CVE-2023-2156 in Linux
Summary
by MITRE • 05/10/2023
A flaw was found in the networking subsystem of the Linux kernel within the handling of the RPL protocol. This issue results from the lack of proper handling of user-supplied data, which can lead to an assertion failure. This may allow an unauthenticated remote attacker to create a denial of service condition on the system.
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Analysis
by VulDB Data Team • 05/28/2023
The vulnerability identified as CVE-2023-2156 represents a critical flaw within the Linux kernel's networking subsystem that specifically impacts the RPL (Routing Protocol for Low-Power and Lossy Networks) implementation. This protocol is designed for use in IoT and embedded systems where devices operate with limited power and network reliability. The vulnerability stems from insufficient validation of user-supplied data during the processing of RPL messages, creating a potential pathway for malicious actors to exploit the system's assertion mechanisms. The flaw manifests when the kernel fails to properly sanitize incoming network packets that conform to the RPL protocol specifications, leading to unexpected behavior that can be leveraged for system disruption.
The technical implementation of this vulnerability resides in the kernel's network stack where RPL protocol handling routines do not adequately validate packet contents before processing them. When malformed or specially crafted RPL packets are received, the kernel's assertion checks fail, causing the system to terminate the network processing thread or potentially trigger a kernel panic. This assertion failure represents a classic example of improper input validation that can be exploited through the principle of least privilege violations, where an attacker can manipulate system behavior through network communication without requiring authentication. The vulnerability operates at the kernel level, making it particularly dangerous as it can affect the entire system's network functionality and potentially lead to complete system unresponsiveness.
The operational impact of CVE-2023-2156 extends beyond simple denial of service conditions, as it can compromise the availability of network services on affected systems. In embedded environments where RPL is commonly deployed, such as smart grid infrastructure, industrial control systems, or sensor networks, this vulnerability can result in cascading failures that affect critical operations. The remote nature of the attack means that adversaries can exploit this flaw from outside the network perimeter, making it particularly concerning for systems that lack proper network segmentation or intrusion detection mechanisms. From a cybersecurity perspective, this vulnerability aligns with attack patterns described in the ATT&CK framework under the T1499.004 technique for network denial of service, and represents a weakness in the kernel's defensive posture against malformed network traffic.
Systems most vulnerable to this flaw include those running Linux kernels with RPL protocol support, particularly embedded devices, IoT appliances, and network infrastructure equipment that rely on low-power wireless networking standards. The exploitability of this vulnerability is enhanced in environments where network monitoring is insufficient, as attackers can craft packets that trigger the assertion failure without requiring any special privileges or authentication credentials. Security professionals should consider implementing network segmentation, rate limiting, and packet filtering rules to mitigate exposure while awaiting official kernel patches. The vulnerability also highlights the importance of proper kernel module validation and input sanitization practices, as outlined in the CWE database under categories related to improper input validation and assertion failure conditions. Organizations should prioritize patch management procedures to address this vulnerability promptly, as the lack of authentication requirements makes it particularly attractive to threat actors seeking to disrupt network services.