CVE-2025-27237 in Zabbix
Summary
by MITRE • 10/03/2025
In Zabbix Agent and Agent 2 on Windows, the OpenSSL configuration file is loaded from a path writable by low-privileged users, allowing malicious modification and potential local privilege escalation by injecting a DLL.
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Analysis
by VulDB Data Team • 10/06/2025
The vulnerability identified as CVE-2025-27237 represents a critical security flaw in Zabbix Agent and Agent 2 versions running on Windows operating systems. This issue stems from improper handling of OpenSSL configuration files within the Zabbix agent implementation, creating a pathway for privilege escalation attacks that directly impacts system security posture. The flaw specifically affects the Windows deployment of Zabbix monitoring agents, which are widely used for infrastructure monitoring and network management across enterprise environments.
The technical root cause of this vulnerability lies in the insecure loading mechanism of OpenSSL configuration files. The system loads these configuration files from paths that are writable by low-privileged user accounts, creating a dangerous condition where malicious actors can modify the configuration files to inject malicious code. This design flaw violates fundamental security principles of least privilege and secure file handling, as it allows users with minimal system access to manipulate critical components that are typically restricted to administrators or system processes. The vulnerability manifests when the Zabbix agent processes OpenSSL configuration, which then loads malicious DLLs from these writable locations, effectively enabling code execution with elevated privileges.
From an operational perspective, this vulnerability presents a significant risk to organizations using Zabbix for system monitoring, as it allows attackers to escalate privileges from standard user accounts to system-level access. The impact extends beyond simple privilege escalation, potentially enabling full system compromise and unauthorized access to sensitive data. Attackers can leverage this vulnerability to establish persistent access, exfiltrate data, or deploy additional malicious software within the compromised environment. The attack vector is particularly concerning because it requires minimal privileges to exploit, making it accessible to attackers who may have gained initial access through other means such as phishing or credential theft. This vulnerability directly relates to CWE-276, which addresses improper privileges, and CWE-427, which deals with uncontrolled search path, as the insecure path handling creates opportunities for code injection through configuration files.
The exploitation of this vulnerability follows a systematic approach where attackers first identify the writable paths used by the Zabbix agent for OpenSSL configuration loading. They then craft malicious OpenSSL configuration files that reference malicious DLLs, which are subsequently loaded by the agent process with elevated privileges. This attack pattern aligns with ATT&CK techniques such as T1068, which covers local privilege escalation, and T1546, which involves event trigger exploitation. Organizations running vulnerable versions of Zabbix Agent on Windows systems face immediate risk of compromise, particularly in environments where Zabbix agents are installed with default configurations or where user access controls are not properly enforced. The vulnerability is especially dangerous in enterprise networks where Zabbix agents are deployed across multiple systems, as a single compromised agent can provide attackers with a foothold for lateral movement and broader network infiltration.
Mitigation strategies should focus on immediate patching of affected Zabbix versions, along with implementation of proper file access controls and path restrictions. Organizations should ensure that OpenSSL configuration files are loaded from secure, read-only locations that are not writable by low-privileged users. System administrators should conduct comprehensive vulnerability assessments to identify all instances of affected Zabbix agents and apply security patches promptly. Additional protective measures include implementing application whitelisting policies, monitoring for suspicious file modifications in system directories, and ensuring that Zabbix agents are configured with minimal required privileges. The remediation process should also include regular security audits of configuration file permissions and access controls to prevent similar issues from arising in the future, while maintaining compliance with security standards such as those outlined in NIST SP 800-53 and ISO 27001 frameworks.