CVE-1999-0988 in UnixWare
Summary
by MITRE
UnixWare pkgtrans allows local users to read arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-1999-0988 affects the UnixWare operating system's pkgtrans utility, which is used for package management and installation operations. This flaw represents a classic symlink attack vector that exploits improper handling of symbolic links during file operations. The pkgtrans utility, designed to facilitate software package transfers and installations, fails to adequately validate or sanitize symbolic link references, creating a pathway for local attackers to access files they should not be able to read. This vulnerability specifically targets the privilege escalation and information disclosure capabilities available to local users who can manipulate the file system during package processing operations.
The technical implementation of this vulnerability stems from the pkgtrans utility's insecure handling of symbolic links when processing package files. When the utility encounters a symbolic link during package extraction or installation, it does not properly verify the target of the link before attempting to read or process the referenced file. This allows an attacker with local access to create malicious symbolic links that point to sensitive system files such as password databases, configuration files, or other restricted resources. The flaw operates under the principle of insecure file handling where the system assumes that symbolic links point to legitimate locations without proper validation. This behavior aligns with CWE-367, which describes the dangerous use of symbolic links in file operations, and represents a direct violation of proper file system access controls that should prevent unauthorized reading of system resources.
The operational impact of this vulnerability extends beyond simple information disclosure, as local users can leverage this flaw to access sensitive system data that may contain authentication credentials, system configurations, or other confidential information. Attackers can use this capability to escalate privileges by reading system files such as /etc/passwd, /etc/shadow, or other critical configuration data that would normally be restricted. The vulnerability is particularly concerning in multi-user environments where local access might be granted to less privileged users who could exploit this weakness to gain unauthorized access to system resources. The attack requires local system access and the ability to manipulate the file system during package operations, making it a privilege escalation vulnerability that could be combined with other attack vectors to achieve more significant system compromise.
Mitigation strategies for this vulnerability should focus on implementing proper file system validation and access control mechanisms within the pkgtrans utility. System administrators should ensure that package management operations are performed with appropriate privileges and that symbolic link handling is properly validated before file access occurs. The recommended approach involves updating the pkgtrans utility to implement proper symlink resolution checks that verify the target of symbolic links against expected file system locations. Additionally, implementing proper file permissions and access controls can help limit the damage that can be achieved through such attacks. Organizations should also consider implementing least privilege principles for package management operations and regularly audit system configurations to prevent unauthorized symbolic link creation. This vulnerability highlights the importance of secure coding practices and proper input validation in system utilities, particularly those that handle file system operations with elevated privileges, and aligns with ATT&CK technique T1068 which covers the use of local privilege escalation techniques through system utility manipulation.