CVE-2016-9803 in BlueZ
Summary
by MITRE
In BlueZ 5.42, an out-of-bounds read was observed in "le_meta_ev_dump" function in "tools/parser/hci.c" source file. This issue exists because 'subevent' (which is used to read correct element from 'ev_le_meta_str' array) is overflowed.
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Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2016-9803 represents a critical out-of-bounds read condition within the BlueZ Bluetooth protocol stack version 5.42. This issue occurs in the hci.c source file within the tools/parser directory, specifically within the le_meta_ev_dump function that processes LE (Low Energy) meta events. The flaw arises from improper bounds checking when handling subevent parameters, creating a scenario where an attacker can manipulate the subevent value to access memory locations beyond the allocated ev_le_meta_str array boundaries.
This vulnerability falls under the CWE-129 category of Improper Validation of Array Index, specifically manifesting as an out-of-bounds read that can lead to information disclosure or potential system instability. The issue stems from the function's failure to validate the subevent parameter against the actual size of the ev_le_meta_str array, allowing arbitrary memory access patterns. When an attacker crafts a malformed LE meta event with an oversized subevent value, the system attempts to read from memory locations that may contain sensitive data or system information, potentially exposing confidential information to unauthorized parties.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can be exploited to gain insights into the system's memory layout and potentially enable more sophisticated attacks. An attacker with the ability to send malicious Bluetooth packets to a vulnerable BlueZ implementation could trigger this condition, causing the application to read beyond its allocated memory space. This behavior can lead to denial of service conditions where the application crashes or becomes unstable, or worse, could potentially allow for information leakage that might aid in further exploitation attempts.
From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, as it represents a foundational weakness that could enable attackers to gather system information before launching more targeted attacks. The vulnerability affects any system running BlueZ 5.42 or earlier versions where Bluetooth LE connections are processed, making it particularly concerning for IoT devices, mobile devices, and any system that relies on Bluetooth communication protocols. The attack surface is broad since Bluetooth LE is widely used across various platforms and device types, from smartphones and laptops to embedded systems and industrial equipment.
Mitigation strategies should focus on immediate patching of the BlueZ stack to version 5.43 or later, which contains the necessary fixes for this out-of-bounds read condition. System administrators should also implement network segmentation and Bluetooth access controls to limit exposure, while monitoring for anomalous Bluetooth traffic patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing proper input validation mechanisms at the application level and regularly update their Bluetooth protocol implementations to address similar vulnerabilities that may exist in other components of their Bluetooth infrastructure.