CVE-2001-0652 in Solaris
Summary
by MITRE
Heap overflow in xlock in Solaris 2.6 through 8 allows local users to gain root privileges via a long (1) XFILESEARCHPATH or (2) XUSERFILESEARCHPATH environmental variable.
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Analysis
by VulDB Data Team • 01/05/2025
The vulnerability described in CVE-2001-0652 represents a critical heap overflow condition within the xlock utility distributed with Solaris operating systems version 2.6 through 8. This flaw exists in the handling of specific X11 environment variables that control file search paths for user and system resources. The xlock program, designed to lock the X11 display when a user is away from their workstation, contains a buffer overflow vulnerability that can be exploited by local attackers to escalate privileges to root level access.
The technical mechanism behind this vulnerability involves the improper handling of environment variables XFILESEARCHPATH and XUSERFILESEARCHPATH within the xlock application. These variables are used by X11 applications to specify directories where configuration files and resources should be searched. When a malicious user sets these variables to excessively long values, the xlock program fails to properly validate the input length before copying it into a fixed-size heap buffer. This classic buffer overflow condition allows an attacker to overwrite adjacent memory locations, potentially including return addresses and control data structures that govern program execution flow.
The operational impact of this vulnerability extends beyond simple privilege escalation to represent a significant security risk for Solaris systems in multi-user environments. Local users who can execute the xlock program or modify the environment variables can leverage this flaw to gain root access to the system, effectively bypassing all user-level security controls. The vulnerability affects a broad range of Solaris versions, making it particularly dangerous as administrators would need to patch multiple system versions to fully protect against exploitation. This type of vulnerability aligns with CWE-121, which specifically addresses stack-based buffer overflow conditions, though in this case the overflow occurs in heap memory rather than stack memory.
The exploitation of this vulnerability demonstrates the importance of proper input validation and memory management in system utilities. The ATT&CK framework categorizes this as a privilege escalation technique through the use of vulnerable system components, specifically targeting the execution of programs with elevated privileges. The fact that this vulnerability exists in a utility designed for security purposes - locking displays - makes it particularly concerning as attackers can exploit it to gain root access while appearing to be performing legitimate system maintenance tasks.
Mitigation strategies for this vulnerability require immediate patching of affected Solaris versions with the appropriate security updates provided by Sun Microsystems. System administrators should also implement monitoring for unusual environment variable modifications and consider restricting the ability to modify these specific variables in system-wide configurations. Additionally, the principle of least privilege should be enforced by ensuring that only authorized users can execute programs that might be vulnerable to such exploits, and that system utilities are regularly audited for similar memory handling issues. The vulnerability serves as a reminder of the critical importance of secure coding practices and thorough input validation in system-level programs that may be executed with elevated privileges.