Xslt Injection

This playbook walks you through exploiting XSLT injection when you control stylesheet input on a server-side transform. It starts with processor fingerprinting (Xalan, Saxon, libxslt, MSXML) then maps out the escalation paths: XXE via DTD entities, file reads through document(), EXSLT write primitives for arbitrary file creation, and platform-specific RCE surfaces in PHP (php:function with system calls), Java (Runtime.exec via extension namespaces), and .NET (msxsl:script blocks). The coverage is thorough and includes working payloads for each vector. Use this when you see parameters like stylesheet, transform, or template in XML processing endpoints. Most modern setups disable the nastiest features, so you'll often end up pivoting to document() SSRF or read-only XXE rather than full RCE, but the skill covers both scenarios.

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last updated: Aug 21, 2026

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Install

$ npx -y skills add yaklang/hack-skills --skill xslt-injection --agent claude-code

Installs into .claude/skills of the current project.

Files

SKILL: XSLT Injection — Testing Playbook

AI LOAD INSTRUCTION: XSLT injection occurs when attacker-influenced XSLT is compiled/executed server-side. Map the processor family first (Java/.NET/PHP/libxslt). Then chain document(), external entities, EXSLT, or embedded script/extension functions per platform. Authorized testing only; many payloads are destructive. Routing note: if input is generic XML parsing and may not flow through XSLT, cross-load xxe-xml-external-entity; if you care about outbound document(http:...) requests, cross-load ssrf-server-side-request-forgery.

0. QUICK START

Find sinks: parameters named xslt, stylesheet, transform, template, SOAP stylesheets, report generators, XML→HTML converters.
Probe reflection: inject unique namespace or xsl:value-of select="'marker'" — if output changes, execution likely.
Fingerprint processor (§1).
Escalate by family: document() / XXE (§2–3), EXSLT write (§4), PHP (§5), Java (§6), .NET (§7).