CVE-2024-45802
📋 TL;DR
This vulnerability in Squid proxy allows trusted servers to cause denial of service against all clients using the proxy through resource management flaws. It affects Squid installations where the proxy communicates with trusted upstream servers. The vulnerability stems from input validation issues and improper resource handling.
💻 Affected Systems
- Squid
📦 What is this software?
Squid by Squid Cache
⚠️ Risk & Real-World Impact
Worst Case
Complete proxy service disruption affecting all clients, potentially causing business-critical application failures and network connectivity issues.
Likely Case
Proxy service degradation or crashes requiring restart, impacting web access for all users behind the proxy.
If Mitigated
Limited impact with proper network segmentation and monitoring, but still requires patching to fully mitigate.
🎯 Exploit Status
Exploitation requires being a trusted server that can communicate with the Squid proxy. No public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.10
Vendor Advisory: https://github.com/squid-cache/squid/security/advisories/GHSA-f975-v7qw-q7hj
Restart Required: Yes
Instructions:
1. Backup current Squid configuration. 2. Upgrade Squid to version 6.10 or later using your package manager. 3. Verify the new version is running. 4. Restart Squid service to apply the fix.
🔧 Temporary Workarounds
Restrict trusted servers
allLimit which upstream servers Squid considers trusted to reduce attack surface
# Configure Squid ACLs to restrict trusted peers
# Edit squid.conf to limit cache_peer access
Resource limits
allImplement resource limits and monitoring to detect and mitigate DoS attempts
# Set connection limits in squid.conf
acl localnet src 10.0.0.0/8
http_access allow localnet
# Add connection limits
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Squid from untrusted upstream servers
- Deploy monitoring and alerting for unusual resource consumption or proxy crashes
🔍 How to Verify
Check if Vulnerable:
Check Squid version with 'squid -v' or 'squid --version'. If version is below 6.10, the system is vulnerable.Check Version:
squid -v || squid --versionVerify Fix Applied:
After upgrade, verify version is 6.10 or higher with 'squid -v'. Test proxy functionality with client requests.📡 Detection & Monitoring
Log Indicators:
- Unusual resource exhaustion messages
- Frequent proxy crashes or restarts
- Errors related to connection handling or resource management
Network Indicators:
- Increased connection failures from clients
- Unusual traffic patterns from trusted servers
- Proxy service unavailability
SIEM Query:
source="squid" AND ("fatal" OR "crash" OR "resource" OR "connection limit")