/semgrep-rules/ruby/rails/security/audit/xss/templates/dangerous-link-to.yaml

MCP Server for Semgrep Integration - static code analysis with AI

rules:
- id: dangerous-link-to
  message: >-
    Detected a template variable used in 'link_to'. This will
    generate dynamic data in the 'href' attribute.
    This allows a malicious actor to
    input the 'javascript:' URI and is subject to cross-
    site scripting (XSS) attacks. If using a relative URL,
    start with a literal forward slash and concatenate the URL,
    like this: 'link_to "Here", "/"+@link'. You may also consider
    setting the Content Security Policy (CSP) header.
  metadata:
    source-rule-url: https://github.com/presidentbeef/brakeman/blob/main/lib/brakeman/checks/check_link_to.rb
    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://cheatsheetseries.owasp.org/cheatsheets/Ruby_on_Rails_Cheat_Sheet.html#cross-site-scripting-xss
    - https://brakemanscanner.org/docs/warning_types/link_to_href/
    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: <%= ... %>
  - pattern-not-inside: link_to ... "/" + ... @$VAR
  - pattern-not-inside: link_to ... '/' + ... @$VAR
  - pattern: link_to ... @$VAR