CVE-2015-0267 in Red Hat
Summary
by MITRE
The Red Hat module-setup.sh script for kexec-tools, as distributed in the kexec-tools before 2.0.7-19 packages in Red Hat Enterprise Linux, allows local users to write to arbitrary files via a symlink attack on a temporary file.
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Analysis
by VulDB Data Team • 12/02/2024
The vulnerability identified as CVE-2015-0267 represents a critical security flaw in the Red Hat kexec-tools package that affects systems running Red Hat Enterprise Linux. This issue specifically targets the module-setup.sh script which is responsible for managing kernel module setup operations. The vulnerability stems from improper handling of temporary files during the execution of the kexec-tools module setup process, creating a predictable race condition that malicious local users can exploit to gain unauthorized file system access.
The technical implementation of this vulnerability follows a classic symlink attack pattern where an attacker manipulates symbolic links to redirect file operations to unintended destinations. The module-setup.sh script creates temporary files without proper security checks, allowing local users to establish symbolic links that point to sensitive system files or directories. When the script subsequently writes to these temporary files, the write operations are actually directed to the target files specified by the attacker-controlled symlinks rather than the intended temporary locations. This flaw is categorized under CWE-377 as insecure temporary file creation and falls under the broader category of CWE-367 which addresses improper neutralization of special elements used in file paths.
The operational impact of CVE-2015-0267 is significant for systems running vulnerable versions of kexec-tools, as it provides local attackers with the ability to modify arbitrary files on the system. This can lead to privilege escalation, system compromise, or data corruption depending on the target files that are overwritten. The vulnerability is particularly dangerous because it requires minimal privileges to exploit, making it accessible to any local user who can execute the kexec-tools module setup process. Attackers can leverage this to overwrite critical system files, modify configuration data, or establish persistent access mechanisms within the compromised system.
Mitigation strategies for CVE-2015-0267 involve immediate patching of the kexec-tools package to version 2.0.7-19 or later, which includes proper temporary file handling mechanisms that prevent symlink attacks. System administrators should also implement additional security measures such as restricting execution permissions on the module-setup.sh script and monitoring for suspicious file system activities around temporary file creation. The vulnerability demonstrates the importance of proper file system security practices and aligns with ATT&CK technique T1059.001 for command and scripting interpreter execution, as well as T1068 for exploit for privilege escalation. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized modifications to critical system files that may result from exploitation of this vulnerability.