CVE-2006-2162 in Nagios
Summary
by MITRE
Buffer overflow in CGI scripts in Nagios 1.x before 1.4 and 2.x before 2.3 allows remote attackers to execute arbitrary code via a negative content length (Content-Length) HTTP header.
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Analysis
by VulDB Data Team • 06/18/2019
The vulnerability described in CVE-2006-2162 represents a critical buffer overflow condition affecting Nagios monitoring software versions 1.x prior to 1.4 and 2.x prior to 2.3. This flaw resides within the CGI scripts that form a core component of Nagios's web interface, making it particularly dangerous as it targets the software's administrative access points. The vulnerability specifically manifests when the web server processes HTTP requests containing malformed Content-Length headers with negative values, creating a scenario where memory allocation calculations become corrupted and lead to exploitable buffer overflows.
The technical mechanism behind this vulnerability involves the improper handling of HTTP headers within Nagios's CGI components, which are responsible for processing web requests from administrators and users interacting with the monitoring system. When a negative value is provided in the Content-Length header, the CGI scripts fail to validate this input properly, resulting in incorrect memory allocation decisions. This allows attackers to manipulate the memory layout of the running process, potentially overwriting critical program variables or return addresses on the stack. The vulnerability falls under CWE-121, which categorizes stack-based buffer overflow conditions, and specifically aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications through malformed input handling.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a pathway to completely compromise the Nagios monitoring server. Since Nagios typically runs with elevated privileges to monitor system resources and services, successful exploitation could result in full system compromise, allowing attackers to access sensitive monitoring data, modify system configurations, or establish persistent backdoors. The web interface serves as a critical attack surface for organizations relying on Nagios for infrastructure monitoring, making this vulnerability particularly attractive to threat actors seeking to gain access to network monitoring capabilities.
Mitigation strategies for CVE-2006-2162 should prioritize immediate patching of affected Nagios installations to versions 1.4 or 2.3 and later, which contain proper input validation for Content-Length headers. Organizations should also implement network segmentation to limit access to Nagios web interfaces, enforce strong authentication mechanisms, and deploy intrusion detection systems capable of identifying malformed HTTP requests. Additionally, regular security auditing of web applications and input validation procedures should be conducted to prevent similar vulnerabilities from emerging in other components of the monitoring infrastructure. The vulnerability demonstrates the critical importance of proper input validation in web applications and serves as a reminder of the potential consequences when buffer overflow conditions are present in widely deployed monitoring tools.