CVE-2017-14140 in Android
Summary
by MITRE
The move_pages system call in mm/migrate.c in the Linux kernel before 4.12.9 doesn t check the effective uid of the target process, enabling a local attacker to learn the memory layout of a setuid executable despite ASLR.
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Analysis
by VulDB Data Team • 01/20/2023
The vulnerability identified as CVE-2017-14140 resides within the Linux kernel's memory management subsystem, specifically in the move_pages system call implementation located in mm/migrate.c. This flaw represents a critical security weakness that undermines the fundamental security model of modern operating systems by allowing unauthorized information disclosure. The vulnerability affects Linux kernel versions prior to 4.12.9, creating a persistent risk for systems running these older versions. The issue stems from inadequate privilege validation within the kernel's memory management interface, where the system call fails to properly verify the effective user identifier of target processes before executing memory relocation operations.
The technical flaw manifests when a local attacker exploits the move_pages system call to query memory layout information from setuid executables. This occurs because the kernel does not validate whether the calling process has sufficient privileges to access the memory mappings of target processes, particularly those running with elevated privileges. The vulnerability specifically targets the privilege checking mechanism that should prevent non-privileged processes from inspecting memory layouts of processes owned by different users. This weakness enables attackers to bypass Address Space Layout Randomization protections, which are fundamental to modern exploit mitigation strategies. The flaw operates at the kernel level, making it particularly dangerous as it can be exploited without requiring network connectivity or remote access to the target system.
The operational impact of this vulnerability extends beyond simple information disclosure, creating significant risks for systems running setuid binaries and applications that rely on memory protection mechanisms. Attackers can leverage this vulnerability to gather detailed memory layout information, including base addresses of memory segments, stack locations, and heap organization patterns. This intelligence directly undermines the effectiveness of ASLR implementations, which are designed to randomize memory layouts to prevent exploitation of memory corruption vulnerabilities. The vulnerability essentially allows attackers to perform reconnaissance against setuid processes, potentially enabling more sophisticated attacks such as return-oriented programming or other memory corruption exploits that depend on knowing specific memory addresses. This makes systems more vulnerable to privilege escalation attacks and other advanced exploitation techniques that require detailed knowledge of process memory structures.
Mitigation strategies for CVE-2017-14140 primarily focus on upgrading to Linux kernel versions 4.12.9 or later, where the vulnerability has been addressed through proper privilege validation in the move_pages system call implementation. System administrators should prioritize patching affected systems and implementing comprehensive kernel update schedules to prevent exploitation of this and similar vulnerabilities. Additional defensive measures include monitoring for unauthorized access attempts to setuid processes, implementing strict process monitoring, and ensuring that only necessary setuid binaries are present on systems. The vulnerability aligns with CWE-284, which addresses improper access control, and maps to ATT&CK technique T1068, which involves local privilege escalation through kernel vulnerabilities. Organizations should also consider implementing kernel lockdown mechanisms and restricting local user access to minimize the potential impact of such vulnerabilities, particularly in environments where multiple users share system resources.