CVE-1999-1114 in IRIX
Summary
by MITRE
Buffer overflow in Korn Shell (ksh) suid_exec program on IRIX 6.x and earlier, and possibly other operating systems, allows local users to gain root privileges.
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Analysis
by VulDB Data Team • 09/04/2024
The vulnerability described in CVE-1999-1114 represents a critical buffer overflow flaw within the Korn Shell's suid_exec program that affects IRIX 6.x and earlier versions, with potential impact on other operating systems. This issue arises from improper input validation in the handling of command-line arguments passed to the suid_exec program, which is responsible for executing commands with elevated privileges. The flaw exists in the way the program processes user-supplied input, specifically when dealing with long argument strings that exceed the allocated buffer space, creating a condition where malicious input can overwrite adjacent memory locations.
The technical implementation of this vulnerability leverages the suid bit functionality of the ksh program, which normally executes with root privileges to allow users to perform administrative tasks. When a local user invokes the vulnerable program with carefully crafted arguments that exceed the buffer limits, the overflow can overwrite the return address on the stack or other critical control data structures. This memory corruption enables an attacker to redirect program execution flow and ultimately execute arbitrary code with root privileges, effectively bypassing normal access controls and gaining complete system control. The vulnerability is classified as a buffer overflow under CWE-121, which specifically addresses stack-based buffer overflow conditions that can be exploited to execute arbitrary code.
From an operational perspective, this vulnerability presents a severe risk to system security as it allows local privilege escalation without requiring remote network access. The attack vector is particularly dangerous because it requires no special network connectivity and can be exploited by any local user who has access to the system. The impact extends beyond simple privilege escalation to include complete system compromise, data theft, and potential persistence mechanisms that could allow attackers to maintain access even after system reboots. The vulnerability's exploitation can result in unauthorized system administration capabilities, making it a prime target for attackers seeking to establish persistent access to compromised systems.
The mitigation strategies for this vulnerability should include immediate patching of affected systems with updated versions of the Korn Shell that properly validate input lengths and implement proper buffer management techniques. System administrators should also implement additional security controls such as disabling unnecessary suid programs, monitoring for suspicious execution patterns, and applying the principle of least privilege to limit local user access. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically leveraging the T1068 - Exploitation for Privilege Escalation tactic. Organizations should also consider implementing runtime protections such as stack canaries, address space layout randomization, and non-executable stack protections to prevent exploitation even if patches are not immediately available. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow vulnerabilities in other system components, as this class of flaw remains prevalent in legacy software implementations.