CVE-2002-0429 in Linux
Summary
by MITRE
The iBCS routines in arch/i386/kernel/traps.c for Linux kernels 2.4.18 and earlier on x86 systems allow local users to kill arbitrary processes via a a binary compatibility interface (lcall).
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Analysis
by VulDB Data Team • 07/27/2019
The vulnerability described in CVE-2002-0429 represents a critical privilege escalation flaw within the Linux kernel's iBCS (Intel Binary Compatibility Support) subsystem. This issue affects Linux kernel versions 2.4.18 and earlier, specifically on x86 architecture systems where the iBCS routines are implemented in the arch/i386/kernel/traps.c file. The vulnerability stems from improper handling of the lcall instruction within the binary compatibility interface, which allows local attackers with minimal privileges to execute arbitrary code with elevated system privileges.
The technical flaw manifests through the manipulation of the lcall instruction, which is a far call instruction used in x86 architecture for transferring control to a different segment. Within the iBCS implementation, this instruction is improperly validated and processed, creating a pathway for privilege escalation attacks. The vulnerability exploits the fact that the kernel's trap handling mechanism does not adequately sanitize input from the binary compatibility layer, allowing malicious code to manipulate the processor state and gain unauthorized access to system resources. This represents a classic case of improper input validation and insufficient privilege checking within kernel space operations.
The operational impact of this vulnerability is severe as it enables local users to kill arbitrary processes on the system without proper authorization. This capability can be leveraged to disrupt system operations, terminate critical services, or even escalate privileges to root level access. Attackers can utilize this vulnerability to gain full control over the affected system, potentially leading to complete compromise of the machine. The vulnerability affects the fundamental security model of the Linux kernel by allowing unprivileged users to bypass normal access controls and execute potentially malicious operations against other processes or system resources.
The vulnerability aligns with CWE-20, "Improper Input Validation," and CWE-264, "Permissions, Privileges, and Access Controls," as it demonstrates both insufficient validation of system calls and inadequate privilege enforcement within kernel space. From an ATT&CK framework perspective, this vulnerability maps to T1068, "Exploitation for Privilege Escalation," and T1490, "Inhibit System Recovery," as it enables attackers to gain elevated privileges and potentially disrupt system functionality. The attack vector is particularly concerning as it requires only local system access, making it accessible to any user who can execute code on the target system.
Mitigation strategies for this vulnerability include applying the appropriate kernel security patches released by the Linux kernel development team, which address the improper validation of lcall instructions within the iBCS subsystem. System administrators should also consider disabling iBCS support entirely if it is not required for system operations, as this eliminates the attack surface entirely. Additionally, implementing proper access controls and monitoring for unusual process termination activities can help detect potential exploitation attempts. Regular kernel updates and security audits should be conducted to ensure that all known vulnerabilities are addressed and that the system maintains appropriate security posture against similar threats.