CVE-2012-6086 in Zabbix
Summary
by MITRE
libs/zbxmedia/eztexting.c in Zabbix 1.8.x before 1.8.18rc1, 2.0.x before 2.0.8rc1, and 2.1.x before 2.1.2 does not properly set the CURLOPT_SSL_VERIFYHOST option for libcurl, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability identified as CVE-2012-6086 resides within the Zabbix monitoring system's communication library implementation, specifically in the eztexting.c file located in the libs/zbxmedia directory. This flaw affects multiple versions of the Zabbix software including 1.8.x versions prior to 1.8.18rc1, 2.0.x versions before 2.0.8rc1, and 2.1.x versions before 2.1.2. The issue stems from improper configuration of the CURLOPT_SSL_VERIFYHOST option within the libcurl library integration, creating a critical security weakness that undermines the integrity of SSL/TLS communications between Zabbix components and external systems.
The technical flaw represents a failure in SSL certificate validation where the CURLOPT_SSL_VERIFYHOST option is not correctly configured to verify SSL server certificates. This misconfiguration allows attackers to perform man-in-the-middle attacks by presenting arbitrary valid certificates that would otherwise be rejected by proper SSL verification mechanisms. The vulnerability specifically impacts the Zabbix media configuration functionality that handles text messaging communications, where the system attempts to establish secure connections to external SMS gateway services. When this option is not properly set, the libcurl library fails to validate that the SSL certificate presented by the remote server matches the expected host, enabling attackers to intercept and potentially manipulate communications between Zabbix and its configured media handlers.
The operational impact of this vulnerability is significant for organizations relying on Zabbix for system monitoring and alerting, particularly those that utilize SMS notifications or other media types that require secure communication channels. Attackers exploiting this weakness could intercept sensitive alert notifications, potentially gaining access to critical system information, or could inject false alerts that might cause operational disruption. The vulnerability is particularly dangerous in environments where Zabbix is configured to send security-related alerts via text messaging, as this could enable attackers to eavesdrop on security events or manipulate alerting mechanisms. The flaw affects the authentication and integrity of communications within the Zabbix ecosystem, potentially compromising the entire monitoring infrastructure's trust model.
Organizations should immediately apply the patched versions of Zabbix that address this vulnerability, specifically upgrading to 1.8.18rc1 or later for the 1.8.x branch, 2.0.8rc1 or later for the 2.0.x branch, and 2.1.2 or later for the 2.1.x branch. The fix involves properly setting the CURLOPT_SSL_VERIFYHOST option to ensure that SSL certificates are validated against the expected hostnames, thereby preventing man-in-the-middle attacks. Additionally, security teams should conduct comprehensive network monitoring to detect any potential exploitation attempts and review all Zabbix configurations to ensure that all SSL communications are properly secured. This vulnerability aligns with CWE-295 which addresses improper certificate validation and relates to ATT&CK technique T1566 which covers credential access through man-in-the-middle attacks. Organizations should also consider implementing additional network security controls such as SSL inspection and monitoring for unusual communication patterns that might indicate exploitation attempts.