CVE-2020-13987 in Contiki
Summary
by MITRE • 12/12/2020
An issue was discovered in Contiki through 3.0. An Out-of-Bounds Read vulnerability exists in the uIP TCP/IP Stack component when calculating the checksums for IP packets in upper_layer_chksum in net/ipv4/uip.c.
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Analysis
by VulDB Data Team • 12/16/2020
The vulnerability CVE-2020-13987 represents a critical out-of-bounds read flaw within the Contiki operating system version 3.0 and earlier, specifically affecting the uIP TCP/IP stack implementation. This issue resides in the net/ipv4/uip.c file where the upper_layer_chksum function handles checksum calculations for IP packets. The flaw occurs during the processing of network traffic where the system attempts to read memory locations beyond the allocated buffer boundaries, creating a potential vector for malicious exploitation. Such vulnerabilities in embedded networking stacks can have severe implications for device security and network integrity.
The technical nature of this vulnerability stems from improper bounds checking during checksum calculation operations within the IPv4 networking layer. When the uIP stack processes incoming packets, the upper_layer_chksum function fails to validate array indices or buffer limits before accessing memory locations. This allows an attacker to craft specially malformed IP packets that trigger the out-of-bounds read condition, potentially leading to information disclosure, system instability, or even arbitrary code execution depending on the specific implementation details and memory layout. The vulnerability manifests as a classic buffer overflow pattern where the system reads beyond allocated memory regions, violating fundamental memory safety principles.
The operational impact of CVE-2020-13987 extends beyond simple memory corruption, as it affects the core networking functionality of Contiki-based devices. In embedded environments where Contiki is commonly deployed for IoT applications, sensor networks, and constrained devices, this vulnerability can compromise network reliability and security. Attackers could exploit this weakness to gain unauthorized access to device memory, potentially extracting sensitive information or causing denial of service conditions that disrupt network operations. The vulnerability affects devices that rely on the uIP stack for IPv4 communication, making it particularly concerning for networked embedded systems where security is paramount.
Mitigation strategies for this vulnerability involve immediate patching of Contiki versions prior to 3.0, ensuring all affected systems receive the latest security updates from the Contiki development team. Organizations should also implement network monitoring to detect anomalous packet patterns that might indicate exploitation attempts. Additionally, defensive programming techniques such as bounds checking, memory sanitization, and input validation should be enforced throughout the networking stack implementation. The vulnerability aligns with CWE-129, which addresses improper bounds checking in input validation scenarios, and could potentially map to ATT&CK technique T1059 for remote code execution through network-based attacks. System administrators should also consider implementing network segmentation and access controls to limit the potential impact of exploitation attempts on critical infrastructure components.