CVE-2006-6693 in Zabbix
Summary
by MITRE
Multiple buffer overflows in zabbix before 20061006 allow attackers to cause a denial of service (application crash) and possibly execute arbitrary code via long strings to the (1) zabbix_log and (2) zabbix_syslog functions.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/18/2019
The vulnerability identified as CVE-2006-6693 represents a critical security flaw in the Zabbix monitoring system prior to version 20061006. This vulnerability manifests as multiple buffer overflows within the zabbix_log and zabbix_syslog functions, which are fundamental components of the Zabbix server's logging infrastructure. The flaw arises from inadequate input validation and bounds checking when processing log messages, creating opportunities for malicious actors to exploit the system through carefully crafted input strings that exceed allocated buffer sizes.
The technical implementation of this vulnerability stems from the lack of proper string length validation in the logging functions. When Zabbix processes log entries, it fails to enforce strict boundaries on the length of input data, allowing attackers to inject excessively long strings that overwrite adjacent memory locations. This buffer overflow condition occurs in the zabbix_log function where log messages are processed and stored, and similarly in zabbix_syslog which handles system log entries. The vulnerability operates at the application layer and can be triggered through various attack vectors that involve sending malformed log data to the Zabbix server.
The operational impact of CVE-2006-6693 extends beyond simple denial of service conditions to potentially enable remote code execution. When an attacker successfully exploits the buffer overflow, the application crash resulting from memory corruption can be leveraged to execute arbitrary code with the privileges of the Zabbix service account. This presents a severe risk to system integrity and confidentiality, as attackers could gain unauthorized access to monitoring data, manipulate system logs, or establish persistent access points within the network infrastructure. The vulnerability directly aligns with CWE-121, which describes stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter usage in executing malicious payloads.
Mitigation strategies for this vulnerability require immediate patching of Zabbix installations to version 20061006 or later, which includes proper input validation and buffer size enforcement. System administrators should implement input sanitization measures at network boundaries to filter out suspicious log data before it reaches the Zabbix server. Additionally, monitoring should be enhanced to detect unusual log message patterns that might indicate exploitation attempts. The implementation of address space layout randomization and stack canaries can provide additional defense-in-depth measures against exploitation. Organizations should also conduct regular security assessments of their monitoring infrastructure and maintain up-to-date vulnerability scanning procedures to identify similar weaknesses in other system components. This vulnerability highlights the importance of secure coding practices and the necessity of comprehensive input validation in all application components that handle external data processing.