Individual skill
exploiting-server-side-includes-esi-injection
Exploiting Server-Side Includes (SSI) and Edge-Side Includes (ESI) injection where unsanitized input is reflected into content processed by an SSI-enabled web server or an ESI-capable cache/proxy (Squid, Varnish, Fastly, Akamai, nodesi), enabling command execution, file inclusion, SSRF, cookie theft (incl. HttpOnly), and XSS/WAF bypass. Activates when reflected input may be parsed as SSI/ESI directives.
internal/tools/skills/data/web-application-security/exploiting-server-side-includes-esi-injection/SKILL.md
Source commit d42f381ad34843e71a42658e5c57290c713e85af
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- Matches the observed repository HEAD
- Yes
- Scanner rules are current
- Yes
- Repository scan complete
- No
- Skill scan complete
- No
- Observed behavior
- Network or broad shell
- 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)
- 1,329
- Repository last updated
- Nov 9, 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
- esi-injection Declared skill tag
- ssi-injection Declared skill tag
- ssrf Declared skill tag
- owasp Declared skill tag
- web-security Declared skill tag
- writing Derived category
- security Derived category
- testing Derived category
- security-application Derived category
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# Exploiting SSI / ESI Injection
## When to Use
- During authorized tests where a server uses SSI (files `.shtml`, `.shtm`, `.stm`) or a cache/CDN supports ESI
- When reflected input may be parsed as directives before the page is served or cached
- When responses include `Surrogate-Control: content="ESI/1.0"` (server uses ESI) — but absence does NOT rule it out
- When a reverse proxy / CDN (Squid3, Varnish, Fastly, Akamai ETS, NodeJS esi/nodesi) sits in front of the app
- When you need to bypass HttpOnly cookie flags, XSS filters, or WAFs via include/var directives
## Critical: Variants Most Often Missed
ESI capabilities differ per software, so a failed payload on one stack does not mean immune. Probe both reflected and blind. SSI directive form: `<!--#directive param="value" -->`; ESI form: `<esi:...>`.
