CVE-2019-17518 in Dialog Semiconductor
Summary
by MITRE
The Bluetooth Low Energy implementation on Dialog Semiconductor SDK through 1.0.14.1081 for DA1468x devices responds to link layer packets with a payload length larger than expected, allowing attackers in radio range to cause a buffer overflow via a crafted packet. This affects, for example, August Smart Lock.
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Analysis
by VulDB Data Team • 03/29/2024
The vulnerability identified as CVE-2019-17518 represents a critical buffer overflow flaw within the Bluetooth Low Energy stack implementation of Dialog Semiconductor's DA1468x device SDK versions up to 1.0.14.1081. This issue specifically targets the link layer packet processing mechanism where the system fails to properly validate payload lengths before processing incoming data. The flaw exists in the protocol handling layer of the Bluetooth implementation, creating a scenario where malformed packets can trigger memory corruption. The vulnerability affects numerous consumer IoT devices including the August Smart Lock, which relies on this Bluetooth stack for secure communication and access control functionality. The impact extends beyond simple device malfunction as it creates potential entry points for remote attackers within radio range of affected devices.
The technical exploitation of this vulnerability occurs through the manipulation of Bluetooth Low Energy link layer packets that contain payloads exceeding the expected size limits. When the DA1468x device processes such packets, the insufficient bounds checking in the packet handling routine leads to memory buffer overflow conditions. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write operations. The implementation flaw specifically affects the Bluetooth Low Energy controller's ability to handle variable length packets, where the system assumes all incoming packets conform to predefined size constraints without proper validation. Attackers can craft malicious packets with oversized payloads that cause the device's memory management system to write beyond allocated buffer boundaries, potentially leading to arbitrary code execution or system crashes.
From an operational perspective, this vulnerability creates significant security risks for IoT deployments where August Smart Lock and similar devices are used for physical access control. The remote nature of the attack means that adversaries within radio range can potentially compromise device functionality without physical access, which undermines the security model of these access control systems. The buffer overflow condition can result in device instability, denial of service attacks, or more severe exploitation scenarios where attackers might gain unauthorized access to the device's operational environment. The vulnerability is particularly concerning in commercial and residential settings where these locks are deployed, as it could enable unauthorized individuals to gain access to secured premises. The affected devices may also exhibit unpredictable behavior, making them unreliable for critical security applications and potentially leading to cascading failures in connected security ecosystems.
Mitigation strategies for CVE-2019-17518 should prioritize firmware updates from Dialog Semiconductor and device manufacturers, particularly for affected August Smart Lock models and other DA1468x-based products. Organizations should implement network segmentation to limit the exposure of these devices to untrusted networks and consider disabling Bluetooth functionality when not actively required. The implementation of proper input validation mechanisms and bounds checking should be enforced in all Bluetooth stack implementations to prevent similar vulnerabilities. Security monitoring should include detection of anomalous Bluetooth packet patterns that might indicate exploitation attempts, and device hardening measures should be implemented to limit the impact of potential buffer overflow conditions. This vulnerability highlights the importance of secure coding practices in embedded systems and the necessity of thorough security testing for IoT device implementations, particularly in environments where physical security is paramount. The flaw demonstrates the critical need for proper memory management and input validation in resource-constrained IoT devices, aligning with ATT&CK technique T1059.007 for command and scripting interpreter usage and T1203 for exploitation for privilege escalation.