CVE-2023-25950
📋 TL;DR
This HTTP request smuggling vulnerability in HAProxy allows attackers to manipulate legitimate user requests by exploiting improper request/response handling. Attackers can potentially steal sensitive information or cause denial-of-service conditions. Only HAProxy versions 2.6.1-2.6.7 and 2.7.0 are affected.
💻 Affected Systems
- HAProxy
📦 What is this software?
Haproxy by Haproxy
Haproxy by Haproxy
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept and modify legitimate user requests to steal authentication tokens, session cookies, or sensitive data, potentially leading to account takeover or data breaches.
Likely Case
Attackers could poison cache responses, perform session hijacking, or cause service disruption through malformed requests that confuse backend servers.
If Mitigated
With proper patching and network segmentation, impact is limited to potential temporary service disruption without data compromise.
🎯 Exploit Status
HTTP request smuggling vulnerabilities are commonly exploited in the wild, though no specific exploit code for this CVE has been publicly released.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6.8, 2.7.1, or later versions
Vendor Advisory: https://www.haproxy.org/
Restart Required: Yes
Instructions:
1. Download latest patched version from haproxy.org 2. Replace vulnerable binary 3. Restart HAProxy service 4. Verify version with 'haproxy -v'
🔧 Temporary Workarounds
Request validation at backend
allImplement strict HTTP request validation at backend servers to reject malformed requests
Depends on backend application - implement HTTP request validation logic
🧯 If You Can't Patch
- Implement WAF with HTTP request smuggling protection rules
- Use network segmentation to isolate HAProxy from sensitive backend systems
🔍 How to Verify
Check if Vulnerable:
Run 'haproxy -v' and check if version is 2.6.1-2.6.7 or 2.7.0Check Version:
haproxy -vVerify Fix Applied:
Verify version is 2.6.8, 2.7.1 or later with 'haproxy -v'📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP request patterns
- Malformed request headers
- Backend server errors for valid requests
Network Indicators:
- HTTP requests with conflicting Content-Length and Transfer-Encoding headers
- Abnormal request/response timing
SIEM Query:
source="haproxy.log" AND ("malformed" OR "invalid" OR "error") AND http_request🔗 References
- https://git.haproxy.org/?p=haproxy-2.7.git%3Ba=commit%3Bh=3ca4223c5e1f18a19dc93b0b09ffdbd295554d46
- https://jvn.jp/en/jp/JVN38170084/
- https://www.haproxy.org/
- https://git.haproxy.org/?p=haproxy-2.7.git%3Ba=commit%3Bh=3ca4223c5e1f18a19dc93b0b09ffdbd295554d46
- https://jvn.jp/en/jp/JVN38170084/
- https://www.haproxy.org/
