CVE-2002-2221 in chetcpasswd
Summary
by MITRE
Untrusted search path vulnerability in Pedro Lineu Orso chetcpasswd 2.4.1 and earlier allows local users to gain privileges via a modified PATH that references a malicious cp binary. NOTE: this issue might overlap CVE-2006-6639.
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Analysis
by VulDB Data Team • 06/11/2018
The vulnerability identified as CVE-2002-2221 represents a classic untrusted search path issue affecting Pedro Lineu Orso chetcpasswd version 2.4.1 and earlier. This type of vulnerability falls under the broader category of CWE-426 Untrusted Search Path, which occurs when a program searches for executable files or libraries in directories that can be manipulated by untrusted users. The specific flaw manifests in the chetcpasswd utility's improper handling of the PATH environment variable during execution, creating a privilege escalation opportunity for local attackers. The vulnerability is particularly concerning because it allows attackers to manipulate the execution flow of a system utility that typically requires elevated privileges to modify password files.
The technical exploitation of this vulnerability relies on the attacker's ability to manipulate the PATH environment variable in a way that causes the system to execute a malicious version of the cp binary instead of the legitimate system binary. When chetcpasswd executes commands that require copying files, it does not explicitly specify the full path to the cp utility, instead relying on the system's PATH resolution mechanism. This creates an opportunity for an attacker who has write access to a directory in the PATH to place a malicious cp binary that appears to be the legitimate system utility. The malicious binary can then be crafted to perform unauthorized actions while maintaining the appearance of legitimate system operation, effectively allowing privilege escalation from a regular user to a privileged account.
The operational impact of CVE-2002-2221 extends beyond simple privilege escalation, as it represents a fundamental flaw in how the chetcpasswd utility handles system calls and environment variables. This vulnerability can be leveraged to modify system password files, potentially allowing attackers to gain persistent access to systems or escalate their privileges to root level. The issue's classification under the ATT&CK framework would likely fall under T1068 Privilege Escalation and T1548.1 Account Manipulation, as attackers can manipulate system accounts through the compromised utility. The vulnerability's exploitation is particularly dangerous because it requires minimal privileges to execute and can be automated, making it a significant concern for system administrators managing multiple user accounts.
Mitigation strategies for CVE-2002-2221 should focus on implementing proper path validation and explicit binary execution. System administrators should ensure that all system utilities are invoked with explicit full paths rather than relying on PATH resolution. This approach aligns with security best practices outlined in the CWE guidelines for preventing untrusted search path vulnerabilities. The recommended solution involves modifying the chetcpasswd utility to hardcode absolute paths to all required system binaries, eliminating the possibility of PATH manipulation attacks. Additionally, implementing proper access controls and privilege separation can reduce the attack surface, as can regular security audits to identify and remediate similar issues in other system utilities. The vulnerability also highlights the importance of keeping software updated, as newer versions of chetcpasswd would have addressed this issue through proper path handling mechanisms.