CVE-2002-0987 in OpenUnix
Summary
by MITRE
X server (Xsco) in OpenUNIX 8.0.0 and UnixWare 7.1.1 does not drop privileges before calling programs such as xkbcomp using popen, which could allow local users to gain privileges.
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Analysis
by VulDB Data Team • 02/27/2025
The vulnerability identified as CVE-2002-0987 resides within the X server implementation known as Xsco found in OpenUNIX 8.00 and UnixWare 7.1.1 operating systems. This flaw represents a critical privilege escalation issue that stems from improper privilege handling during program execution sequences. The vulnerability specifically affects the X server's approach to executing external programs through the popen function call, creating an exploitable condition that local attackers can leverage to elevate their system privileges.
The technical flaw manifests when the X server process executes external commands such as xkbcomp without properly dropping its elevated privileges first. This design oversight allows the system to maintain root or administrative privileges while invoking external programs, creating a pathway for privilege escalation. The popen function, which is used to establish pipes for communication between processes, becomes a critical attack vector when executed within a privileged context. According to CWE-276, this vulnerability directly relates to improper privileges, specifically CWE-276 which addresses incorrect permissions and access control. The X server's failure to drop privileges before executing external programs creates a scenario where malicious input or code injection can be executed with elevated privileges, effectively bypassing normal security boundaries.
The operational impact of this vulnerability is significant as it provides local users with the ability to gain root privileges on affected systems. Attackers can exploit this condition by manipulating the X server's execution flow to execute arbitrary commands with elevated permissions, potentially leading to complete system compromise. The vulnerability affects systems where users have local access to the X server environment, making it particularly dangerous in multi-user environments where unauthorized users might attempt to exploit this weakness. This privilege escalation capability undermines the fundamental security model of Unix-like systems, where privilege separation is crucial for maintaining system integrity and preventing unauthorized access to sensitive resources.
Security mitigations for this vulnerability should focus on implementing proper privilege dropping mechanisms before executing external programs through popen calls. System administrators should ensure that the X server process drops its elevated privileges immediately before invoking external commands such as xkbcomp. The recommended approach aligns with the principle of least privilege and follows ATT&CK framework technique T1068 which addresses privilege escalation through the use of popen functions and similar system calls. Updates and patches from the vendor should be applied immediately to address this vulnerability, and system configurations should be reviewed to ensure that no unnecessary privileges are maintained during external program execution. Additionally, monitoring for suspicious X server activity and implementing proper access controls can help detect and prevent exploitation attempts. The vulnerability highlights the importance of secure coding practices and privilege management in system-level applications, particularly those handling user input or executing external processes within privileged contexts.