CVE-2017-5123 in Linux
Summary
by MITRE • 11/03/2021
Insufficient data validation in waitid allowed an user to escape sandboxes on Linux.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2017-5123 represents a critical sandbox escape flaw in Linux kernel implementations that specifically affects the waitid system call. This issue stems from inadequate input validation within the kernel's process management subsystem, where the waitid function fails to properly sanitize or validate the data provided by user-space applications. The vulnerability exists in the kernel's handling of process status information retrieval, particularly when dealing with specific combinations of process identifiers and wait options that should be strictly controlled. Attackers can exploit this weakness to manipulate kernel memory structures and bypass security boundaries that are normally enforced by sandboxing mechanisms.
The technical flaw manifests when user-space applications invoke waitid with malformed or unexpected parameters that the kernel does not properly validate before processing. This insufficient validation creates a pathway for privilege escalation and arbitrary code execution within kernel space. The vulnerability is particularly dangerous because it allows unprivileged users to potentially gain elevated privileges or execute code with kernel-level permissions, effectively undermining the fundamental security model of Linux systems. The flaw operates through a combination of memory corruption techniques and improper access control enforcement that enables attackers to manipulate kernel data structures.
The operational impact of CVE-2017-5123 extends beyond simple sandbox bypass to potentially enable full system compromise when combined with other exploitation techniques. Systems running affected kernel versions become vulnerable to privilege escalation attacks that can be leveraged by malicious users to gain root access or execute arbitrary code with kernel privileges. This vulnerability particularly affects containerized environments and sandboxed applications where the kernel's security boundaries are expected to prevent unauthorized access to system resources. The exploitation of this vulnerability can result in complete system compromise, data exfiltration, and persistent backdoor establishment within compromised environments.
Mitigation strategies for CVE-2017-5123 primarily focus on kernel updates and system hardening measures. Organizations should immediately apply the relevant kernel patches provided by their distribution vendors to address the validation flaw in the waitid system call. Additionally, implementing proper kernel hardening configurations including disabling unnecessary system calls, enforcing strict access controls, and deploying kernel module signing policies can help reduce the attack surface. System administrators should also consider implementing monitoring solutions that can detect anomalous waitid system call usage patterns or suspicious kernel memory access patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-129 and CWE-787 categories related to insufficient input validation and out-of-bounds writes, and represents a technique commonly mapped to ATT&CK tactics involving privilege escalation and defense evasion through kernel exploitation.