Testing For Email Header Injection

Testing For Email Header Injection

Overview

Cybersecurity skill for testing for email header injection. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "testing for email header injection"

• "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"

• 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

When NOT to Use

• When you lack proper authorization for testing
• For production systems without change management
• When the task requires legal or compliance expertise beyond technical scope

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
• Access to application features that trigger email sending
• SMTP server logs access for monitoring injection attempts

Workflow

# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Reconnaissance — Gather information about the target related to . Identify attack surface.
2. Vulnerability Identification — Enumerate potential weaknesses using automated and manual techniques.
3. Exploit Development/Selection — Use email header injection to identify and test vulnerabilities.
4. Execution — Execute the test in a controlled manner with proper authorization.
5. Post-Exploitation — Document the impact and extent of successful exploitation.
6. Reporting — Write detailed findings with reproduction steps, impact assessment, and remediation guidance.

Tools

• email header injection — Primary tool for this skill
• Vulnerability Scanner — Automated weakness identification
• Exploitation Framework — Controlled exploitation testing
• Reporting Tool — Findings documentation and tracking

Process

1. Design — Define interface, identify patterns, plan implementation
2. Implement — Write code following existing conventions, add tests
3. Verify — Run tests, check integration, validate behavior

Verification

• All procedures executed completely and documented
• Findings validated against multiple data sources
• False positives identified and filtered
• Results documented with evidence and timestamps
• Recommendations provided with risk-based prioritization

Anti-Rationalization Table