Treck TCP/IP Stack IPv6 Out-of-bounds Read Vulnerability (CVE-2020-11899, Ripple20)
Executive & SecOps Summary
SECOPS ASSESSMENTIoT, medical devices, industrial control systems, and network equipment utilizing Treck TCP/IP embedded protocol stack versions prior to 6.0.1.66
An adjacent attacker can send specially crafted IPv6 packets to trigger an out-of-bounds read, leading to information disclosure or system crash/denial of service (DoS)
Apply the latest firmware updates provided by your device vendors (incorporating Treck 6.0.1.66 or higher) and restrict unnecessary IPv6 traffic at the network boundary
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Because Treck is an embedded stack, direct source patching is typically managed via hardware vendor firmware updates. For automated environments, use the vendor-specific CLI to upgrade the firmware image:
# Example: Upgrading firmware on a Cisco/compatible network switch via CLI
copy tftp://10.1.1.50/cisco-ios-patched-image.bin flash:
boot system flash:cisco-ios-patched-image.bin
write memory
reload2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict IPv6 traffic at the network perimeter or disable IPv6 on affected segments where it is not required.
# Block external IPv6 traffic using iptables/ip6tables
ip6tables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
ip6tables -A INPUT -i lo -j ACCEPT
# Drop all other incoming IPv6 traffic except link-local
ip6tables -A INPUT -s fe80::/10 -j ACCEPT
ip6tables -A INPUT -j DROP3. Log Audit & IoC Verification Commands
Analyze network traffic captures (PCAP) to detect anomalous IPv6 extension headers or malformed packets targeting the embedded devices.
# Use tshark to inspect IPv6 extension headers for potential anomalies
tshark -r network_traffic.pcap -Y 'ipv6.nxt == 0 or ipv6.nxt == 60' -T fields -e ipv6.src -e ipv6.dstStop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
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Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2020-11899) is an Out-of-bounds Read (CWE-125) vulnerability in the IPv6 packet processing module of the Treck TCP/IP protocol stack, widely used in embedded systems. The root cause lies in insufficient validation of length fields within IPv6 headers or extension headers, allowing the parser to read memory beyond the allocated buffer boundary.
2. Exploitation Mechanics & Attack Scenario
An attacker situated on the same local network segment (L2/L3 adjacent) can transmit specially crafted IPv6 packets to the target device. By specifying an option header length that exceeds the actual payload size, the attacker forces the Treck stack parser to read adjacent memory spaces. This can result in a system crash (Kernel Panic/BSOD) causing a Denial of Service, or potentially leak sensitive data residing in the adjacent memory.
3. Infrastructure & Business Impact
As part of the 'Ripple20' vulnerability suite, this flaw affects a vast array of global vendors including Cisco, HP, Dell, and Aruba. In OT/ICS environments where high availability is critical (e.g., smart grids, medical devices, industrial gateways), unexpected device reboots can severely disrupt business continuity. Its inclusion in the CISA KEV list highlights that this vulnerability is actively targeted and poses an immediate threat.
Official Vendor Advisories & References
The Treck TCP/IP stack before 6.0.1.66 has an IPv6 Out-of-bounds Read.
Frequently Asked SecOps Questions (CVE-2020-11899)
FAQQ1. How critical is CVE-2020-11899 and is it actively exploited in the wild?
CVE-2020-11899 is rated CVSS 5.4 (MEDIUM) with a 30-day EPSS exploitation probability of 18.4%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2020-11899?
Primary impacted vendors include treck across tcp_ip_stack. Scope summary: Treck TCP/IP Stack versions prior to 6.0.1.66 (including various OEM vendor implementations)
Q3. What temporary mitigations or workarounds exist for CVE-2020-11899 before patching?
[Mitigation] Apply the latest firmware updates provided by your device vendors (incorporating Treck 6.0.1.66 or higher) and restrict unnecessary IPv6 traffic at the network boundary Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2020-11899
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