CVE-2020-11901
📋 TL;DR
CVE-2020-11901 is a critical remote code execution vulnerability in the Treck TCP/IP stack that allows attackers to execute arbitrary code by sending a single malformed DNS response. This affects millions of embedded IoT devices, networking equipment, and industrial control systems from numerous vendors. The vulnerability is part of the Ripple20 disclosure affecting hundreds of millions of devices worldwide.
💻 Affected Systems
- Dell Edge Gateways
- HP Aruba networking equipment
- Cisco industrial devices
- Schneider Electric PLCs
- Rockwell Automation controllers
- Numerous other embedded/IoT devices
📦 What is this software?
Tcp\/ip by Treck
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to gain persistent remote access, pivot to internal networks, deploy ransomware, or cause physical damage in industrial environments.
Likely Case
Remote code execution leading to data theft, network reconnaissance, lateral movement, and deployment of malware or botnets.
If Mitigated
Limited impact with proper network segmentation, but still poses risk to vulnerable devices in isolated segments.
🎯 Exploit Status
Exploitation requires DNS traffic to reach vulnerable device. Attack can be triggered via DNS responses from malicious or compromised DNS servers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Treck TCP/IP stack 6.0.1.66 or later
Vendor Advisory: https://www.jsof-tech.com/ripple20/
Restart Required: Yes
Instructions:
1. Identify affected devices using vendor advisories. 2. Contact device vendors for firmware updates. 3. Apply vendor-provided patches. 4. Reboot devices after patching. 5. Verify patch application.
🔧 Temporary Workarounds
DNS Filtering
linuxBlock or filter DNS traffic to vulnerable devices from untrusted sources
iptables -A INPUT -p udp --dport 53 -j DROP
iptables -A INPUT -p tcp --dport 53 -j DROP
Network Segmentation
allIsolate vulnerable devices in separate VLANs with strict firewall rules
🧯 If You Can't Patch
- Segment vulnerable devices in isolated network zones with strict egress/ingress filtering
- Implement DNS sinkholing or use trusted internal DNS servers only
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against vendor advisories. Use asset discovery tools to identify Treck stack devices.Check Version:
Device-specific - consult vendor documentation for version checking commandsVerify Fix Applied:
Verify firmware version is patched (6.0.1.66+). Test with vendor-provided verification tools if available.📡 Detection & Monitoring
Log Indicators:
- DNS query failures
- Unexpected process crashes
- Memory corruption errors in system logs
Network Indicators:
- Malformed DNS packets
- DNS responses with crafted payloads
- Unexpected outbound connections from embedded devices
SIEM Query:
source="dns" AND (packet_size>512 OR malformed_packet=true) AND dest_ip IN [vulnerable_device_ips]🔗 References
- http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-006.txt
- https://jsof-tech.com/vulnerability-disclosure-policy/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-treck-ip-stack-JyBQ5GyC
- https://www.dell.com/support/article/de-de/sln321836/dell-response-to-the-ripple20-vulnerabilities
- https://www.jsof-tech.com/ripple20/
- https://www.kb.cert.org/vuls/id/257161
- https://www.kb.cert.org/vuls/id/257161/
- https://www.treck.com
- http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2020-006.txt
- https://jsof-tech.com/vulnerability-disclosure-policy/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-treck-ip-stack-JyBQ5GyC
- https://www.dell.com/support/article/de-de/sln321836/dell-response-to-the-ripple20-vulnerabilities
- https://www.jsof-tech.com/ripple20/
- https://www.kb.cert.org/vuls/id/257161
- https://www.kb.cert.org/vuls/id/257161/
- https://www.treck.com
