CVE-2020-4766
📋 TL;DR
This vulnerability in IBM MQ Internet Pass-Thru allows remote attackers to cause a denial of service by sending specially crafted MQ data requests that consume all available system resources. It affects IBM MQ Internet Pass-Thru versions 2.1 and 9.2. Organizations using these versions with internet-facing MQ services are particularly at risk.
💻 Affected Systems
- IBM MQ Internet Pass-Thru
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of IBM MQ Internet Pass-Thru, potentially affecting dependent applications and business processes that rely on MQ messaging.
Likely Case
Degraded performance or temporary unavailability of MQ services requiring service restart and cleanup of consumed resources.
If Mitigated
Minimal impact with proper network segmentation, rate limiting, and monitoring in place to detect and block malicious traffic patterns.
🎯 Exploit Status
The vulnerability requires sending malformed MQ data requests but does not require authentication, making exploitation straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply fixes from IBM APAR IT35138
Vendor Advisory: https://www.ibm.com/support/pages/node/6406254
Restart Required: Yes
Instructions:
1. Review IBM advisory IT35138. 2. Download and apply the appropriate fix for your version. 3. Restart IBM MQ Internet Pass-Thru services. 4. Verify the fix is applied correctly.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to IBM MQ Internet Pass-Thru to only trusted sources using firewalls or network ACLs.
Rate Limiting
allImplement rate limiting on MQ data requests to prevent resource exhaustion attacks.
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to trusted IP addresses only.
- Deploy monitoring and alerting for unusual resource consumption patterns on MQ servers.
🔍 How to Verify
Check if Vulnerable:
Check IBM MQ Internet Pass-Thru version using 'dspmqver' command and verify if running version 2.1 or 9.2.Check Version:
dspmqverVerify Fix Applied:
Verify APAR IT35138 is applied by checking fix status in IBM MQ administration console or via 'dspmqver' showing patched version.📡 Detection & Monitoring
Log Indicators:
- Unusual increase in MQ data request errors
- Resource exhaustion warnings in system logs
- High CPU/memory usage alerts
Network Indicators:
- Unusual volume of MQ data requests from single sources
- Malformed MQ protocol traffic patterns
SIEM Query:
source="mq_logs" AND (error_count > threshold OR resource_usage > 90%)