CVE-2014-0243 in Check_MK
Summary
by MITRE
Check_MK through 1.2.5i2p1 allows local users to read arbitrary files via a symlink attack to a file in /var/lib/check_mk_agent/job.
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Analysis
by VulDB Data Team • 02/27/2025
The vulnerability identified as CVE-2014-0243 affects Check_MK versions through 1.2.5i2p1 and represents a critical local privilege escalation issue stemming from insecure file handling practices. This flaw enables malicious local users to access arbitrary files on the system through a carefully crafted symbolic link attack targeting a specific directory path. The vulnerability resides within the Check_MK agent component that processes files in the /var/lib/check_mk_agent/job directory, where improper file access controls and insecure temporary file handling create an exploitable condition. The attack vector specifically leverages the manipulation of symbolic links to bypass normal file access restrictions and gain unauthorized read access to sensitive system files.
The technical implementation of this vulnerability demonstrates a classic race condition and insecure file handling pattern that falls under CWE-377, which addresses insecure temporary file usage, and CWE-22, which covers improper limitation of a pathname to a restricted directory. The flaw occurs because the Check_MK agent does not properly validate or sanitize symbolic links before processing them, allowing attackers to create malicious symlinks that point to protected files. When the agent processes these symlinks, it follows the symbolic link and reads the target file content, effectively bypassing normal access controls. This type of vulnerability is particularly dangerous in monitoring environments where agent processes often run with elevated privileges to collect system information.
The operational impact of CVE-2014-0243 extends beyond simple information disclosure, as it can enable attackers to extract sensitive configuration data, system credentials, or other confidential information stored in files accessible through the compromised agent. Attackers can exploit this vulnerability to gather intelligence about system configuration, installed packages, network settings, and potentially access authentication tokens or credentials stored in files within the monitored system. The vulnerability affects systems where Check_MK agents are deployed with local administrative privileges, making it particularly concerning in enterprise environments where monitoring agents often require elevated access to perform their functions. This weakness can be exploited by attackers who have gained low-privilege access to the system, potentially escalating their privileges to access sensitive system resources.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Check_MK versions to the latest releases that address the symbolic link handling issues. System administrators should implement proper file access controls and ensure that the /var/lib/check_mk_agent/job directory is properly secured with appropriate permissions. The recommended approach includes verifying that symbolic links are not followed during file processing and implementing proper input validation for all file operations. Organizations should also consider implementing file integrity monitoring solutions to detect unauthorized symbolic link creation and establish regular security audits of monitoring agent configurations. Additionally, following the principle of least privilege and ensuring that monitoring agents run with minimal required permissions can significantly reduce the impact of such vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1078 for valid accounts, as it can be exploited through legitimate system accounts to gain unauthorized access to sensitive data through compromised monitoring agents.