CVE-2011-0461 in openSUSE
Summary
by MITRE
/etc/init.d/boot.localfs in the aaa_base package before 11.2-43.48.1 in SUSE openSUSE 11.2, and before 11.3-8.7.1 in openSUSE 11.3, allows local users to overwrite arbitrary files via a symlink attack on /dev/shm/mtab.
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Analysis
by VulDB Data Team • 10/21/2021
The vulnerability described in CVE-2011-0461 represents a critical privilege escalation and file overwrite issue within the SUSE openSUSE operating system distribution. This flaw exists in the aaa_base package, which is fundamental to system initialization and user management processes. The vulnerability specifically targets the /etc/init.d/boot.localfs script that handles local filesystem initialization during system boot. The issue arises from improper handling of symbolic links in a temporary directory, creating a window of opportunity for local attackers to manipulate system files through a carefully crafted symlink attack.
The technical implementation of this vulnerability exploits a race condition in the boot.localfs script where the system creates or modifies files in the /dev/shm/mtab location without proper validation of symbolic link integrity. This directory is part of the shared memory filesystem that provides temporary storage during system operation. The attacker can create a malicious symbolic link at /dev/shm/mtab that points to any file on the system, then trigger the vulnerable script execution to overwrite arbitrary files with malicious content. This type of vulnerability falls under the category of CWE-377: Insecure Temporary File and CWE-367: Time-of-Check to Time-of-Use, where the system checks for file existence or permissions at one point in time but operates on different file content or permissions at another point.
The operational impact of this vulnerability is significant as it allows local users with minimal privileges to gain elevated access and modify critical system files. An attacker could potentially overwrite configuration files, binary executables, or system libraries to achieve persistent access or cause system instability. The vulnerability affects specific versions of SUSE openSUSE 11.2 and 11.3, making it particularly dangerous for systems running these outdated releases. This flaw essentially provides a path for privilege escalation from regular user to root level access, undermining the fundamental security model of the operating system. The attack vector is particularly concerning because it occurs during system boot initialization, when the system is in a vulnerable state and the attacker can leverage the timing of file creation operations.
Mitigation strategies for this vulnerability involve immediate patching of the affected aaa_base package to versions 11.2-43.48.1 and 11.3-8.7.1 respectively. System administrators should also implement proper file system permissions and validate symbolic link integrity before file operations. The remediation aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, where attackers exploit weaknesses in system processes to gain elevated privileges. Additional defensive measures include monitoring for unauthorized file modifications in critical system directories, implementing proper access controls on temporary directories, and conducting regular security audits of system initialization scripts. Organizations should also consider implementing automated patch management systems to prevent similar vulnerabilities from persisting in their environments. The vulnerability highlights the importance of proper file system security practices and the need for careful validation of file operations in system initialization processes.