CVE-2020-4581
📋 TL;DR
CVE-2020-4581 is a denial-of-service vulnerability in IBM DataPower Gateway where a remote attacker can crash the service by sending a specially crafted chunked transfer-encoding HTTP/2 request. This affects IBM DataPower Gateway versions 2018.4.1.0 through 2018.4.1.12. Organizations using these vulnerable versions with HTTP/2 enabled are at risk.
💻 Affected Systems
- IBM DataPower Gateway
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of the DataPower Gateway, disrupting all traffic routing and processing functions, potentially affecting downstream applications and services.
Likely Case
Service disruption requiring manual restart of the DataPower Gateway instance, causing temporary downtime for applications relying on the gateway.
If Mitigated
Minimal impact if HTTP/2 is disabled or if the gateway is behind a load balancer that can absorb the attack and failover to healthy instances.
🎯 Exploit Status
The vulnerability requires sending a specific HTTP/2 request pattern but does not require authentication or special privileges.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: IBM DataPower Gateway 2018.4.1.13 and later
Vendor Advisory: https://www.ibm.com/support/pages/node/6334707
Restart Required: Yes
Instructions:
1. Download the fix from IBM Fix Central. 2. Apply the fix using the DataPower WebGUI or CLI. 3. Restart the DataPower Gateway service.
🔧 Temporary Workarounds
Disable HTTP/2
allDisable HTTP/2 protocol support to prevent exploitation while maintaining HTTP/1.1 functionality.
Configure via DataPower WebGUI: Administration > Network > HTTP/2 Settings > Disable
🧯 If You Can't Patch
- Implement network filtering to block or rate-limit HTTP/2 requests at the perimeter.
- Deploy DataPower Gateway behind a WAF or load balancer configured to detect and block malicious HTTP/2 patterns.
🔍 How to Verify
Check if Vulnerable:
Check the DataPower Gateway version via CLI: 'show version' and verify if it's between 2018.4.1.0 and 2018.4.1.12.Check Version:
show versionVerify Fix Applied:
After patching, verify the version is 2018.4.1.13 or later using 'show version' and test with HTTP/2 requests to ensure stability.📡 Detection & Monitoring
Log Indicators:
- Log entries showing service crashes or restarts
- HTTP/2 request patterns with chunked transfer-encoding causing errors
Network Indicators:
- Unusual volume of HTTP/2 requests to DataPower endpoints
- Patterns of chunked transfer-encoding requests followed by service unavailability
SIEM Query:
source="datapower" AND ("HTTP/2" OR "chunked") AND ("crash" OR "restart" OR "error")