CVE-2023-0634 in shadow
Summary
by MITRE • 02/03/2023
An uncontrolled process operation was found in the newgrp command provided by the shadow-utils package. This issue could cause the execution of arbitrary code provided by a user when running the newgrp command.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2023-0634 represents a critical security flaw within the shadow-utils package that affects the newgrp command functionality. This issue manifests as an uncontrolled process operation that can be exploited to execute arbitrary code when the newgrp command is invoked by users. The vulnerability resides in how the system handles group membership changes and process execution contexts when users attempt to switch to new groups through the newgrp utility.
The technical implementation of this vulnerability stems from improper handling of process control mechanisms within the newgrp command. When a user executes newgrp to switch to a different group, the command should properly validate and sanitize all input parameters before proceeding with the group transition process. However, the flaw allows malicious input to influence the command's execution flow, potentially enabling attackers to inject and execute arbitrary code within the context of the new group membership. This represents a classic privilege escalation vector that can be leveraged by attackers to gain elevated system privileges.
From an operational impact perspective, this vulnerability poses significant risks to system security and integrity. The newgrp command is commonly used in Unix-like systems for group membership management, making this vulnerability exploitable in environments where users have legitimate access to execute this command. Attackers could potentially exploit this flaw to execute malicious code with the privileges of the target group, or even escalate to root privileges depending on system configuration and access controls. The vulnerability's impact extends across various system components as it affects the core group management functionality that underpins many security policies and access control mechanisms.
The vulnerability aligns with CWE-78 and CWE-787 categories from the Common Weakness Enumeration catalog, specifically addressing issues related to command injection and improper input validation. This flaw can be mapped to several ATT&CK techniques including T1068 for privilege escalation and T1203 for exploitation of software vulnerabilities. The attack surface is particularly concerning as it involves a fundamental system utility that is part of standard Unix and Linux distributions, making it widely accessible across different system configurations.
Mitigation strategies for CVE-2023-0634 should prioritize immediate patching of the shadow-utils package to address the underlying process control implementation. System administrators should also implement strict access controls on the newgrp command, potentially restricting its execution through sudo rules or file permissions. Additional defensive measures include monitoring for suspicious newgrp command usage patterns and implementing proper input validation mechanisms within custom scripts that may interact with group management functions. Regular security audits of system utilities and privilege escalation mechanisms should be conducted to identify similar vulnerabilities that could compromise system integrity and user security.