Overview
CVE-2025-49642 describes a security vulnerability affecting AIX Zabbix Agent builds. This vulnerability allows local users with write access to the /home/cecuser directory to potentially hijack library loading, leading to arbitrary code execution within the context of the Zabbix Agent. This happens due to insecure default configurations in certain Zabbix Agent builds on AIX.
Technical Details
The vulnerability stems from how the Zabbix Agent on AIX handles library loading. If a user has write access to the /home/cecuser directory, they can place malicious shared libraries (e.g., .so files) in that directory. When the Zabbix Agent starts or loads certain components, it may search for and load libraries from the /home/cecuser directory if it’s inadvertently included in the library search path, or if the agent attempts to load libraries relative to the current directory of the cecuser home folder. This can allow an attacker to execute arbitrary code with the privileges of the Zabbix Agent process.
The specific flaw relates to the Zabbix Agent incorrectly resolving library dependencies, inadvertently including potentially writable directories (like the specified user’s home directory) in its library search path.
CVSS Analysis
At the time of publication (2025-12-01), a CVSS score is not available for CVE-2025-49642. However, given the potential for arbitrary code execution, a CVSS score in the 7.0-9.0 range (High) is likely upon evaluation, assuming successful exploitation results in code execution under the agent’s security context. The lack of user interaction required and local attack vector contribute to a potentially high score.
Severity: N/A
CVSS Score: N/A
Possible Impact
Successful exploitation of this vulnerability could lead to the following consequences:
- Arbitrary Code Execution: An attacker could execute arbitrary code on the affected AIX system with the privileges of the Zabbix Agent, potentially leading to complete system compromise.
- Data Breach: The attacker could gain access to sensitive data monitored by the Zabbix Agent, such as system logs, performance metrics, and configuration information.
- System Instability: Malicious code execution could cause the Zabbix Agent or the entire system to crash.
- Lateral Movement: An attacker could use the compromised system as a springboard to attack other systems on the network.
Mitigation or Patch Steps
To mitigate this vulnerability, the following steps should be taken:
- Upgrade Zabbix Agent: Upgrade to the latest version of the Zabbix Agent that includes a fix for ZBX-27283, as this likely addresses the library loading issue. Check the Zabbix release notes for confirmation.
- Restrict Write Access: Ensure that only trusted users have write access to the
/home/cecuserdirectory. Review and enforce strict file permissions. - Verify Library Search Path: Carefully examine the library search path configuration for the Zabbix Agent. Ensure that untrusted directories, especially user home directories, are not included in the search path. Use tools like
lddon the Zabbix Agent executable to check which libraries are loaded and from where. - Consider a Separate User: Instead of running the agent under a user whose home directory is easily accessible or modifiable, consider creating a dedicated service account with minimal privileges and a restricted home directory.
