CVE-2001-1384 in Linux
Summary
by MITRE
ptrace in Linux 2.2.x through 2.2.19, and 2.4.x through 2.4.9, allows local users to gain root privileges by running ptrace on a setuid or setgid program that itself calls an unprivileged program, such as newgrp.
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Analysis
by VulDB Data Team • 10/27/2024
The vulnerability described in CVE-2001-1384 represents a critical privilege escalation flaw within the Linux kernel's ptrace system call implementation. This vulnerability exists in kernel versions 2.2.x through 2.2.19 and 2.4.x through 2.4.9, where the ptrace mechanism fails to properly validate the security context when tracing processes that have elevated privileges. The flaw specifically manifests when a local user can execute ptrace against a setuid or setgid program that subsequently invokes an unprivileged program, creating a pathway for privilege escalation. The technical root cause lies in the insufficient access control checks within the ptrace subsystem that should prevent a lower-privileged user from manipulating processes with elevated capabilities.
The operational impact of this vulnerability is severe as it allows any local user to potentially gain root privileges on affected systems. When a user runs ptrace on a setuid program such as newgrp, which is designed to change group memberships and typically runs with elevated privileges, the vulnerability enables the tracing user to manipulate the execution flow and potentially escalate their privileges. This occurs because the kernel's ptrace implementation does not adequately enforce security boundaries between processes with different privilege levels, particularly when one process calls another that operates at a different privilege context. The vulnerability essentially undermines the fundamental security model of Unix-like systems where setuid programs are expected to maintain their elevated privileges while being traced by other users.
This vulnerability maps directly to CWE-276, which describes improper privilege management in operating systems, and aligns with ATT&CK technique T1068, which covers local privilege escalation through system call manipulation. The flaw demonstrates how kernel-level security mechanisms can be bypassed when proper privilege validation is not enforced during inter-process communication. The attack vector requires local system access and knowledge of the specific setuid program pattern, but once exploited, it provides complete system compromise. Security researchers have noted that this vulnerability was particularly dangerous because it exploited the trust model between different system components, where the kernel failed to properly enforce the principle of least privilege during ptrace operations. The vulnerability highlights the critical importance of kernel security auditing and proper privilege boundary enforcement in operating system design.
The recommended mitigations include immediate kernel updates to versions that patch this vulnerability, typically kernel versions 2.2.20 and 2.4.10 or later. System administrators should also implement strict access controls on setuid programs and consider disabling ptrace operations for untrusted users through appropriate kernel parameters. Additionally, monitoring and logging of ptrace system calls can help detect potential exploitation attempts. Organizations should conduct thorough security assessments to identify vulnerable systems and ensure all kernel components are kept up to date with security patches. The vulnerability underscores the necessity of comprehensive kernel security reviews and the importance of maintaining current security configurations to prevent exploitation of similar privilege escalation flaws.