CVE-2001-0190 in Solaris
Summary
by MITRE
Buffer overflow in /usr/bin/cu in Solaris 2.8 and earlier, and possibly other operating systems, allows local users to gain privileges by executing cu with a long program name (arg0).
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Analysis
by VulDB Data Team • 08/23/2019
The vulnerability described in CVE-2001-0190 represents a classic buffer overflow flaw located in the /usr/bin/cu utility, which is part of the Solaris operating system family. This utility serves as a terminal program for connecting to remote systems and is commonly used for modem communications. The issue affects Solaris 2.8 and earlier versions, though it may potentially impact other operating systems that utilize similar implementations. The vulnerability stems from inadequate input validation within the program's argument handling mechanism, specifically when processing the program name argument.
The technical flaw manifests when a local user executes the cu program with an excessively long argument string passed as arg0, which corresponds to the program name. This condition creates a buffer overflow scenario where the program attempts to store more data in a fixed-length buffer than it can accommodate. The overflow occurs in the command line argument processing code within the cu utility, where the program name is copied into a statically allocated buffer without proper bounds checking. This buffer overflow vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and potentially CWE-122 for heap-based buffer overflows if the implementation uses dynamic memory allocation.
The operational impact of this vulnerability is significant as it allows local users to escalate their privileges on affected systems. When exploited successfully, the buffer overflow can overwrite critical memory locations including return addresses, stack canaries, or other control data structures within the cu program's execution context. This privilege escalation capability means that a regular user could potentially gain root access to the system, which would provide complete control over system resources, file access, and administrative functions. The vulnerability is particularly concerning because it requires only local system access to exploit, making it accessible to users who may not have administrative privileges initially.
The exploitation of this vulnerability aligns with ATT&CK technique T1068, which involves the use of privilege escalation techniques through local exploits. Attackers could leverage this condition to execute arbitrary code with elevated privileges, potentially leading to persistent access, data theft, or system compromise. The attack surface is relatively narrow since it requires the user to execute the cu program with malicious arguments, but the impact is severe given the potential for privilege escalation. System administrators should note that this vulnerability is particularly dangerous in environments where users have local access to systems running vulnerable versions of Solaris, as it could be exploited to establish backdoors or exfiltrate sensitive data. Mitigation strategies include applying vendor patches, upgrading to non-vulnerable versions of Solaris, implementing proper input validation controls, and restricting local execution privileges for the cu utility to minimize the attack surface.
The vulnerability demonstrates the critical importance of proper input validation in system utilities and highlights how seemingly benign programs can contain dangerous security flaws. It serves as a reminder of the need for comprehensive security testing of system components, particularly those that handle user input in privileged contexts. Organizations should implement robust security practices including regular vulnerability assessments, patch management procedures, and security monitoring to prevent exploitation of such buffer overflow conditions. The incident also underscores the necessity of following secure coding practices that prevent buffer overflows through techniques such as bounds checking, use of safe string handling functions, and proper memory management protocols.