CVE-1999-0957 in MajorCool
Summary
by MITRE
majorcool mj_key_cache program allows local users to modify files via a symlink attack.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability identified as CVE-1999-0957 affects the majorcool mj_key_cache program, presenting a significant security risk through its susceptibility to symlink attacks. This issue manifests when local users exploit the program's handling of symbolic links to gain unauthorized access to modify files that they would normally not have permission to access. The flaw stems from inadequate validation of file system objects during program execution, creating an attack vector where malicious users can manipulate the program's behavior by creating carefully crafted symbolic links.
The technical implementation of this vulnerability operates through a classic race condition scenario where the mj_key_cache program performs operations that can be exploited by attackers who create symbolic links in strategic locations. When the program processes these links without proper verification of their target files, it inadvertently follows the symbolic links and modifies the underlying files they point to, rather than the intended cache files. This behavior directly violates the principle of least privilege and demonstrates a fundamental flaw in the program's file access controls.
From an operational perspective, this vulnerability allows local users to escalate their privileges and potentially compromise system integrity by modifying critical files through the cache program. The impact extends beyond simple file modification as attackers can leverage this weakness to alter configuration files, system binaries, or other sensitive resources that the cache program normally manages. The attack requires local system access but does not necessitate network connectivity or specialized tools, making it particularly dangerous in multi-user environments where privilege separation is essential.
Security practitioners should implement several mitigation strategies to address this vulnerability, including immediate patching of affected systems and the implementation of proper file system validation mechanisms within the mj_key_cache program. The solution involves ensuring that all file operations verify the actual file system object type before processing, preventing the program from following symbolic links to unintended targets. Organizations should also consider implementing mandatory access controls and regular security audits to detect similar weaknesses in other system components.
This vulnerability aligns with CWE-367, which addresses the Time-of-Check to Time-of-Use (TOCTOU) race condition, and represents a classic example of how insufficient input validation can lead to privilege escalation attacks. The ATT&CK framework categorizes this under privilege escalation techniques, specifically targeting local accounts and system services that lack proper file access controls. The vulnerability demonstrates the critical importance of implementing robust file system access controls and proper validation mechanisms in system utilities that handle file operations, particularly those that may be invoked by multiple users or processes.