Individual skill
exploiting-reverse-tab-nabbing
Identifying and exploiting reverse tabnabbing, where a link opened with target="_blank" without rel="noopener" gives the newly opened (attacker-controlled) page a reference to the originating window via window.opener, allowing it to redirect the original tab to a phishing clone. Activates when assessing user-controllable links, outbound links, or any anchor/window.open that opens new tabs.
internal/tools/skills/data/web-application-security/exploiting-reverse-tab-nabbing/SKILL.md
Source commit d42f381ad34843e71a42658e5c57290c713e85af
What was checked
- Matches the observed repository HEAD
- Yes
- Scanner rules are current
- Yes
- Repository scan complete
- No
- Skill scan complete
- No
- Observed behavior
- Instructions only
- Last checked
- Nov 9, 2026
These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.
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Repository context
- Repository stars (not skill ratings)
- 1,320
- Repository last updated
- Nov 8, 2026
- License
- Apache-2.0
Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.
- 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
- penetration-testing Declared skill tag
- reverse-tabnabbing Declared skill tag
- phishing Declared skill tag
- owasp Declared skill tag
- web-security Declared skill tag
- security Derived category
- testing Derived category
- security-application Derived category
Files and excerpt
File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.
Read excerpt
# Exploiting Reverse Tab Nabbing
## When to Use
- During authorized assessments where users can control the `href` of links rendered to other users
- When the app renders outbound/user-supplied links with `target="_blank"` (profile URLs, comments, posts, support tickets)
- When testing "open in new tab" behaviors, share links, or SSO/OAuth pop-ups
- When reviewing markdown/rich-text renderers that auto-link URLs without `rel="noopener"`
- When evaluating phishing resistance of flows that send users to external sites
## Prerequisites
- **Authorization**: Engagement scope covering client-side/phishing-style findings
- **Attacker-controlled page**: A page that uses `window.opener` to redirect the original tab