CVE-2014-7825 in Linux
Summary
by MITRE • 01/25/2023
kernel/trace/trace_syscalls.c in the Linux kernel through 3.17.2 does not properly handle private syscall numbers during use of the perf subsystem, which allows local users to cause a denial of service (out-of-bounds read and OOPS) or bypass the ASLR protection mechanism via a crafted application.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2014-7825 resides within the Linux kernel's trace_syscalls.c file and affects kernel versions through 3.17.2. This issue manifests when the perf subsystem interacts with private syscall numbers, creating a critical flaw that enables local attackers to exploit the system in multiple ways. The vulnerability specifically targets the kernel's handling of syscall tracing mechanisms, which are designed to monitor and record system calls for performance analysis and debugging purposes. When private syscall numbers are processed through the perf subsystem, the kernel fails to properly validate or sanitize these values, leading to unpredictable behavior in the kernel's memory management.
The technical implementation flaw occurs in the kernel's syscall tracing infrastructure where private syscall numbers are not adequately handled during perf event processing. This improper handling results in out-of-bounds memory reads that can trigger kernel OOPS conditions, effectively causing system crashes and denial of service. The vulnerability stems from the kernel's failure to properly validate syscall identifiers when they are processed through the performance monitoring subsystem, particularly when these identifiers fall outside the standard syscall number ranges. The flaw allows attackers to craft malicious applications that exploit the kernel's insufficient bounds checking, leading to memory corruption and system instability. According to CWE-129, this represents an implementation weakness involving insufficient validation of the length or size of input data, while the ATT&CK framework categorizes this under privilege escalation techniques that leverage kernel vulnerabilities.
The operational impact of CVE-2014-7825 extends beyond simple denial of service to include significant security implications through ASLR bypass capabilities. Local attackers can leverage this vulnerability to circumvent Address Space Layout Randomization protections that are fundamental to modern exploit mitigation strategies. This ASLR bypass occurs because the out-of-bounds read conditions can be manipulated to disclose kernel memory addresses, effectively leaking information about kernel layout and memory mappings. The vulnerability affects systems running Linux kernel versions up to 3.17.2, making it particularly relevant for older systems or those that have not received timely security updates. The exploit requires local system access but can be particularly dangerous in environments where privilege escalation is possible, as it could enable attackers to gain deeper system control. The perf subsystem, which is commonly enabled in production environments for performance monitoring, provides a legitimate attack surface that makes this vulnerability particularly concerning for system administrators.
Mitigation strategies for CVE-2014-7825 focus primarily on kernel updates and system hardening measures. The most effective solution involves upgrading to a patched kernel version where the syscall handling in trace_syscalls.c has been corrected to properly validate private syscall numbers. System administrators should prioritize applying security patches to all affected kernel versions, particularly in production environments where the perf subsystem is actively used. Additional mitigations include disabling the perf subsystem when not required, implementing proper access controls to limit local user privileges, and monitoring for suspicious syscall tracing activities. The vulnerability demonstrates the importance of proper input validation in kernel space code and highlights the need for comprehensive testing of system call handling mechanisms. Organizations should also consider implementing kernel module signing requirements and monitoring for unauthorized kernel modifications that could exacerbate the vulnerability's impact. Given the nature of the flaw, regular security audits of kernel subsystems and proper kernel configuration practices are essential for maintaining system integrity against similar vulnerabilities.