CVE-2019-15134 in RIOT
Summary
by MITRE
RIOT through 2019.07 contains a memory leak in the TCP implementation (gnrc_tcp), allowing an attacker to consume all memory available for network packets and thus effectively stopping all network threads from working. This is related to _receive in sys/net/gnrc/transport_layer/tcp/gnrc_tcp_eventloop.c upon receiving an ACK before a SYN.
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Analysis
by VulDB Data Team • 11/26/2023
The vulnerability identified as CVE-2019-15134 represents a critical memory management flaw within the RIOT operating system's TCP implementation known as gnrc_tcp. This issue affects all versions of RIOT up to and including the 2019.07 release, fundamentally compromising the system's ability to maintain network connectivity and operational stability. The vulnerability specifically targets the network stack's handling of TCP packet processing, creating a condition where memory resources become progressively consumed until the system reaches a state of complete network paralysis.
The technical root cause of this memory leak resides in the _receive function located within the file sys/net/gnrc/transport_layer/tcp/gnrc_tcp_eventloop.c. This flaw manifests when the TCP implementation receives an ACK packet before receiving the corresponding SYN packet, which violates the standard TCP handshake sequence. The improper handling of this out-of-order packet delivery causes the system to allocate memory for packet processing without proper cleanup mechanisms, resulting in gradual memory consumption that ultimately exhausts available resources. This condition demonstrates a classic memory leak pattern where allocated memory is not properly deallocated, creating a resource exhaustion scenario that affects the entire network subsystem.
The operational impact of this vulnerability extends beyond simple resource consumption, as it effectively renders the entire network functionality of affected RIOT systems unusable. When the memory pool dedicated to network packet processing becomes exhausted, all network threads cease to operate properly, preventing any further network communication. This creates a denial-of-service condition that can be exploited by attackers to disrupt network services, potentially leading to complete system incapacitation in networked embedded devices. The vulnerability is particularly concerning in IoT and embedded systems where memory resources are typically limited and network connectivity is essential for system operation.
From a cybersecurity perspective, this vulnerability aligns with CWE-401, which describes improper handling of memory allocation and deallocation, and represents a significant weakness in the system's resource management capabilities. The attack vector is relatively straightforward as it requires only the ability to send malformed TCP packets to the target system, making it accessible to attackers with basic network capabilities. The vulnerability also maps to ATT&CK technique T1499.001, which involves network disruption through resource exhaustion attacks, highlighting the potential for this flaw to be leveraged in broader cyber operations targeting IoT and embedded systems infrastructure.
Mitigation strategies for CVE-2019-15134 should prioritize immediate patching of affected RIOT versions to the latest releases that contain the corrected TCP implementation. Organizations should implement network monitoring solutions to detect unusual memory consumption patterns that may indicate exploitation attempts. Additionally, deploying network segmentation and access controls can limit the potential impact of successful attacks, while regular system updates and vulnerability assessments should be conducted to prevent similar issues from occurring in other components of the embedded system infrastructure.