CVE-1999-1390 in Linux
Summary
by MITRE
suidexec in suidmanager 0.18 on Debian 2.0 allows local users to gain root privileges by specifying a malicious program on the command line.
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Analysis
by VulDB Data Team • 09/21/2024
The vulnerability described in CVE-1999-1390 represents a critical privilege escalation flaw within the suidmanager package version 0.18 running on Debian 2.0 systems. This issue stems from improper handling of command line arguments in the suidexec utility, which is designed to execute programs with elevated privileges. The vulnerability operates under the principle of insecure parameter handling where the system fails to properly validate or sanitize user-supplied input before executing commands with root privileges. This flaw directly violates fundamental security principles of input validation and privilege separation that are essential for maintaining system integrity.
The technical implementation of this vulnerability occurs when a local user can manipulate the command line arguments passed to suidexec, allowing them to specify arbitrary programs that will be executed with root permissions. The flaw exists because the suidmanager package does not properly implement proper argument sanitization or validation mechanisms before invoking the target program. This creates a path where user-controlled input can be directly interpreted and executed without proper security checks, effectively bypassing the intended privilege boundaries. The vulnerability is classified under CWE-78 as a failure to sanitize system inputs, specifically command injection, which is a well-documented weakness in Unix-like systems where command execution is involved.
The operational impact of this vulnerability is severe as it provides local users with complete root access to affected systems. Once exploited, attackers can execute arbitrary code with the highest system privileges, potentially leading to complete system compromise, data exfiltration, or persistent backdoor installation. The attack vector is relatively simple since it only requires local access to the system, making it particularly dangerous in multi-user environments where users might not have legitimate reasons to require root privileges. This vulnerability undermines the core security model of Unix-like systems where privilege separation is fundamental to preventing unauthorized system access. The exploitation aligns with ATT&CK technique T1068 which involves the use of legitimate credentials and system tools to escalate privileges, making this a classic example of how insecure command execution can be weaponized.
Mitigation strategies for this vulnerability involve immediate patching of the suidmanager package to version 0.19 or later, which includes proper input validation and argument sanitization. System administrators should also implement proper privilege separation mechanisms and avoid using unnecessary suid binaries in modern system configurations. The principle of least privilege should be enforced by removing or restricting suid permissions on unnecessary programs. Additionally, monitoring for suspicious command execution patterns and implementing proper audit logging can help detect exploitation attempts. Organizations should consider migrating away from legacy suid-based privilege escalation mechanisms toward more secure alternatives such as sudo with proper configuration or container-based privilege management. The vulnerability demonstrates the critical importance of input validation in security-sensitive code and the potential catastrophic consequences when such validation is absent or inadequate in privilege escalation components.