CVE-2011-1079 in Linux
Summary
by MITRE
The bnep_sock_ioctl function in net/bluetooth/bnep/sock.c in the Linux kernel before 2.6.39 does not ensure that a certain device field ends with a \0 character, which allows local users to obtain potentially sensitive information from kernel stack memory, or cause a denial of service (BUG and system crash), via a BNEPCONNADD command.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2011-1079 resides within the Linux kernel's Bluetooth implementation, specifically in the bnep_sock_ioctl function located in net/bluetooth/bnep/sock.c. This flaw affects kernel versions prior to 2.6.39 and represents a classic case of improper input validation that can lead to information disclosure and system stability issues. The vulnerability manifests when processing the BNEPCONNADD command, which is used to establish Bluetooth Network Encapsulation Protocol connections. The root cause lies in the function's failure to properly null-terminate a device field, creating a potential security exposure that can be exploited by local attackers.
The technical nature of this vulnerability stems from a buffer management issue where the bnep_sock_ioctl function does not guarantee that a device field will be properly terminated with a null character. This oversight creates a situation where memory following the device field in kernel space may contain uninitialized data or remnants of previous operations. When the system processes the BNEPCONNADD command, this improperly handled device field can cause the kernel to read beyond its allocated boundaries, potentially exposing sensitive kernel stack memory contents to local users. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a specific manifestation of improper boundary checking in kernel-level code.
From an operational perspective, this vulnerability presents multiple attack vectors and consequences for system security and stability. Local attackers can exploit the information disclosure aspect to potentially extract sensitive kernel memory contents, which may include cryptographic keys, passwords, or other confidential data that could be used to escalate privileges or conduct further attacks. The denial of service component creates a risk of system crashes and BUG messages, potentially leading to complete system instability and requiring manual intervention to restore normal operations. The impact is particularly concerning given that this vulnerability exists in kernel space where local users already have elevated privileges and can directly manipulate kernel data structures.
The exploitation of this vulnerability requires local access to the system, as it involves kernel-level operations that are not directly accessible from network-based attacks. However, the implications extend beyond simple privilege escalation, as the information disclosure could provide attackers with insights into kernel memory layout and system internals. Security practitioners should note that this vulnerability demonstrates the critical importance of proper memory management in kernel code, particularly when handling user-supplied data. The flaw also relates to ATT&CK technique T1068, which involves the exploitation of local privilege escalation opportunities, and T1566, which covers the use of valid accounts to access systems. Organizations should prioritize patching affected systems and implementing proper kernel memory validation checks to prevent similar vulnerabilities from being exploited in the future.
This vulnerability highlights the necessity of comprehensive code review processes for kernel-level implementations, particularly focusing on input validation and memory boundary management. The fix implemented in kernel version 2.6.39 addresses the specific issue by ensuring proper null termination of device fields, thereby preventing the reading of uninitialized kernel memory. System administrators should ensure that all Linux systems running kernel versions prior to 2.6.39 are updated to prevent exploitation of this vulnerability, which could lead to both information disclosure and system stability issues. The vulnerability serves as a reminder of the critical security implications that can arise from seemingly minor implementation oversights in kernel code, emphasizing the need for rigorous testing and validation of security-critical system components.