CVE-2017-2825 in Server
Summary
by MITRE
In the trapper functionality of Zabbix Server 2.4.x, specifically crafted trapper packets can pass database logic checks, resulting in database writes. An attacker can set up a Man-in-the-Middle server to alter trapper requests made between an active Zabbix proxy and Server to trigger this vulnerability.
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Analysis
by VulDB Data Team • 01/29/2020
The vulnerability identified as CVE-2017-2825 represents a critical security flaw within the trapper functionality of Zabbix Server version 2.4.x, which operates under the Common Weakness Enumeration framework as a CWE-1216 - Improper Database Query Logic. This vulnerability stems from insufficient validation mechanisms within the database interaction layer of the Zabbix server's trapper component, which is designed to receive data from Zabbix proxies in active monitoring scenarios. The trapper functionality serves as a critical communication channel where proxy servers transmit monitoring data to the central Zabbix server, making it a prime target for malicious actors seeking to compromise the monitoring infrastructure.
The technical exploitation of this vulnerability occurs through the manipulation of trapper packets that are normally transmitted between Zabbix proxies and the server. Attackers can craft specially designed packets that bypass the standard database logic checks implemented by the Zabbix server, allowing them to inject malicious data directly into the database. This occurs because the server's input validation process fails to properly sanitize or verify the integrity of incoming trapper requests, creating a path for unauthorized database modifications. The vulnerability specifically targets the database write operations that occur when the server processes these trapper packets, enabling attackers to manipulate monitoring data or potentially inject malicious entries.
The operational impact of this vulnerability extends beyond simple data manipulation, as it fundamentally compromises the integrity of the entire monitoring system. An attacker who successfully exploits this vulnerability can alter critical monitoring data, potentially leading to false security alerts, corrupted performance metrics, or even complete data poisoning that undermines the reliability of the entire Zabbix infrastructure. The man-in-the-middle attack vector described in the vulnerability requires minimal privileges and can be executed without authentication, making it particularly dangerous as it allows attackers to exploit the trust relationship between the proxy and server components. This attack method leverages the inherent trust model of the Zabbix architecture where proxies are trusted to communicate legitimate data to the server.
The exploitation of CVE-2017-2825 aligns with several tactics outlined in the MITRE ATT&CK framework, particularly under the Tactic of Credential Access and the technique of Valid Accounts, as attackers can leverage the existing proxy-server communication channels to execute their malicious activities. The vulnerability also relates to the Privilege Escalation category as it allows attackers to gain unauthorized access to database write capabilities that should be restricted to legitimate system components. Organizations using Zabbix Server 2.4.x are particularly vulnerable as this version lacks proper input validation and sanitization mechanisms that would normally prevent such database injection attacks. The attack surface is further expanded by the fact that Zabbix proxies are often deployed in environments where they may not be properly secured, creating additional entry points for attackers to establish the man-in-the-middle position required to exploit this vulnerability.
Mitigation strategies for CVE-2017-2825 should focus on immediate patching of the Zabbix Server to versions that address the database logic validation issues, while also implementing network-level controls to prevent unauthorized man-in-the-middle attacks. Organizations should consider implementing network segmentation and secure communication protocols between proxies and servers to reduce the attack surface. The implementation of proper input validation, database query sanitization, and monitoring of database write operations should be prioritized as part of a comprehensive security posture. Additionally, regular security assessments of monitoring infrastructure components are essential to identify similar vulnerabilities in other system components that may share similar architectural patterns to the affected Zabbix trapper functionality.