CVE-2001-1478 in UnixWare
Summary
by MITRE
Buffer overflow in xlock in UnixWare 7.1.0 and 7.1.1 and Open Unix 8.0.0 allows local users to execute arbitrary code.
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Analysis
by VulDB Data Team • 04/10/2019
The vulnerability identified as CVE-2001-1478 represents a critical buffer overflow flaw within the xlock utility of certain Unix operating systems including UnixWare 7.1.0 and 7.1.1 along with Open Unix 8.0.0. This issue arises from inadequate input validation mechanisms within the xlock program that fails to properly check the length of user-supplied data before copying it into fixed-size memory buffers. The buffer overflow condition occurs when the program processes command-line arguments or configuration inputs without sufficient bounds checking, allowing maliciously crafted input to overwrite adjacent memory locations. This particular vulnerability resides in the xlock utility which is commonly used to lock terminal sessions and prevent unauthorized access to systems when users step away from their workstations. The flaw is classified as a local privilege escalation vulnerability since it requires an attacker to already have access to the system to exploit it, though it can potentially be leveraged to gain elevated privileges or execute arbitrary code within the context of the running process. According to CWE classification, this vulnerability maps to CWE-121 which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The operational impact of this vulnerability extends beyond simple code execution as it can potentially allow attackers to bypass authentication mechanisms, escalate privileges, or even compromise the entire system if the xlock utility runs with elevated privileges. The xlock program typically operates with sufficient permissions to interact with system resources and display graphical interfaces, making it an attractive target for exploitation. This vulnerability aligns with ATT&CK technique T1068 which describes the exploitation of legitimate credentials and system utilities to gain unauthorized access or escalate privileges. The attack vector for this vulnerability requires local system access and involves crafting specific input parameters that cause the buffer overflow to occur during normal program execution. The memory corruption resulting from this overflow can lead to unpredictable program behavior, crashes, or more dangerously, provide attackers with opportunities to inject and execute malicious code. The vulnerability demonstrates a classic lack of proper input sanitization and memory management practices that were common in system utilities of that era. Security researchers have noted that this type of buffer overflow in system utilities represents a significant risk because these programs often run with elevated privileges and are frequently executed by users during normal system operation. The exploitation of this vulnerability typically involves crafting input that exceeds the buffer capacity, causing data to overwrite critical program memory structures such as return addresses or function pointers. This allows attackers to redirect program execution flow and execute malicious code with the privileges of the running process. The vulnerability was particularly concerning in enterprise environments where Unix systems were prevalent and xlock was commonly used for session management. Mitigation strategies for CVE-2001-1478 include applying vendor patches that implement proper bounds checking and input validation mechanisms within the xlock utility. System administrators should also consider disabling or removing the xlock utility if it is not essential for their security policies, as this eliminates the attack surface entirely. Additionally, implementing proper access controls and privilege separation can limit the potential impact of successful exploitation attempts. The vulnerability serves as a reminder of the importance of secure coding practices and proper input validation in system utilities, particularly those that handle user input and operate with elevated privileges. Organizations should conduct regular vulnerability assessments and security audits to identify similar buffer overflow conditions in other system components and applications. The remediation process should include not only patching the specific vulnerability but also reviewing and strengthening overall code quality standards to prevent similar issues from occurring in other system utilities. This particular vulnerability highlights the need for comprehensive security testing and code review processes that can identify buffer overflow conditions before they can be exploited by malicious actors.