CVE-2001-0686 in Solaris
Summary
by MITRE
Buffer overflow in mail included with SunOS 5.8 for x86 allows a local user to gain privileges via a long HOME environment variable.
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Analysis
by VulDB Data Team • 08/27/2019
The vulnerability described in CVE-2001-0686 represents a classic buffer overflow condition affecting the mail utility distributed with SunOS 5.8 for x86 architectures. This flaw resides in the handling of environment variables, specifically the HOME environment variable, which serves as a critical component in Unix-like operating systems for determining user home directories and associated configuration settings. The buffer overflow occurs when the mail utility processes an excessively long HOME environment variable, leading to memory corruption that can be exploited by local attackers to escalate privileges. The vulnerability is particularly concerning because it operates within the context of a local user attack, meaning an attacker must already have access to the system but can leverage this weakness to gain elevated privileges. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows data to overwrite adjacent memory locations, potentially including return addresses or other critical program state information.
The operational impact of CVE-2001-0686 extends beyond simple privilege escalation, as it represents a fundamental security weakness in the system's environment variable handling mechanisms. When a local user crafts a sufficiently long HOME environment variable, the mail utility's buffer management fails to properly validate input length, causing the program to write beyond allocated memory boundaries. This memory corruption can lead to arbitrary code execution, allowing the attacker to execute commands with elevated privileges. The vulnerability is particularly dangerous in multi-user environments where local access might be obtained through various means such as legitimate user accounts or compromised credentials. From an attack perspective, this weakness aligns with ATT&CK technique T1068 which involves exploiting vulnerabilities to gain elevated privileges, and T1059 which covers command and scripting interpreters. The attack vector requires local system access but provides a pathway to privilege escalation that can significantly compromise system integrity and confidentiality.
Mitigation strategies for CVE-2001-0686 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves applying the vendor-supplied security patches that address the buffer overflow in the mail utility's environment variable handling. System administrators should also implement environment variable length restrictions to prevent excessively long HOME variables from being processed by critical system utilities. Additionally, privilege separation mechanisms should be strengthened to ensure that even if an attacker successfully exploits this vulnerability, the damage remains contained. The implementation of stack canaries, address space layout randomization, and other exploit mitigation techniques can further reduce the effectiveness of buffer overflow attacks. Organizations should also conduct regular security assessments to identify similar vulnerabilities in other system utilities and ensure proper input validation is implemented across all components handling user-supplied data. Compliance with security standards such as those outlined in the NIST Cybersecurity Framework and ISO 27001 can help establish comprehensive security controls that address both immediate vulnerabilities and broader system security posture improvements.