Individual skill
testing-for-email-header-injection
Tests web application email functionality (contact forms, password reset, newsletter subscriptions) for CRLF/SMTP header injection using Burp Suite and OWASP ZAP, checking whether attackers can inject headers, modify recipients, or abuse forms for spam relay. Use when testing any user-input-driven email-sending feature during a penetration test.
skills/testing-for-email-header-injection/SKILL.md
Source commit 54a798831d2266a3ca61ce68a7acb80b81160d57
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- Observed behavior
- Network or broad shell
- Last checked
- Nov 9, 2026
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- Repository stars (not skill ratings)
- 35,926
- Repository last updated
- Aug 31, 2026
- License
- Apache-2.0
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- ai-agents Repository topic
- claude-code Repository topic
- cybersecurity Repository topic
- incident-response Repository topic
- mitre-attack Repository topic
- penetration-testing Repository topic
- red-team Repository topic
- security Repository topic
- cloud-security Repository topic
- malware-analysis Repository topic
- email-injection Declared skill tag
- smtp-injection Declared skill tag
- crlf-injection Declared skill tag
- header-injection Declared skill tag
- spam-relay Declared skill tag
- contact-form Declared skill tag
- email-security Declared skill tag
- testing Derived category
- marketing Derived category
- security Derived category
- security-application Derived category
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Read excerpt
# Testing for Email Header Injection
## When to Use
- When testing contact forms, feedback forms, or "email a friend" functionality
- During assessment of password reset email functionality
- When testing newsletter subscription or notification email systems
- During penetration testing of applications that send emails based on user input
- When auditing email-related API endpoints for header injection
## Prerequisites
- Burp Suite for intercepting and modifying HTTP requests
- Understanding of SMTP protocol and email header structure
- Knowledge of CRLF injection techniques (\r\n sequences)
- Test email accounts for receiving injected emails