CVE-2013-3738 in Zabbix
Summary
by MITRE
A File Inclusion vulnerability exists in Zabbix 2.0.6 due to inadequate sanitization of request strings in CGI scripts, which could let a remote malicious user execute arbitrary code.
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Analysis
by VulDB Data Team • 04/22/2023
The vulnerability identified as CVE-2013-3738 represents a critical file inclusion flaw in Zabbix version 2.0.6 that stems from insufficient input validation within the web interface's CGI scripts. This weakness creates an exploitable condition where attacker-controlled input can be processed without proper sanitization, allowing for unauthorized code execution. The vulnerability specifically affects the Zabbix monitoring system's web frontend components that handle user requests through CGI interfaces, making it particularly dangerous for environments where Zabbix serves as a central monitoring solution for critical infrastructure. The flaw resides in the application's failure to properly validate and sanitize user-supplied parameters that are subsequently used in file inclusion operations, creating a pathway for remote code execution attacks.
The technical implementation of this vulnerability occurs when the CGI scripts process user input through parameters that are directly incorporated into file path constructions without adequate validation. Attackers can manipulate these parameters to include malicious file paths or payloads that the application then attempts to load and execute. This type of vulnerability falls under the CWE-434 category, which specifically addresses "Unrestricted Upload of File with Dangerous Type," though in this case the issue manifests as an unrestricted file inclusion rather than an upload vulnerability. The exploitation process typically involves crafting malicious HTTP requests that target the vulnerable CGI endpoints, where user input is accepted and then processed in a manner that allows arbitrary file inclusion. The vulnerability is particularly concerning because it enables attackers to execute arbitrary code with the privileges of the web server process, potentially leading to complete system compromise.
The operational impact of CVE-2013-3738 extends beyond simple code execution to encompass full system compromise and data exfiltration capabilities. Organizations running Zabbix 2.0.6 are at significant risk of unauthorized access to their monitoring infrastructure, which often contains sensitive operational data and system information. The vulnerability can be exploited remotely without authentication, making it particularly attractive to threat actors who seek to gain persistent access to network monitoring systems. Once exploited, attackers can establish backdoors, escalate privileges, or use the compromised system as a launch point for further attacks within the network. The monitoring nature of Zabbix makes it a valuable target, as the compromised system may provide insights into other network segments or contain access credentials that could be leveraged for additional lateral movement. This vulnerability directly maps to several ATT&CK techniques including T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, demonstrating the multi-faceted attack surface it creates.
Organizations should immediately implement mitigation strategies to address this vulnerability, beginning with upgrading to a patched version of Zabbix that resolves the input sanitization issues in the CGI scripts. The recommended remediation approach involves applying the vendor-provided security patches or upgrading to Zabbix 2.0.7 or later versions where the vulnerability has been addressed through proper input validation and sanitization mechanisms. Network segmentation and access controls should be implemented to limit exposure of the Zabbix web interface to untrusted networks, while monitoring for suspicious requests containing unusual parameter values or file path references. Additionally, implementing web application firewalls and input validation rules can help detect and block exploitation attempts before they can succeed. Security teams should also conduct thorough audits of their Zabbix installations to identify any custom configurations or extensions that might introduce similar vulnerabilities, and maintain comprehensive logging of all web interface interactions for forensic analysis purposes. The vulnerability demonstrates the critical importance of input validation in web applications and serves as a reminder of the potential consequences when sanitization mechanisms fail to properly validate user-supplied data before processing.