CVE-2015-0794 in openSUSE
Summary
by MITRE
modules.d/90crypt/module-setup.sh in the dracut package before 037-17.30.1 in openSUSE 13.2 allows local users to have unspecified impact via a symlink attack on /tmp/dracut_block_uuid.map.
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Analysis
by VulDB Data Team • 12/02/2024
The vulnerability identified as CVE-2015-0794 resides within the dracut package's module-setup.sh script located in the modules.d/90crypt directory. This issue affects openSUSE 13.2 systems where the dracut package version is prior to 037-17.30.1. The flaw represents a classic symlink attack vector that exploits insecure temporary file handling during the system's boot process initialization. The attack occurs when the module-setup.sh script creates or modifies files in the /tmp directory without proper validation of symbolic links, creating a path where malicious actors can manipulate the intended file operations.
The technical implementation of this vulnerability stems from the insecure creation of temporary files in the /tmp directory without appropriate access controls or atomic operations. When dracut processes cryptographic modules during system initialization, it generates temporary files including /tmp/dracut_block_uuid.map to store block device identification information. The module-setup.sh script fails to verify whether these temporary files are legitimate or symbolic links that could be manipulated by unauthorized users. This insecure practice creates a race condition scenario where an attacker can establish a symbolic link pointing to a privileged file before the legitimate file creation occurs, thereby allowing arbitrary file access or modification.
The operational impact of this vulnerability extends beyond simple privilege escalation as it affects the system's boot process integrity and overall security posture. An attacker with local access can potentially manipulate the cryptographic module setup process to gain unauthorized access to system resources or modify critical boot-time configurations. This vulnerability particularly impacts systems where dracut is used for generating initramfs images, as it can compromise the integrity of the boot process itself. The unspecified impact mentioned in the CVE description suggests that the consequences could range from information disclosure to complete system compromise depending on how the symbolic link manipulation affects the system's cryptographic operations and file permissions.
Mitigation strategies for this vulnerability require immediate patching of the dracut package to version 037-17.30.1 or later, which addresses the insecure temporary file handling by implementing proper symlink validation and atomic file creation procedures. System administrators should also implement additional security measures such as verifying the integrity of temporary directories and ensuring proper file permissions are maintained throughout the boot process. The vulnerability aligns with CWE-377: Insecure Temporary File and CWE-378: Poorly Made Temporary Files, both of which are categorized under the broader category of insecure file handling practices. From an attack perspective, this vulnerability maps to ATT&CK technique T1059.007 for executing commands through shell scripts and potentially T1547.001 for privilege escalation through system initialization processes. Organizations should conduct comprehensive vulnerability assessments to ensure all systems running affected versions of dracut are updated and that proper monitoring is in place to detect potential exploitation attempts targeting the /tmp directory and related temporary file operations.