CVE-2005-2926 in Openserver
Summary
by MITRE
Stack-based buffer overflow in (1) backupsh and (2) authsh in SCO Openserver 5.0.7 allows local users to execute arbitrary code via a long HOME environment variable.
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Analysis
by VulDB Data Team • 07/12/2018
The vulnerability identified as CVE-2005-2926 represents a critical stack-based buffer overflow affecting SCO OpenServer 5.0.7 systems, specifically impacting two system utilities named backupsh and authsh. This flaw resides in the handling of environment variables, particularly the HOME variable, which serves as a fundamental component in Unix-like operating systems for user directory identification and path resolution. The vulnerability demonstrates a classic software security weakness where insufficient input validation permits maliciously crafted data to overwrite adjacent memory locations on the program stack, potentially leading to arbitrary code execution with elevated privileges.
The technical exploitation of this vulnerability occurs when a local user manipulates the HOME environment variable to exceed the allocated buffer space within the backupsh and authsh programs. These utilities, designed for system backup operations and authentication processes respectively, fail to properly validate the length of the HOME variable before copying it into fixed-size stack buffers. The CWE-121 classification applies here as the vulnerability involves stack-based buffer overflow conditions where the program writes beyond the bounds of allocated stack memory. When the HOME variable exceeds the predetermined buffer size, the excess data overflows into adjacent stack memory, potentially corrupting return addresses, function pointers, or other critical program state information that could be leveraged by an attacker to redirect program execution flow.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it provides attackers with the capability to execute arbitrary code with the privileges of the affected processes. The authsh utility typically operates with elevated permissions during authentication processes, while backupsh may run with system-level privileges during backup operations, making these targets particularly attractive for exploitation. Attackers could potentially use this vulnerability to gain unauthorized access to system resources, modify critical system files, or establish persistent backdoors within the OpenServer environment. The vulnerability affects systems running SCO OpenServer 5.0.7, which operates under the ATT&CK framework's privilege escalation and defense evasion tactics, specifically mapping to techniques involving local privilege escalation through software vulnerabilities and exploitation of system utilities.
Mitigation strategies for CVE-2005-2926 should prioritize immediate system patching from SCO to address the underlying buffer overflow conditions in both backupsh and authsh programs. Organizations should implement strict environment variable validation controls and consider employing stack protection mechanisms such as stack canaries or address space layout randomization to reduce exploitation success rates. System administrators should also conduct thorough security audits of all system utilities to identify similar buffer overflow vulnerabilities in other applications, as the vulnerability demonstrates a pattern of insufficient input validation in system-level programs. The ATT&CK framework suggests implementing process monitoring and anomaly detection to identify potential exploitation attempts, while the CWE taxonomy emphasizes the importance of input validation and secure coding practices to prevent similar issues in future software development cycles.