CVE-2014-5284 in OSSEC
Summary
by MITRE
host-deny.sh in OSSEC before 2.8.1 writes to temporary files with predictable filenames without verifying ownership, which allows local users to modify access restrictions in hosts.deny and gain root privileges by creating the temporary files before automatic IP blocking is performed.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/26/2024
The vulnerability described in CVE-2014-5284 represents a critical privilege escalation flaw within the OSSEC security solution, specifically affecting versions prior to 2.8.1. This issue resides in the host-deny.sh script which is responsible for managing IP address blocking through the hosts.deny file, a fundamental component of Unix-based systems for controlling access restrictions. The vulnerability stems from improper handling of temporary file creation processes that lack sufficient security measures to prevent unauthorized modification by local users.
The technical flaw manifests in the predictable naming convention used for temporary files within the host-deny.sh script. When OSSEC automatically performs IP blocking operations, it creates temporary files with deterministic names that can be easily anticipated by local attackers. This predictability, combined with the absence of ownership verification mechanisms, creates a race condition scenario where malicious users can pre-create these temporary files with malicious content before the legitimate script execution occurs. The script operates under root privileges during the automatic IP blocking process, making the potential for privilege escalation particularly severe when attackers can manipulate the temporary file contents that will be processed with elevated permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete control over the host access restrictions mechanism. By creating malicious temporary files that will be processed by the root-privileged host-deny.sh script, attackers can effectively modify the hosts.deny file to allow unauthorized access to the system while simultaneously blocking legitimate access attempts. This creates a sophisticated attack vector that can be used to establish persistent access, bypass security controls, and potentially compromise the entire system infrastructure. The vulnerability is particularly dangerous in environments where OSSEC is deployed with default configurations and where local users have access to the system.
The attack pattern for this vulnerability aligns with common privilege escalation techniques documented in the ATT&CK framework under privilege escalation tactics, specifically leveraging the use of temporary files and race conditions. From a CWE perspective, this vulnerability maps to CWE-362, which describes race conditions that can lead to privilege escalation through improper temporary file handling. The flaw also demonstrates characteristics of CWE-276, which addresses improper file permissions and access control. Security practitioners should note that this vulnerability is particularly relevant in multi-user environments where local privilege escalation is a significant concern, and where the use of automated security tools like OSSEC may inadvertently create additional attack surfaces.
Mitigation strategies for CVE-2014-5284 require immediate patching of OSSEC installations to version 2.8.1 or later, where the temporary file handling has been corrected to use secure naming conventions and proper ownership verification. Organizations should also implement additional security measures such as verifying file ownership and permissions before processing temporary files, using secure temporary file creation methods that include randomization, and monitoring for unauthorized modifications to security-related files. System administrators should consider implementing mandatory access controls and file integrity monitoring to detect potential exploitation attempts, while also reviewing the overall security posture of their OSSEC implementations to prevent similar vulnerabilities in other components of the security infrastructure.