CVE-2020-11908

Vulnerability

CVE-2020-11908 is a vulnerability in the Treck TCP/IP stack, affecting versions before 4.7.1.27, where the DHCP component improperly handles '\0' (null) termination [1]. This memory management flaw is part of the Ripple20 collection and may be triggered when the stack processes a specially crafted DHCP packet. The vulnerability exists regardless of the specific build or runtime options used, as it stems from a core parsing error in the DHCP module [2].

Exploitation

An attacker can exploit this vulnerability over the network by sending a single, specially crafted DHCP packet to a device running the vulnerable Treck IP stack [1]. No authentication is required, and the attacker does not need any prior access to the targeted system. The attack is purely remote and does not require user interaction [2]. The malformed packet causes the stack to mishandle memory due to the null termination issue, potentially leading to memory corruption that an attacker could leverage for further exploitation.

Impact

Successful exploitation can lead to a denial of service, information disclosure, or remote code execution with the privileges of the affected Treck stack process [1][2]. The exact impact depends on the specific build and runtime options of the embedded system, but the attacker gains the ability to fully compromise the device's network stack. Given the widespread use of Treck IP stacks in industrial control systems and medical devices, the vulnerability poses a significant risk to these sectors [1].

Mitigation

The Treck IP stack should be updated to version 6.0.1.67 or later, as the fix for CVE-2020-11908 is included in that release [1]. Users of embedded systems that incorporate the Treck stack should contact their vendor for an updated firmware. Dell and Cisco have both provided advisories for affected products [3][4]. Until patches are applied, network traffic filtering and deep packet inspection can help block malformed DHCP packets [1]. There is no evidence that this CVE is listed in CISA's Known Exploited Vulnerabilities catalog.