CVE-2002-0762 in Linux
Summary
by MITRE
shadow package in SuSE 8.0 allows local users to destroy the /etc/passwd and /etc/shadow files or assign extra group privileges to some users by changing filesize limits before calling programs that modify the files.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 06/24/2024
The vulnerability described in CVE-2002-0762 represents a critical access control flaw within the shadow package implementation on SuSE 8.0 systems. This issue stems from improper handling of file size limits during the execution of programs that modify user authentication files. The shadow package is responsible for managing user account information and password data in Unix-like operating systems, making it a prime target for attackers seeking to manipulate system security controls. The vulnerability specifically affects the way the system handles file size constraints when programs attempt to modify the core authentication files that store user credentials and group memberships.
The technical flaw manifests when local users can manipulate the system's file size limits prior to executing programs that modify the /etc/passwd and /etc/shadow files. This manipulation allows attackers to either completely destroy these critical system files or to assign additional group privileges to existing users without proper authorization. The underlying issue lies in the insufficient validation of file size parameters and the lack of proper access controls during the modification process. When programs like useradd, usermod, or other user management utilities are executed, they rely on the system's file size limits to determine how much data they can write to these sensitive files. By altering these limits before execution, malicious users can bypass normal security mechanisms that would otherwise prevent unauthorized modifications.
The operational impact of this vulnerability extends beyond simple file corruption, as it enables attackers to fundamentally compromise system security through privilege escalation and authentication manipulation. Successful exploitation allows local users to gain unauthorized access to additional group memberships, potentially elevating their privileges to administrative levels. This type of vulnerability directly violates the principle of least privilege and can lead to complete system compromise when combined with other exploitation techniques. The attack vector is particularly dangerous because it requires minimal privileges initially and can be executed locally, making it difficult to detect through network monitoring alone. This vulnerability also demonstrates poor input validation and resource management practices that could affect other system components relying on similar file handling mechanisms.
The security implications of CVE-2002-0762 align with CWE-242, which addresses the use of potentially dangerous functions, and CWE-362, which covers concurrent execution without proper synchronization. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques under T1068 and credential access under T1003, as it allows attackers to modify user authentication data and gain elevated system access. Mitigation strategies should include implementing proper file size limit controls, enforcing strict access controls on authentication files, and ensuring that system utilities properly validate file parameters before execution. System administrators should also consider implementing mandatory access controls and monitoring for unusual file modification patterns. Regular security audits and updates to the shadow package should be prioritized to address such vulnerabilities, as they represent fundamental flaws in system security architecture that can be exploited to undermine the entire authentication infrastructure.