CVE-2007-0823 in Linux
Summary
by MITRE
xterm on Slackware Linux 10.2 stores information that had been displayed for a different user account using the same xterm process, which might allow local users to bypass file permissions and read other users files, or obtain other sensitive information, by reading the xterm process memory. NOTE: it could be argued that this is an expected consequence of multiple users sharing the same interactive process, in which case this is not a vulnerability.
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Analysis
by VulDB Data Team • 08/19/2018
The vulnerability identified as CVE-2007-0823 affects xterm terminal emulator running on Slackware Linux 10.2 systems where multiple user accounts share the same xterm process instance. This represents a significant security concern within multi-user environments where process memory management fails to properly isolate data between different user sessions. The flaw stems from xterm's improper handling of memory allocation and user context switching when multiple users utilize the same terminal process, creating a scenario where sensitive information from one user's session can persist in memory and potentially be accessed by subsequent users. This type of vulnerability falls under the category of information exposure through process memory manipulation and aligns with CWE-200, which addresses the exposure of sensitive information through improper access control mechanisms.
The technical implementation of this vulnerability relies on the shared memory characteristics of xterm processes when multiple users interact with the same terminal session. When a user exits an xterm session, the process memory containing previously displayed content may not be properly cleared or sanitized before another user begins using the same process. This creates an attack surface where malicious users could potentially read cached data from previous sessions, including file contents, command outputs, or other sensitive information that was displayed within the terminal. The vulnerability exploits the fundamental assumption that process memory isolation should prevent cross-user data leakage, which in this case fails to maintain proper boundaries between different user contexts. The attack vector operates through direct memory inspection techniques and demonstrates a failure in proper process cleanup and memory management practices.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable privilege escalation and unauthorized data access within shared computing environments. Local users with access to the same xterm process could exploit this flaw to read files they would normally not have permission to access, effectively bypassing traditional file permission controls. This scenario becomes particularly dangerous in multi-user systems where users might share terminal sessions or when administrators fail to properly manage user sessions. The vulnerability undermines the security model of Unix-like systems where process isolation and proper access controls are fundamental to maintaining security boundaries between users. According to ATT&CK framework category T1005, this represents a data hijacking technique where adversaries gain access to sensitive information through process memory manipulation, potentially leading to broader system compromise.
Mitigation strategies for CVE-2007-0823 require implementing proper process isolation mechanisms and ensuring that xterm properly clears memory content between user sessions. System administrators should enforce strict user session management protocols, ensuring that each user operates within their own dedicated terminal process rather than sharing sessions. The most effective approach involves configuring xterm to properly reset memory buffers upon user logout and implementing proper memory sanitization procedures. Additionally, organizations should consider upgrading to newer versions of xterm that have addressed this memory management issue, as the vulnerability exists due to outdated implementation practices. Regular security audits should verify that terminal emulators properly handle user context switching and memory cleanup operations. The vulnerability highlights the importance of proper memory management in multi-user systems and reinforces the need for security-conscious development practices that ensure process isolation and proper resource cleanup. Organizations should also implement monitoring mechanisms to detect unusual memory access patterns that might indicate exploitation attempts.