CVE-2022-35927 in Contiki-NG
Summary
by MITRE • 08/05/2022
Contiki-NG is an open-source, cross-platform operating system for IoT devices. In the RPL-Classic routing protocol implementation in the Contiki-NG operating system, an incoming DODAG Information Option (DIO) control message can contain a prefix information option with a length parameter. The value of the length parameter is not validated, however, and it is possible to cause a buffer overflow when copying the prefix in the set_ip_from_prefix function. This vulnerability affects anyone running a Contiki-NG version prior to 4.7 that can receive RPL DIO messages from external parties. To obtain a patched version, users should upgrade to Contiki-NG 4.7 or later. There are no workarounds for this issue.
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Analysis
by VulDB Data Team • 08/05/2022
The vulnerability CVE-2022-35927 represents a critical buffer overflow flaw within the Contiki-NG operating system's implementation of the RPL-Classic routing protocol. This issue specifically manifests in the set_ip_from_prefix function where incoming DODAG Information Options (DIO) control messages are processed. The vulnerability stems from insufficient validation of the prefix information option's length parameter, creating a scenario where malicious actors can manipulate this parameter to trigger unauthorized memory access patterns. As a distributed routing protocol designed for Internet of Things environments, RPL-Classic enables devices to form dynamic networks and establish optimal paths for data transmission, making this flaw particularly dangerous in networked IoT deployments where devices may receive untrusted control messages from external sources.
The technical exploitation of this vulnerability occurs when an attacker crafts a malformed DIO message containing a prefix information option with an invalid length parameter. When the Contiki-NG system processes this message through the set_ip_from_prefix function, the unchecked length parameter leads to a buffer overflow condition during the prefix copying operation. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and more specifically aligns with CWE-787, representing out-of-bounds write operations. The vulnerability's impact is amplified by the fact that Contiki-NG devices often operate in resource-constrained environments where memory corruption can lead to complete system compromise, including arbitrary code execution or denial of service conditions. The RPL-Classic protocol's design inherently requires devices to process and validate information from neighboring nodes, making the system susceptible to this particular attack vector.
The operational impact of CVE-2022-35927 extends beyond simple denial of service scenarios, as it creates potential for persistent system compromise within IoT networks. Devices running Contiki-NG versions prior to 4.7 that are configured to receive RPL DIO messages from external parties become vulnerable to remote exploitation, allowing attackers to potentially gain control over network routing decisions and compromise the integrity of the entire network topology. This vulnerability particularly affects smart city deployments, industrial IoT systems, and sensor networks where Contiki-NG is commonly deployed for low-power, wireless communication. The attack surface is broad given that many IoT devices in these environments are designed to automatically accept and process routing information from neighboring nodes without extensive validation, creating a persistent risk for network-wide compromise. Network administrators must consider that this vulnerability could be exploited to create routing loops, deny legitimate network access, or enable man-in-the-middle attacks within IoT infrastructure.
Mitigation strategies for CVE-2022-35927 require immediate deployment of Contiki-NG version 4.7 or later, which includes proper validation of the prefix information option length parameter. This upgrade addresses the root cause by implementing appropriate bounds checking within the set_ip_from_prefix function to prevent buffer overflow conditions when processing malformed DIO messages. Organizations should conduct comprehensive inventory assessments to identify all Contiki-NG devices within their IoT infrastructure that may be vulnerable to this attack vector. The vulnerability's characteristics align with ATT&CK technique T1059.007, which covers command and script injection, as the buffer overflow could potentially enable arbitrary code execution. Additionally, network segmentation and monitoring of RPL-Classic traffic can provide early detection of anomalous DIO message patterns that may indicate exploitation attempts. Security teams should implement regular vulnerability scanning procedures targeting IoT devices running Contiki-NG to identify and remediate similar issues before they can be exploited in production environments. Given the lack of workarounds for this specific vulnerability, proactive patch management and device firmware updates represent the only effective defensive measures against exploitation attempts.