CVE-1999-1022 in IRIX
Summary
by MITRE
serial_ports administrative program in IRIX 4.x and 5.x trusts the user's PATH environmental variable to find and execute the ls program, which allows local users to gain root privileges via a Trojan horse ls program.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability described in CVE-1999-1022 represents a classic privilege escalation flaw affecting IRIX operating systems version 4.x and 5.x. This issue resides within the serial_ports administrative program which is designed to manage serial port configurations on these systems. The program's design flaw stems from its improper handling of the PATH environment variable during the execution of the ls command, creating a dangerous trust relationship between the program and user-controlled system paths. This vulnerability specifically targets the administrative utilities of IRIX systems, making it particularly concerning for system administrators who rely on these tools for critical system management tasks.
The technical exploitation mechanism of this vulnerability operates through a Trojan horse attack vector where a local user can manipulate the PATH environment variable to point to a maliciously crafted ls program instead of the legitimate system utility. When the serial_ports program executes ls, it follows the user's PATH specification rather than using absolute paths to system binaries. This behavior directly violates the principle of least privilege and allows attackers to substitute their malicious program for the legitimate ls utility. The flaw essentially creates a race condition or path manipulation scenario where the attacker's program is executed with the elevated privileges of the serial_ports program, which typically runs with root permissions. This vulnerability aligns with CWE-276, which describes improper privileges in the context of command execution, and represents a classic example of insecure direct object reference in system administration tools.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows local users to effectively gain complete root access to IRIX systems without requiring any special authentication or network connectivity. Attackers can leverage this flaw to modify system files, install backdoors, modify user accounts, and perform other malicious activities that would otherwise require administrative access. The vulnerability is particularly dangerous because it operates at the system administration level where the program's elevated privileges are intended to provide legitimate system management capabilities. This flaw essentially undermines the security model of IRIX systems by allowing unauthorized privilege escalation through a path manipulation attack that bypasses normal security controls. The impact is significant for any organization relying on IRIX systems for critical operations, as it could lead to complete system compromise and data breaches.
Mitigation strategies for this vulnerability must address both the immediate security flaw and the broader system administration practices that contributed to its existence. The most effective immediate fix involves modifying the serial_ports program to use absolute paths when executing system utilities like ls, rather than relying on the user's PATH environment variable. This approach directly addresses the root cause by eliminating the trust relationship between the program and potentially compromised user paths. System administrators should also implement strict PATH environment variable controls and regularly audit system binaries for unauthorized modifications. The solution aligns with ATT&CK technique T1068 which describes privilege escalation through local exploitation of system vulnerabilities, and represents a fundamental security practice of using absolute paths in system administration tools. Organizations should also consider implementing privilege separation mechanisms and regular security auditing of system administration utilities to prevent similar vulnerabilities from emerging in other programs. Additionally, upgrading to newer versions of IRIX that address this specific flaw or applying vendor-provided patches would provide permanent resolution to this vulnerability.