CVE-2020-11898: Treck TCP/IP Information Disclosure Flaw

CVE-2020-11898 Overview

CVE-2020-11898 is a critical vulnerability in the Treck TCP/IP stack before version 6.0.1.66 that improperly handles an IPv4/ICMPv4 Length Parameter Inconsistency. This flaw allows remote attackers to trigger an information leak by sending specially crafted network packets that exploit the inconsistent handling of length parameters in the IPv4/ICMPv4 protocol implementation.

This vulnerability is part of the "Ripple20" collection of vulnerabilities discovered in the Treck TCP/IP stack, which is widely deployed across IoT devices, industrial control systems, medical devices, and enterprise equipment from numerous vendors including Cisco, HPE, Dell, and Aruba Networks.

Critical Impact

Remote attackers can exploit this vulnerability over the network without authentication to leak sensitive information from affected devices, potentially exposing memory contents that could facilitate further attacks.

Affected Products

• Treck TCP/IP stack versions prior to 6.0.1.66
• Devices from multiple vendors incorporating the vulnerable Treck TCP/IP stack (including Cisco, HPE, Dell, Aruba Networks, and NetApp products)
• IoT devices, industrial control systems, and medical equipment using the affected stack

Discovery Timeline

• June 17, 2020 - CVE-2020-11898 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-11898

Vulnerability Analysis

This vulnerability stems from improper buffer boundary checks (CWE-119) when processing IPv4/ICMPv4 packets. The Treck TCP/IP stack fails to properly validate the consistency between declared length parameters and actual packet data when handling ICMPv4 messages within IPv4 traffic. When a malformed packet containing inconsistent length values is received, the stack may read beyond intended memory boundaries, resulting in information disclosure.

The attack is network-accessible and requires no user interaction or authentication, making it particularly dangerous for internet-connected devices. Successful exploitation can lead to both information leakage (exposing sensitive data from device memory) and potential denial of service conditions.

Root Cause

The root cause of CVE-2020-11898 is inadequate validation of length parameters in the IPv4/ICMPv4 packet processing code within the Treck TCP/IP stack. The implementation fails to verify that the declared length values in packet headers are consistent with each other and with the actual packet size, leading to out-of-bounds memory access operations.

Attack Vector

An attacker can exploit this vulnerability by sending specially crafted IPv4 packets containing ICMPv4 messages with inconsistent length parameters to a target device running the vulnerable Treck TCP/IP stack. The attack is performed remotely over the network and does not require any form of authentication or user interaction.

The exploitation involves:

1. Crafting an IPv4 packet with an embedded ICMPv4 message
2. Setting inconsistent length values in the packet headers
3. Sending the malicious packet to the target device
4. The vulnerable stack processes the packet and reads beyond intended memory boundaries
5. Sensitive information from device memory may be leaked back to the attacker

For technical details on the vulnerability mechanism and exploitation, refer to the JSOF Ripple20 Overview and CERT Vulnerability Details.

Detection Methods for CVE-2020-11898

Indicators of Compromise

• Unusual ICMPv4 traffic patterns with malformed or inconsistent length parameters
• Network traffic containing IPv4 packets with mismatched header length fields
• Unexpected ICMP error responses or information disclosure from network devices
• Anomalous memory dumps or data in network traffic from embedded devices

Detection Strategies

• Deploy network intrusion detection systems (IDS) with signatures for Ripple20 vulnerabilities and malformed ICMPv4 packets
• Monitor network traffic for IPv4/ICMPv4 packets with inconsistent length parameters using deep packet inspection
• Implement anomaly detection for unusual ICMP traffic patterns targeting embedded devices and IoT infrastructure
• Use asset inventory tools to identify devices running vulnerable Treck TCP/IP stack versions

Monitoring Recommendations

• Enable detailed logging on network perimeter devices for ICMPv4 traffic analysis
• Monitor for unexpected data exfiltration patterns from IoT and embedded devices
• Implement network segmentation monitoring to detect lateral movement following potential exploitation
• Review vendor security advisories from Cisco, HPE, Dell, and NetApp for affected product lists

How to Mitigate CVE-2020-11898

Immediate Actions Required

• Identify all devices in your environment using the Treck TCP/IP stack and determine their firmware versions
• Apply vendor-provided patches for affected devices immediately where available
• Implement network segmentation to isolate vulnerable IoT and embedded devices from critical infrastructure
• Disable or block unnecessary ICMPv4 traffic at network perimeters where operationally feasible
• Monitor for exploitation attempts using network intrusion detection systems

Patch Information

Treck has released version 6.0.1.66 and later of their TCP/IP stack that addresses this vulnerability. Organizations should contact their device vendors for firmware updates that incorporate the patched Treck stack. Multiple vendors have released security advisories and patches:

• CERT Vulnerability Advisory VU#257161 provides a comprehensive list of affected vendors
• Aruba Networks Security Alert
• Cisco Security Advisory
• HPE Security Document
• NetApp Security Advisory

Workarounds

• Implement strict network segmentation to isolate devices running vulnerable Treck TCP/IP stack versions
• Deploy firewall rules to block or rate-limit ICMPv4 traffic to vulnerable devices from untrusted networks
• Use VPNs or other secure tunneling mechanisms to protect vulnerable devices that must remain connected
• Consider temporary device isolation until patches can be applied, especially for internet-facing systems

# Example: Block potentially malicious ICMP traffic to vulnerable devices using iptables
# Apply to network boundaries protecting vulnerable IoT/embedded devices

# Rate limit ICMP to prevent exploitation attempts
iptables -A INPUT -p icmp --icmp-type any -m limit --limit 10/second --limit-burst 20 -j ACCEPT
iptables -A INPUT -p icmp --icmp-type any -j DROP

# Block ICMP from external networks to vulnerable internal devices (adjust subnets as needed)
iptables -A FORWARD -p icmp -s 0.0.0.0/0 -d 10.0.0.0/8 -j DROP