CVE-2004-2778 in Linux
Summary
by MITRE
Ebuild in Gentoo may change directory and file permissions depending on the order of installed packages, which allows local users to read or write to restricted directories or execute restricted commands via navigating to the affected directories, or executing the affected commands.
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Analysis
by VulDB Data Team • 10/20/2019
This vulnerability exists within the package management system of Gentoo Linux where ebuild scripts can manipulate directory and file permissions during package installation processes. The core issue stems from improper handling of permission changes that occur when packages are installed in specific orders, creating a race condition scenario where the security context of directories and files becomes unpredictable. When packages are installed sequentially, the ebuild mechanisms may inadvertently alter access controls in ways that were not intended during the package build process, leading to potential privilege escalation and unauthorized access to restricted system resources.
The technical flaw manifests through the improper execution of permission-setting commands within ebuild scripts that do not adequately account for the existing security context of target directories and files. This vulnerability falls under the category of improper access control as defined by CWE-284, where the system fails to properly enforce access restrictions on system resources. The vulnerability is particularly concerning because it allows local users to manipulate the filesystem permissions in such a way that they can gain access to restricted directories or execute commands that should normally be protected from their user privileges. The issue is exacerbated by the fact that the vulnerability's impact depends on the installation order of packages, making it difficult to predict and prevent.
The operational impact of this vulnerability extends beyond simple permission mismanagement to potentially enable local privilege escalation and arbitrary code execution. Attackers can exploit this weakness by carefully selecting the order in which packages are installed to manipulate the filesystem state in their favor. This creates a persistent security risk where the system's integrity is compromised through legitimate package management operations. The vulnerability is particularly dangerous in multi-user environments where local users might attempt to exploit this weakness to gain elevated privileges or access sensitive system information. The attack surface is broad as it affects any package installation process that involves directory permission changes.
Mitigation strategies should focus on implementing proper validation of permission changes within ebuild scripts and ensuring that package installation order does not affect the security context of system resources. System administrators should regularly audit package installations and monitor for unusual permission changes that might indicate exploitation attempts. The implementation of mandatory access controls and regular security scanning of installed packages can help detect and prevent exploitation of this vulnerability. Additionally, upgrading to newer versions of Gentoo's package management system where this issue has been addressed through proper permission handling mechanisms is essential. Organizations should also consider implementing least privilege principles and regular system integrity checks to minimize the potential impact of such vulnerabilities. This vulnerability demonstrates the importance of proper access control implementation in package management systems and aligns with ATT&CK techniques related to privilege escalation through local exploitation methods.