CVE-2021-43082
📋 TL;DR
This CVE describes a classic buffer overflow vulnerability in Apache Traffic Server's stats-over-http plugin that allows attackers to overwrite memory. Attackers could potentially execute arbitrary code or crash the server. This affects Apache Traffic Server version 9.1.0.
💻 Affected Systems
- Apache Traffic Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or installation of persistent backdoors.
Likely Case
Denial of service through server crashes or memory corruption, potentially leading to service disruption.
If Mitigated
Limited impact if proper network segmentation and least privilege principles are implemented.
🎯 Exploit Status
Buffer overflow vulnerabilities in HTTP plugins typically have low exploitation complexity, though no public exploit code has been confirmed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 9.1.1 or later
Vendor Advisory: https://lists.apache.org/thread/k01797hyncx53659wr3o72s5cvkc3164
Restart Required: Yes
Instructions:
1. Download Apache Traffic Server 9.1.1 or later from the official Apache website. 2. Stop the Traffic Server service. 3. Install the updated version following the official installation guide. 4. Restart the Traffic Server service.
🔧 Temporary Workarounds
Disable stats-over-http plugin
allTemporarily disable the vulnerable plugin until patching can be completed.
Edit records.config and set CONFIG proxy.config.http.enable_stats_over_http INT 0
traffic_ctl config reload
🧯 If You Can't Patch
- Implement strict network access controls to limit access to the stats-over-http endpoint to trusted IP addresses only.
- Deploy web application firewall (WAF) rules to detect and block buffer overflow attempts targeting the stats endpoint.
🔍 How to Verify
Check if Vulnerable:
Check the Traffic Server version with 'traffic_server -V' and verify if it's 9.1.0. Also check if stats-over-http is enabled in records.config.Check Version:
traffic_server -VVerify Fix Applied:
After patching, verify the version is 9.1.1 or later with 'traffic_server -V' and test the stats-over-http endpoint functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual requests to /_stats endpoint
- Server crashes or segmentation faults in error logs
- Memory corruption warnings
Network Indicators:
- Excessive or malformed HTTP requests to the stats endpoint
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="traffic_server" AND (uri_path="/_stats" OR error="segmentation fault" OR error="buffer overflow")