CVE-2005-3785 in IndeX
Summary
by MITRE
Second-order symlink vulnerability in eix-sync.in in Ebuild IndeX (eix) before 0.5.0_pre2 allows local users to overwrite arbitrary files via a symlink attack on the exi.X.sync temporary file, which is processed by the diff-eix program.
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Analysis
by VulDB Data Team • 06/12/2019
The vulnerability described in CVE-2005-3785 represents a sophisticated second-order symlink attack that exploits a critical flaw in the Ebuild IndeX (eix) tool version 0.5.0_pre2 and earlier. This vulnerability specifically targets the eix-sync.in script component within the eix package management system, creating a dangerous condition where local attackers can manipulate temporary file operations to achieve arbitrary file overwrites. The attack leverages the improper handling of temporary files during the synchronization process, particularly focusing on the exi.X.sync temporary file that is subsequently processed by the diff-eix program. The second-order nature of this vulnerability means that the malicious symlink is not directly used in the initial attack but rather becomes active during a later stage of the process, making it particularly insidious and difficult to detect through simple static analysis.
The technical implementation of this vulnerability stems from inadequate temporary file handling and insufficient validation of symbolic link references within the eix synchronization framework. When the eix-sync.in script executes, it creates or processes temporary files without proper security checks to verify that these files are not symbolic links pointing to sensitive system locations. The flaw occurs because the system does not validate whether the temporary file exi.X.sync contains a symbolic link that could be manipulated by an attacker. This vulnerability falls under the category of improper file handling and symbolic link manipulation, which aligns with CWE-377 and CWE-378 classifications related to insecure temporary file creation and improper handling of symbolic links. The attack requires an attacker to have local access to the system and the ability to place a malicious symlink in a location where it will be processed by the vulnerable eix tool, but once executed, it can lead to privilege escalation or data corruption.
The operational impact of this vulnerability extends beyond simple file overwrites and can potentially enable more severe security consequences within affected systems. When exploited, the vulnerability allows attackers to replace critical system files, configuration files, or even executables with malicious content, effectively compromising the integrity of the entire package management system. The affected environment typically includes systems using the eix tool for managing Gentoo Linux packages, where the vulnerability can be leveraged to gain elevated privileges or disrupt normal system operations. The attack can be particularly damaging in environments where eix is used with elevated privileges or where automated synchronization processes run with higher permissions than typical user accounts. This vulnerability directly impacts the CIA triad, specifically compromising data integrity and potentially availability when critical system files are overwritten or corrupted.
Mitigation strategies for this vulnerability must address both the immediate technical flaw and the broader security practices surrounding temporary file handling and symbolic link management. The primary remediation involves upgrading to eix version 0.5.0_pre2 or later, where the developers have implemented proper validation of temporary file operations and symbolic link detection. System administrators should also implement additional security controls such as ensuring that temporary directories are properly secured with appropriate permissions, disabling unnecessary symbolic link resolution in package management tools, and regularly auditing system files for unauthorized modifications. Organizations should also consider implementing principle of least privilege practices where package synchronization operations run with minimal necessary privileges. The vulnerability demonstrates the importance of proper temporary file management as outlined in the OWASP Top Ten security practices and aligns with ATT&CK technique T1059.007 for executing malicious code through package managers, making it a critical concern for system administrators and security teams managing Gentoo-based environments.