Individual skill
analyzing-email-headers-for-phishing-investigation
Parse and analyze email headers to trace the origin of phishing emails, verify sender authenticity, and identify spoofing through SPF, DKIM, and DMARC validation.
internal/tools/skills/data/digital-forensics/analyzing-email-headers-for-phishing-investigation/SKILL.md
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- Last checked
- Nov 7, 2026
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- Repository last updated
- Nov 7, 2026
- License
- Apache-2.0
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- cybersecurity Repository topic
- security Repository topic
- bug-bounty Repository topic
- automation Repository topic
- autonomous-pentesting Repository topic
- ai-agent Repository topic
- ai-security Repository topic
- ethical-hacking Repository topic
- golang Repository topic
- penetration-testing Repository topic
- forensics Declared skill tag
- email-analysis Declared skill tag
- phishing Declared skill tag
- spf Declared skill tag
- dkim Declared skill tag
- dmarc Declared skill tag
- header-analysis Declared skill tag
- engineering Derived category
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# Analyzing Email Headers for Phishing Investigation
## When to Use
- When investigating a suspected phishing email to determine its true origin
- For verifying sender authenticity and detecting email spoofing
- During incident response when a user has clicked a phishing link
- When tracing the delivery path and relay servers of a suspicious email
- For validating SPF, DKIM, and DMARC alignment to identify forgery
## Detection Gaps & Validation
- **Most-missed header evidence:** analysts read `From`/`Received` and stop. Also parse `Authentication-Results`/`ARC-Authentication-Results` (the receiver's own verdict, harder to forge than `Received-SPF`), `Return-Path` vs `From` (envelope mismatch), the `Message-ID` domain vs the sender domain, and `X-Originating-IP`. Everything below your own perimeter MTA in the `Received` chain is attacker-controlled and forgeable - trust only hops you operate.
- **SPF/DKIM "pass" is not "legitimate":** a pass only proves the message left authorized infrastructure - fully consistent with a compromised mailbox, a shared ESP (SendGrid/Mailchimp) abused by another tenant, or a lookalike domain with its own valid records. Verify DKIM with the `d=`/`s=` selector via `dig TXT s._domainkey.d` and check alignment, not just the pass flag.
- **Cross-corroborate the finding:** validate the sending IP against the SPF record AND reverse DNS AND reputation (AbuseIPDB/VirusTotal); confirm a phishing URL against URLhaus/PhishTank; hash attachments and check VT - do not call "spoofed" on a header mismatch alone.