CVE-2016-9801 in BlueZ
Summary
by MITRE
In BlueZ 5.42, a buffer overflow was observed in "set_ext_ctrl" function in "tools/parser/l2cap.c" source file when processing corrupted dump file.
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Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2016-9801 represents a critical buffer overflow condition within the BlueZ Bluetooth protocol stack version 5.42. This flaw manifests specifically within the set_ext_ctrl function located in the tools/parser/l2cap.c source file, where the software fails to properly validate input data when processing corrupted dump files. The issue arises from insufficient bounds checking mechanisms that allow maliciously crafted input to exceed allocated memory buffers, potentially leading to arbitrary code execution or system instability. This vulnerability directly impacts the Bluetooth networking infrastructure and affects systems that utilize BlueZ as their primary Bluetooth stack implementation.
The technical implementation of this vulnerability stems from improper memory management practices within the Bluetooth packet parsing functionality. When the set_ext_ctrl function processes external dump files containing malformed data structures, it attempts to copy input data into fixed-size buffers without adequate validation of the input length. This classic buffer overflow scenario occurs because the function assumes that input data will conform to expected formats and sizes, failing to account for corrupted or maliciously constructed input files that may contain oversized data sequences. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow, where insufficient bounds checking allows data to overwrite adjacent memory locations. The flaw specifically targets the parsing logic used for analyzing Bluetooth Low Energy (BLE) and classic Bluetooth traffic captures, making it particularly dangerous in environments where network traffic analysis tools process untrusted input data.
The operational impact of CVE-2016-9801 extends beyond simple system crashes or denial of service conditions, as it creates potential entry points for remote attackers to execute arbitrary code on affected systems. Systems utilizing BlueZ 5.42 that process Bluetooth dump files from untrusted sources become vulnerable to exploitation, particularly in environments where security tools analyze network traffic or where automated systems process captured Bluetooth data. The vulnerability affects a wide range of devices including smartphones, laptops, embedded systems, and network infrastructure components that rely on BlueZ for Bluetooth functionality. Attackers could potentially craft malicious dump files that, when processed by vulnerable BlueZ implementations, would trigger the buffer overflow condition and allow for privilege escalation or complete system compromise. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1203 for Exploitation for Client Execution, as it enables attackers to execute malicious code through compromised Bluetooth processing functionality.
Mitigation strategies for CVE-2016-9801 focus primarily on immediate software updates and input validation improvements. Organizations should prioritize upgrading to BlueZ versions that contain patches addressing this specific buffer overflow condition, typically found in versions subsequent to 5.42. The fix involves implementing proper bounds checking mechanisms within the set_ext_ctrl function to validate input data length before copying to allocated buffers. Additionally, system administrators should implement strict input validation policies for any Bluetooth traffic analysis tools that process external dump files, ensuring that all input undergoes thorough sanitization and length verification before processing. Network segmentation and access controls should be strengthened to limit exposure of vulnerable systems to untrusted Bluetooth traffic sources. Security monitoring should be enhanced to detect anomalous behavior indicative of buffer overflow exploitation attempts, including unusual memory access patterns or unexpected system crashes during Bluetooth processing operations. The vulnerability demonstrates the critical importance of input validation in network protocol implementations and highlights the need for robust memory safety practices in embedded systems and network infrastructure components.