CVE-2024-29195: 
CBL Mariner vulnerability analysis and mitigation

The azure-c-shared-utility, a C library for AMQP/MQTT communication to Azure Cloud Services used by the Azure IoT C SDK, was found to contain a critical vulnerability (CVE-2024-29195) that could lead to remote code execution. The vulnerability was discovered in early 2024 and involves integer wraparound, under-allocation, and heap buffer overflow issues due to vulnerabilities in the parameter checking mechanism (GitHub Advisory).

The vulnerability exists in the buffer length parameter validation of the Azure C SDK. When processing AMQP/MQTT communications, the library fails to properly validate input parameters, which can result in integer wraparound conditions and heap buffer overflows. The vulnerability has been assigned a CVSS v3.1 base score of 6.0 (Medium) with the vector string CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:L, indicating that while the attack requires high complexity and privileges, it can potentially lead to high impact on confidentiality and integrity (NVD).

If successfully exploited, this vulnerability could allow an attacker to execute arbitrary code remotely on affected systems. The impact is particularly severe for IoT devices communicating with Azure IoT Hub, as it could lead to complete system compromise. However, successful exploitation requires specific conditions including a compromised Azure account, the ability to bypass the IoT hub service max message payload limit of 128KB, and the capability to overwrite code space with remote code (GitHub Advisory).

Exploitation of this vulnerability requires several specific conditions to be met: 1) The attacker must have access to a compromised Azure account that allows sending malformed payloads to the device via IoT Hub service, 2) The ability to bypass the IoT hub service maximum message payload limit of 128KB, and 3) The capability to overwrite code space with remote code. These requirements make the vulnerability challenging to exploit but still pose a significant risk in environments where these conditions can be met (GitHub Advisory).

The vulnerability has been patched in commit 1129147c38ac02ad974c4c701a1e01b2141b9fe2. Users are strongly advised to update to the latest version of the azure-c-shared-utility library that includes this fix. The patch implements proper malloc size checks to prevent integer wraparound and buffer overflow conditions (Azure Commit).