CVE-2001-1175 in util-linux
Summary
by MITRE
vipw in the util-linux package before 2.10 causes /etc/shadow to be world-readable in some cases, which would make it easier for local users to perform brute force password guessing.
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Analysis
by VulDB Data Team • 05/30/2017
The vulnerability identified as CVE-2001-1175 affects the vipw utility within the util-linux package version 2.10 and earlier. This flaw represents a critical security issue that undermines the integrity of system authentication mechanisms by creating unintended access permissions to the sensitive /etc/shadow file. The vipw command serves as a privileged utility for modifying user account information, particularly designed to provide controlled access to the shadow password file while maintaining appropriate security controls.
The technical implementation flaw stems from improper permission handling within the vipw utility's file creation and modification processes. When vipw executes, it temporarily creates a working copy of the /etc/shadow file to facilitate user modifications. In vulnerable versions, this temporary file is created with overly permissive permissions, specifically allowing world-read access. This occurs because the utility fails to properly set restrictive file permissions during the temporary file creation phase, leaving the shadow file contents exposed to any local user on the system.
The operational impact of this vulnerability creates significant risk for system security and authentication integrity. Local users who can access the world-readable shadow file gain access to encrypted password hashes and other account information that would normally be restricted. This exposure enables attackers to perform offline brute force password guessing attacks against the captured hash values, significantly reducing the time and computational resources required to compromise user accounts. The vulnerability essentially provides a backdoor pathway for password cracking attempts that would otherwise require more sophisticated attack vectors or elevated privileges.
The security implications extend beyond simple password exposure, as this vulnerability aligns with multiple ATT&CK framework techniques including privilege escalation and credential access. It specifically relates to CWE-732: Incorrect Permission Assignment for Critical Resource, which addresses improper access control mechanisms that allow unauthorized users to modify or access sensitive system resources. The flaw demonstrates poor privilege separation and inadequate file permission management within the system utilities, creating a persistent security weakness that affects all systems running vulnerable versions of util-linux.
Mitigation strategies should focus on immediate package updates to version 2.10 or later where this vulnerability has been resolved. System administrators must verify that all systems have been patched and that the updated vipw utility properly implements restrictive file permissions during temporary file operations. Additional measures include implementing proper file permission monitoring, conducting regular security audits of system utilities, and ensuring that privilege escalation mechanisms maintain appropriate access controls. Organizations should also consider implementing account lockout policies and stronger password requirements to reduce the effectiveness of brute force attacks even when the vulnerability exists. The remediation process must include verification that the vipw utility correctly handles temporary file creation and that no other system utilities exhibit similar permission handling flaws.