CVE-2005-4889 in RPM
Summary
by MITRE
lib/fsm.c in RPM before 4.4.3 does not properly reset the metadata of an executable file during deletion of the file in an RPM package removal, which might allow local users to gain privileges by creating a hard link to a vulnerable (1) setuid or (2) setgid file, a related issue to CVE-2010-2059.
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Analysis
by VulDB Data Team • 09/14/2021
The vulnerability described in CVE-2005-4889 resides within the RPM package management system's file system management component, specifically in the lib/fsm.c file. This flaw represents a critical security issue that affects RPM versions prior to 4.4.3, creating a persistent security risk through improper metadata handling during package removal operations. The vulnerability stems from the failure to properly reset file metadata when executable files are deleted from packages, leaving behind remnants that can be exploited by malicious actors.
The technical implementation of this vulnerability involves the RPM package manager's handling of setuid and setgid files during package removal processes. When an RPM package containing setuid or setgid executables is removed, the system fails to completely purge the metadata associated with these privileged files. This incomplete cleanup process leaves behind file system attributes that can be manipulated by local users, creating a potential privilege escalation vector. The flaw specifically affects how RPM manages hard links to vulnerable files, allowing attackers to exploit the lingering metadata to gain elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it creates a persistent backdoor mechanism within systems using affected RPM versions. Local users can leverage this flaw to maintain elevated access even after package removal, effectively bypassing the normal security controls that should be enforced when packages are uninstalled. The vulnerability is particularly concerning because it operates at the package management layer, where system administrators expect complete removal of security-sensitive components. This issue represents a significant deviation from expected security practices and can undermine the integrity of entire system security frameworks.
This vulnerability aligns with CWE-276, which addresses improper file permissions and access control, and relates to the broader category of privilege escalation flaws. The attack vector follows patterns consistent with ATT&CK technique T1068, which involves exploiting weaknesses in system processes to gain elevated privileges. The flaw demonstrates a critical failure in the principle of least privilege, as it allows users to maintain access to system resources that should be completely removed upon package uninstallation. The vulnerability's relationship to CVE-2010-2059 indicates a pattern of similar metadata handling issues within the RPM package management system, suggesting systemic problems in how the software handles privileged file operations.
Mitigation strategies for CVE-2005-4889 require immediate system updates to RPM versions 4.4.3 or later, which contain the necessary patches to properly reset file metadata during package removal. System administrators should conduct comprehensive audits of installed packages to identify any remaining vulnerable setuid/setgid files that might have been affected by this issue. Additionally, implementing proper monitoring of file system changes and access patterns can help detect exploitation attempts. Organizations should also review their package management workflows to ensure that privileged files are properly handled during installation and removal operations, and consider implementing additional security controls such as file integrity monitoring to detect unauthorized modifications to critical system files.