CVE-2013-6824 in Zabbix
Summary
by MITRE
Zabbix before 1.8.19rc1, 2.0 before 2.0.10rc1, and 2.2 before 2.2.1rc1 allows remote Zabbix servers and proxies to execute arbitrary commands via a newline in a flexible user parameter.
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Analysis
by VulDB Data Team • 01/18/2022
The vulnerability identified as CVE-2013-6824 represents a critical command injection flaw in the Zabbix monitoring platform that affects multiple version branches including 1.8.19rc1, 2.0.10rc1, and 2.2.1rc1. This issue stems from insufficient input validation in the flexible user parameter functionality, which permits remote attackers to execute arbitrary commands on affected systems. The vulnerability specifically exploits how the system processes user parameters that contain newline characters, creating a pathway for malicious command injection attacks. The flaw exists within the Zabbix server and proxy components that handle flexible user parameters, making it particularly dangerous as it can be leveraged by unauthorized users to gain elevated privileges and execute malicious code on monitored systems.
The technical exploitation of this vulnerability occurs through the manipulation of flexible user parameters that are processed by Zabbix's internal command execution mechanisms. When a newline character is included in a flexible user parameter, it allows attackers to inject additional commands that bypass normal input sanitization checks. This creates a command injection vector where the system interprets the newline as a command separator, enabling attackers to append malicious commands to legitimate monitoring requests. The vulnerability is classified under CWE-77 as a command injection flaw, specifically demonstrating how improper handling of user-supplied data can lead to arbitrary code execution. The attack typically involves crafting a malicious flexible user parameter that includes a newline character followed by the desired command, which then gets executed by the Zabbix server or proxy with the privileges of the monitoring service.
The operational impact of this vulnerability is severe and multifaceted, as it can lead to complete system compromise of Zabbix servers and proxies that are not properly patched. Attackers can leverage this vulnerability to execute arbitrary commands on the affected systems, potentially gaining access to sensitive monitoring data, escalating privileges, or even using the compromised monitoring infrastructure to launch further attacks against the internal network. The vulnerability affects the integrity and confidentiality of monitoring data, as attackers can manipulate or extract information from the monitoring environment. From an attack perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries use legitimate system tools to execute malicious commands. The impact extends beyond individual system compromise to potentially disrupt critical infrastructure monitoring capabilities, as Zabbix servers often serve as central points for system health monitoring and alerting.
Organizations should immediately implement mitigations including upgrading to patched versions of Zabbix that address this vulnerability, specifically versions 1.8.19rc1, 2.0.10rc1, and 2.2.1rc1 or later. Network segmentation and access controls should be implemented to restrict access to Zabbix servers and proxies, limiting exposure to potential attackers. Input validation should be enhanced at all levels where user parameters are processed, with strict sanitization of newline characters and other potentially dangerous input sequences. Regular monitoring of system logs for suspicious command execution patterns and implementing intrusion detection systems can help identify exploitation attempts. Security teams should also conduct thorough vulnerability assessments of their Zabbix deployments to ensure all instances are properly patched and configured according to security best practices. The vulnerability demonstrates the importance of proper input validation and output encoding in preventing command injection attacks, particularly in monitoring and management systems that execute user-supplied commands.