CVE-2015-8575 in Linux
Summary
by MITRE
The sco_sock_bind function in net/bluetooth/sco.c in the Linux kernel before 4.3.4 does not verify an address length, which allows local users to obtain sensitive information from kernel memory and bypass the KASLR protection mechanism via a crafted application.
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Analysis
by VulDB Data Team • 07/07/2022
The vulnerability identified as CVE-2015-8575 resides within the Linux kernel's Bluetooth subsystem, specifically in the sco_sock_bind function located in net/bluetooth/sco.c. This flaw represents a critical security issue that affects Linux kernel versions prior to 4.3.4, enabling local attackers to exploit a missing input validation mechanism that could lead to information disclosure and bypass of kernel security protections. The vulnerability stems from insufficient address length verification during Bluetooth socket binding operations, creating a pathway for malicious applications to access kernel memory regions that should remain protected from user-space access.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where an application accesses memory beyond its allocated bounds. In this case, the sco_sock_bind function fails to validate the address length parameter provided by user-space applications, allowing attackers to craft specially designed socket binding requests that cause the kernel to read memory locations beyond the intended buffer boundaries. This improper validation creates a classic information disclosure vulnerability where sensitive kernel memory contents, including addresses and other confidential data, can be leaked to unprivileged user processes. The flaw specifically impacts the kernel's KASLR (Kernel Address Space Layout Randomization) protection mechanism, which is designed to randomize kernel memory layout to prevent exploitation of memory corruption vulnerabilities.
The operational impact of CVE-2015-8575 extends beyond simple information disclosure, as it fundamentally undermines the security model of the Linux kernel's memory protection mechanisms. When local users can bypass KASLR, they effectively gain significant intelligence about the kernel's memory layout, which significantly reduces the effectiveness of modern exploit mitigation techniques. Attackers can leverage this information to craft more sophisticated exploits that would otherwise be impossible to develop without knowledge of kernel memory addresses. The vulnerability operates through a direct memory access pattern that does not require elevated privileges, making it particularly dangerous as it can be exploited by any local user with basic system access. This represents a violation of the principle of least privilege and demonstrates how seemingly minor input validation flaws can create substantial security implications.
Mitigation strategies for CVE-2015-8575 primarily focus on upgrading to kernel versions 4.3.4 or later, where the address length validation has been properly implemented. System administrators should prioritize patching affected systems, particularly those running older kernel versions that may be exposed to local privilege escalation attacks. Additionally, organizations should implement monitoring for suspicious socket binding activities and consider deploying kernel lockdown mechanisms that restrict user-space access to kernel memory interfaces. The vulnerability's classification under ATT&CK technique T1068, which covers local privilege escalation, highlights the need for comprehensive system hardening measures including mandatory access controls and privilege separation. Network administrators should also consider implementing process monitoring to detect anomalous behavior patterns that might indicate exploitation attempts, while security teams should maintain updated threat intelligence regarding potential exploitation of this vulnerability in the wild.