CVE-2016-9918 in BlueZ
Summary
by MITRE
In BlueZ 5.42, an out-of-bounds read was identified in "packet_hexdump" function in "monitor/packet.c" source file. This issue can be triggered by processing a corrupted dump file and will result in btmon crash.
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Analysis
by VulDB Data Team • 08/24/2019
The vulnerability identified as CVE-2016-9918 represents a critical out-of-bounds read condition within the BlueZ Bluetooth stack version 5.42. This flaw exists within the packet_hexdump function located in the monitor/packet.c source file, specifically affecting the btmon utility which is used for monitoring Bluetooth traffic. The issue demonstrates a classic buffer overread vulnerability that occurs when processing malformed or corrupted Bluetooth packet dump files. Such vulnerabilities are particularly dangerous in network monitoring tools as they can lead to arbitrary code execution or system crashes when the tool encounters unexpected data formats during analysis.
The technical implementation of this vulnerability stems from inadequate input validation within the packet_hexdump function which fails to properly bounds-check array accesses when parsing Bluetooth packet data. When btmon encounters a corrupted dump file containing malformed packet data, the function attempts to read memory locations beyond the allocated buffer boundaries, resulting in undefined behavior and ultimately a crash of the monitoring utility. This type of vulnerability falls under CWE-125, which specifically addresses out-of-bounds read conditions in software systems. The flaw represents a fundamental failure in memory management and input sanitization that allows attackers to manipulate the program flow through carefully crafted input data.
From an operational perspective, this vulnerability poses significant risks to Bluetooth network monitoring capabilities and can be exploited to disrupt critical infrastructure operations. The btmon utility is commonly used by system administrators and security professionals for debugging and analyzing Bluetooth communications, making this crash vulnerability particularly concerning for environments where continuous monitoring is required. Attackers could potentially leverage this weakness to perform denial-of-service attacks against Bluetooth monitoring systems, effectively preventing legitimate network analysis and troubleshooting activities. The vulnerability also aligns with ATT&CK technique T1059.007, which covers the use of command and scripting interpreter for system compromise, as the crash could be used to disrupt system operations and potentially serve as a precursor to more sophisticated attacks.
Mitigation strategies for CVE-2016-9918 should prioritize immediate patching of BlueZ installations to version 5.43 or later, which contains the necessary fixes for the out-of-bounds read condition. Organizations should also implement strict input validation measures for any Bluetooth packet data processing pipelines and consider deploying network segmentation to limit the impact of potential exploitation. Additionally, monitoring systems should be configured with proper error handling and crash recovery mechanisms to prevent complete service disruption. The vulnerability highlights the importance of input validation in network monitoring tools and demonstrates why security patches for core system components must be applied promptly to prevent exploitation of memory corruption vulnerabilities that can lead to system instability and potential privilege escalation opportunities.