CVE-2023-46852
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code or cause denial of service via a buffer overflow in Memcached proxy mode. Attackers can exploit this by sending specially crafted multiget requests with excessive spaces after the 'get' substring. Organizations running Memcached in proxy mode are affected.
💻 Affected Systems
- Memcached
📦 What is this software?
Memcached by Memcached
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or lateral movement within the network.
Likely Case
Denial of service causing Memcached service crashes and application downtime.
If Mitigated
Limited impact if proper network segmentation and access controls prevent external exploitation.
🎯 Exploit Status
Exploitation requires sending malformed multiget requests, which is straightforward for attackers with network access to vulnerable instances.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.6.22
Vendor Advisory: https://github.com/memcached/memcached/commit/76a6c363c18cfe7b6a1524ae64202ac9db330767
Restart Required: Yes
Instructions:
1. Download Memcached 1.6.22 or later from official sources. 2. Stop the Memcached service. 3. Install the updated version. 4. Restart the Memcached service.
🔧 Temporary Workarounds
Disable Proxy Mode
allDisable Memcached proxy mode if not required for your deployment.
Edit Memcached configuration to remove proxy mode settings
Restart Memcached service
Network Access Controls
linuxRestrict network access to Memcached instances using firewall rules.
iptables -A INPUT -p tcp --dport 11211 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 11211 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Memcached instances from untrusted networks.
- Deploy intrusion detection systems to monitor for suspicious multiget request patterns.
🔍 How to Verify
Check if Vulnerable:
Check if Memcached version is below 1.6.22 and proxy mode is enabled in configuration.Check Version:
memcached -h | grep versionVerify Fix Applied:
Confirm Memcached version is 1.6.22 or higher and test with multiget requests containing spaces.📡 Detection & Monitoring
Log Indicators:
- Memcached crash logs
- Error messages related to buffer overflow or segmentation faults
Network Indicators:
- Unusual multiget requests with excessive spaces
- Traffic spikes to Memcached port 11211
SIEM Query:
source="memcached.log" AND ("segmentation fault" OR "buffer overflow" OR "get" followed by multiple spaces)