CVE-2001-0401 in Solaris
Summary
by MITRE
Buffer overflow in tip in Solaris 8 and earlier allows local users to execute arbitrary commands via a long HOME environmental variable.
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Analysis
by VulDB Data Team • 01/04/2025
The vulnerability identified as CVE-2001-0401 represents a critical buffer overflow flaw within the tip utility of Solaris 8 and earlier operating systems. This issue specifically affects the handling of the HOME environment variable, creating a pathway for local attackers to escalate privileges and execute arbitrary code on affected systems. The tip utility, which serves as a terminal initialization program for serial communication, fails to properly validate the length of the HOME variable, allowing malicious input to overwrite adjacent memory regions. This fundamental flaw demonstrates a classic buffer overflow vulnerability that has been documented under CWE-121 in the Common Weakness Enumeration catalog, specifically categorized as "Stack-based Buffer Overflow" where insufficient bounds checking permits memory corruption. The vulnerability exists at the system level within the Solaris operating system's core utilities, making it particularly dangerous as it can be exploited by any local user with access to the system.
The technical implementation of this vulnerability stems from the improper handling of environment variables within the tip utility's initialization process. When the system processes the HOME environment variable, it does not perform adequate length validation or boundary checking before copying the variable's contents into a fixed-size buffer. This allows a maliciously crafted HOME variable, exceeding the allocated buffer space, to overwrite adjacent memory locations including return addresses and control data. Attackers can exploit this by crafting a sufficiently long HOME variable that overflows the buffer and injects malicious code or modifies the program's execution flow. The vulnerability is classified as a local privilege escalation issue under the MITRE ATT&CK framework, specifically mapping to technique T1068 which covers "Local Privilege Escalation" and T1059 which covers "Command and Scripting Interpreter" as the attack vector involves executing arbitrary commands through the compromised utility. The flaw is particularly insidious because it leverages the legitimate functionality of environment variables while exploiting the underlying memory management shortcomings in the system's implementation.
The operational impact of CVE-2001-0401 extends beyond simple privilege escalation to potentially compromise entire system security post-exploitation. Local attackers who successfully exploit this vulnerability can execute commands with the privileges of the tip utility process, which typically runs with elevated permissions due to its role in system initialization. This creates a significant risk for systems where the tip utility is used for critical serial communication tasks, as attackers could potentially gain unauthorized access to sensitive data or disrupt system operations. The vulnerability affects all Solaris 8 and earlier versions, representing a substantial portion of the deployed systems at the time of discovery, making it a high-priority target for exploitation. Organizations running these older Solaris versions faced a critical security gap where a simple environment variable manipulation could lead to full system compromise, as the attack requires no network connectivity and only local system access.
Mitigation strategies for CVE-2001-0401 primarily focus on system updates and immediate patching of affected Solaris versions. The most effective solution involves upgrading to Solaris 9 or later versions where the vulnerability has been addressed through proper buffer validation mechanisms. System administrators should also implement immediate hardening measures such as restricting environment variable manipulation and monitoring for unusual HOME variable lengths in system logs. The vulnerability can be mitigated through environment variable length restrictions and by implementing proper input validation in all system utilities that process environment variables. Organizations should also consider implementing privilege separation mechanisms and monitoring for unauthorized access attempts to system initialization utilities. According to industry best practices and the National Institute of Standards and Technology guidelines, this vulnerability requires immediate attention as it represents a critical security flaw that can be exploited without requiring specialized tools or network access. Regular system auditing and vulnerability assessment procedures should include checks for outdated Solaris versions and proper implementation of environment variable handling across all system utilities to prevent similar buffer overflow vulnerabilities from being exploited in the future.