CVE-2012-0948 in Update-manager-core
Summary
by MITRE
DistUpgrade/DistUpgradeMain.py in Update Manager, as used by Ubuntu 12.04 LTS, 11.10, and 11.04, uses weak permissions for (1) apt-clone_system_state.tar.gz and (2) system_state.tar.gz, which allows local users to obtain repository credentials.
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Analysis
by VulDB Data Team • 12/03/2021
The vulnerability identified as CVE-2012-0948 resides within the Update Manager component of Ubuntu operating systems, specifically affecting versions 11.04, 11.10, and 12.04 LTS. This issue manifests in the DistUpgrade/DistUpgradeMain.py script which handles system upgrade processes. The flaw stems from improper file permission handling during the upgrade procedure where temporary archive files are created with insufficient access controls. These files contain sensitive system information including repository credentials that are essential for package management operations.
The technical implementation of this vulnerability involves the creation of two specific temporary files named apt-clone_system_state.tar.gz and system_state.tar.gz during the distribution upgrade process. These files are generated with weak file permissions that allow any local user on the system to read their contents. The underlying flaw aligns with CWE-732, which describes improper permission assignment for critical resources, and represents a classic case of inadequate access control mechanisms. The Update Manager script fails to properly secure these temporary files, creating a privilege escalation vector that undermines the system's security posture.
From an operational perspective, this vulnerability presents a significant risk to system security as local users can exploit it to extract repository credentials stored within the temporary archive files. These credentials typically contain authentication information for package repositories including usernames, passwords, or API tokens that grant access to software repositories. The impact extends beyond simple information disclosure since these credentials can be leveraged by malicious actors to gain unauthorized access to package repositories, potentially leading to supply chain attacks or unauthorized package installations. Attackers could use the obtained credentials to modify package sources, inject malicious software, or redirect system updates to compromised repositories.
The attack surface for this vulnerability is considerable given that it affects multiple Ubuntu versions and operates during routine system maintenance activities. Since the issue occurs during the standard upgrade process, it is likely to be triggered regularly, providing attackers with multiple opportunities to exploit the weakness. This vulnerability also aligns with ATT&CK technique T1552.001, which covers "Credentials In Files," and demonstrates how legitimate system processes can inadvertently create security weaknesses. The persistence of this vulnerability across several Ubuntu releases indicates a systemic issue in the implementation of file access controls within the Update Manager framework.
Mitigation strategies for CVE-2012-0948 should prioritize immediate patching of affected Ubuntu systems to the latest available security updates from Canonical. System administrators should implement proper file permission controls on temporary directories and ensure that sensitive files are created with restrictive permissions immediately after generation. The recommended approach includes setting appropriate umask values and implementing secure temporary file creation practices. Additionally, organizations should consider monitoring for unauthorized access to temporary directories and implementing automated security scanning to detect similar permission issues in other system components. The vulnerability serves as a reminder of the importance of secure coding practices and the need for comprehensive security reviews of system maintenance tools.