CVE-1999-0099 in Solaris
Summary
by MITRE
buffer overflow in syslog utility allows local or remote attackers to gain root privileges.
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Analysis
by VulDB Data Team • 04/03/2025
The vulnerability identified as CVE-1999-0099 represents a critical buffer overflow flaw within the syslog utility that affects Unix-based systems. This vulnerability resides in the way the syslog daemon processes log messages, specifically when handling overly long input strings that exceed the allocated buffer space. The flaw allows attackers to manipulate the program execution flow by overwriting adjacent memory locations, potentially leading to arbitrary code execution with elevated privileges. The vulnerability is particularly dangerous because it can be exploited both locally and remotely, making it a significant threat to system integrity and security.
The technical implementation of this buffer overflow occurs during the parsing of log messages where the syslog utility fails to properly validate input length before copying data into fixed-size buffers. When an attacker sends a specially crafted log message containing excessive data, the program overflows the allocated buffer and begins overwriting adjacent memory regions including return addresses and control data. This memory corruption can be exploited to redirect program execution to malicious code placed by the attacker, typically resulting in privilege escalation to the root user level. The vulnerability directly maps to CWE-121, which describes buffer overflow conditions where insufficient boundary checking allows data to overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete system control. Once root privileges are gained, attackers can modify system files, install backdoors, steal sensitive data, or establish persistent access to the compromised system. The vulnerability affects systems running various Unix implementations including but not limited to solaris, hp-ux, and other unix-based operating systems that utilize the vulnerable syslog implementation. The remote exploitation capability means that attackers do not need physical access to the system, making this vulnerability particularly dangerous for network-connected systems and servers.
System administrators should implement immediate mitigations including applying vendor patches and updates, disabling unnecessary network services that might expose the syslog daemon, and implementing network segmentation to limit exposure. The use of intrusion detection systems can help detect exploitation attempts through anomalous log message patterns. Additionally, implementing proper input validation and boundary checking in system utilities represents a fundamental defense mechanism against such buffer overflow vulnerabilities. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically focusing on the use of system utilities for gaining elevated access. Regular security audits and code reviews should emphasize buffer handling practices and proper memory management to prevent similar vulnerabilities from being introduced in future system implementations.