CVE-2019-8359 in Contiki
Summary
by MITRE
An issue was discovered in Contiki-NG through 4.2 and Contiki through 3.0. An out of bounds write is present in the data section during 6LoWPAN fragment re-assembly in the face of forged fragment offsets in os/net/ipv6/sicslowpan.c.
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Analysis
by VulDB Data Team • 06/02/2024
The vulnerability identified as CVE-2019-8359 represents a critical out-of-bounds write condition affecting Contiki-NG versions through 4.2 and Contiki versions through 3.0. This flaw resides within the 6LoWPAN fragment re-assembly mechanism, specifically in the os/net/ipv6/sicslowpan.c file where the system processes network packets with forged fragment offsets. The issue manifests when the network stack encounters malformed packet fragments that contain invalid offset values, leading to memory corruption during the re-assembly process. This vulnerability is particularly concerning in constrained network environments where Contiki operating systems are commonly deployed, such as IoT devices and wireless sensor networks that rely on 6LoWPAN protocols for IPv6 communication.
The technical implementation of this vulnerability stems from insufficient validation of fragment offset values during the 6LoWPAN re-assembly process. When the system receives packet fragments with invalid or maliciously crafted offset information, it fails to properly bounds-check the destination memory locations before writing fragment data. This allows an attacker to manipulate the re-assembly logic to write data beyond the allocated buffer boundaries, potentially overwriting adjacent memory regions including critical system variables, function pointers, or other network stack components. The flaw aligns with CWE-787, which specifically addresses out-of-bounds write vulnerabilities, and represents a classic example of memory safety issues in embedded systems where buffer management is critical due to limited resources and constrained execution environments.
The operational impact of CVE-2019-8359 extends beyond simple memory corruption, as it can enable various attack vectors including remote code execution, denial of service, and potential system compromise. In IoT deployments where Contiki systems are prevalent, this vulnerability could allow adversaries to disrupt network communications, gain unauthorized access to device resources, or cause persistent service degradation across entire sensor networks. The attack surface is particularly broad given that 6LoWPAN fragment re-assembly occurs frequently in wireless networks where packet fragmentation is common due to link layer constraints and varying network conditions. Network administrators and device manufacturers face significant challenges in mitigating this issue, as it affects core networking functionality and requires careful patching of the underlying network stack without disrupting existing network operations.
Mitigation strategies for CVE-2019-8359 should focus on implementing robust input validation and bounds checking within the 6LoWPAN fragment re-assembly code. The most effective approach involves updating to patched versions of Contiki-NG 4.3 or Contiki 3.1, which contain proper offset validation mechanisms and memory boundary checks. Organizations should also consider implementing network monitoring solutions to detect anomalous fragment offset patterns that may indicate exploitation attempts. Additionally, network segmentation and access controls can help limit the potential impact of successful attacks by isolating affected devices and preventing lateral movement within compromised networks. The vulnerability demonstrates the importance of memory safety practices in embedded systems and aligns with ATT&CK technique T1059, which covers the use of remote code execution capabilities, making it a critical concern for cybersecurity professionals managing IoT infrastructure and wireless sensor networks.