CVE-2025-53538
📋 TL;DR
A memory handling vulnerability in Suricata's HTTP/2 parser allows uncontrolled memory consumption when processing data on stream 0. This can lead to denial of service through resource exhaustion, causing loss of network visibility. Affects Suricata installations with HTTP/2 parsing enabled.
💻 Affected Systems
- Suricata
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service through memory exhaustion, causing Suricata to crash and lose all network intrusion detection/prevention capabilities.
Likely Case
Gradual memory consumption leading to performance degradation and eventual service disruption, resulting in partial or complete loss of monitoring visibility.
If Mitigated
Minimal impact with proper monitoring and resource limits in place, though some performance degradation may still occur.
🎯 Exploit Status
Exploitation requires sending specially crafted HTTP/2 traffic to the monitored network.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.0.11 or 8.0.0
Vendor Advisory: https://github.com/OISF/suricata/security/advisories/GHSA-qrr7-crgj-cmh3
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Update Suricata to version 7.0.11 or 8.0.0 using your package manager. 3. Restart Suricata service. 4. Verify the new version is running.
🔧 Temporary Workarounds
Disable HTTP/2 Parser
allCompletely disable HTTP/2 parsing to prevent exploitation
Edit suricata.yaml and set 'http2-enabled: no' under app-layer protocol configuration
Signature-based Blocking
allUse Suricata signature to drop HTTP/2 traffic on stream 0
Add to local.rules: drop http2 any any -> any any (frame:http2.hdr; byte_test:1,=,0,3; byte_test:4,=,0,5; sid: 1;)
🧯 If You Can't Patch
- Implement the signature-based workaround to block malicious HTTP/2 traffic
- Monitor system memory usage closely and implement resource limits on Suricata process
🔍 How to Verify
Check if Vulnerable:
Check Suricata version with 'suricata --build-info' and verify if it's in affected range (7.0.10 or below, or 8.0.0-beta1 through rc1)Check Version:
suricata --build-info | grep 'Version:'Verify Fix Applied:
Verify version is 7.0.11 or 8.0.0+ with 'suricata --build-info'📡 Detection & Monitoring
Log Indicators:
- Unusual memory consumption patterns in Suricata logs
- Process crashes or restarts
- High memory usage alerts
Network Indicators:
- HTTP/2 traffic with stream ID 0
- Unusual HTTP/2 frame patterns
SIEM Query:
source="suricata" ("memory" OR "resource" OR "crash") AND ("http2" OR "stream 0")