CVE-2021-37353 in Nagios XI Docker Wizard
Summary
by MITRE • 08/13/2021
Nagios XI Docker Wizard before version 1.1.3 is vulnerable to SSRF due to improper sanitation in table_population.php.
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Analysis
by VulDB Data Team • 08/18/2021
The vulnerability identified as CVE-2021-37353 affects Nagios XI Docker Wizard versions prior to 1.1.3, presenting a significant server-side request forgery threat that stems from inadequate input validation within the table_population.php component. This flaw allows malicious actors to manipulate the application's behavior by injecting crafted requests that can bypass normal access controls and potentially access internal network resources that should remain restricted. The vulnerability resides in the wizard's handling of user-supplied data during table population operations, where insufficient sanitization enables attackers to construct requests that target internal systems or services that are typically not directly accessible from external networks.
The technical implementation of this vulnerability demonstrates a classic server-side request forgery pattern where the application fails to properly validate and sanitize user input before using it in HTTP requests to internal resources. When the table_population.php script processes data from the Docker wizard interface, it does not adequately filter or validate parameters that could contain malicious URLs or internal network addresses. This creates an attack surface where an attacker can manipulate the application to make HTTP requests to arbitrary internal endpoints, potentially leading to information disclosure, internal network reconnaissance, or further exploitation of vulnerable internal services. The flaw specifically manifests when the wizard attempts to populate tables with data from external sources, and user input is directly incorporated into the target URL without proper validation mechanisms.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to internal network resources that are typically protected by firewalls and network segmentation policies. An attacker could leverage this SSRF vulnerability to probe internal services, access sensitive configuration data, or even escalate privileges within the internal network environment. The attack vector is particularly concerning because it targets the installation and configuration wizard component, which is often accessible during initial system setup or maintenance operations when security controls may be less stringent. This vulnerability aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities, and represents a significant risk to organizations implementing Nagios XI systems in environments where internal network access should be restricted.
Mitigation strategies for CVE-2021-37353 should prioritize immediate patching of the Nagios XI Docker Wizard to version 1.1.3 or later, which includes proper input sanitization and validation mechanisms. Organizations should also implement network segmentation to restrict access to internal resources from the application servers hosting the wizard component, and consider implementing web application firewalls that can detect and block suspicious request patterns. Additional defensive measures include disabling the wizard component when not actively needed for configuration, implementing strict input validation at multiple layers of the application architecture, and conducting regular security assessments to identify similar vulnerabilities in other components. The vulnerability demonstrates the importance of following secure coding practices and adheres to ATT&CK technique T1190, which covers exploitation of remote services, making it a critical target for security hardening and monitoring efforts within enterprise environments.