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How the CVE Works
The vulnerability (CWE-611) in the Math library (v0.2.0) stems from improper XML external entity (XXE) restriction. The `loadXML` function in the `MathML` class uses the `LIBXML_DTDLOAD` flag, enabling external entity references. An attacker crafts a malicious XML file embedding entities that reference local files (e.g., /etc/passwd). When processed, the library fetches and exfiltrates file contents via base64-encoded HTTP requests. The exploit requires parsing a MathML file, leveraging PHP’s `libxml` extension without proper entity filtering.
DailyCVE Form
Platform: Math Library
Version: 0.2.0
Vulnerability: XXE (CWE-611)
Severity: Critical
Date: 2023-XX-XX
Prediction: Patch expected Q2 2024
What Undercode Say:
Exploitation Commands
1. Payload Creation (poc.xml):
<!DOCTYPE x [<!ENTITY % ext SYSTEM "file:///etc/passwd"> %ext;]>
2. Listener Setup:
nc -lvnp 9999
3. Trigger Exploit:
php math.php
Mitigation Code
Disable external entities in PHP:
libxml_disable_entity_loader(true);
Or use a custom entity loader:
set_external_entity_loader(function() { return null; });
Detection Script
grep -r "LIBXML_DTDLOAD" /path/to/math/library/
Analytics
- Attack Vector: Network (HTTP/XML)
- Exploit Complexity: Low
- Affected Systems: PHP 8.1+ with MathML parsing
- Patch Priority: Immediate (critical data exposure)
Post-Exploit Cleanup
rm -f poc.xml math.php
References
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
