CVE-2018-15712 in Nagios XI
Summary
by MITRE
Nagios XI 5.5.6 allows reflected cross site scripting from remote unauthenticated attackers via the host parameter in api_tool.php.
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Analysis
by VulDB Data Team • 04/12/2020
The vulnerability identified as CVE-2018-15712 represents a critical reflected cross site scripting flaw in Nagios XI version 5.5.6, a widely deployed network monitoring and management platform. This issue specifically affects the api_tool.php component which processes user input without adequate sanitization, creating an avenue for malicious actors to inject arbitrary script code into web responses. The vulnerability is particularly concerning because it requires no authentication to exploit, making it accessible to any remote attacker who can craft a malicious URL. The host parameter serves as the primary injection point, allowing attackers to manipulate the application's response and potentially execute malicious scripts within the context of a victim's browser session. This type of vulnerability falls under the CWE-79 category, which specifically addresses cross site scripting flaws where untrusted data is incorporated into web pages without proper validation or encoding.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing crafted script code within the host parameter of api_tool.php. When a victim clicks such a link or navigates to the malicious page, the script code becomes embedded in the web response and executes within the victim's browser context. The reflected nature of this XSS means that the malicious script is not stored on the server but is instead reflected back to the user through the vulnerable parameter, making it particularly challenging to detect and prevent through traditional server-side security measures. The impact extends beyond simple script execution as attackers can leverage this vulnerability to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. This vulnerability directly aligns with ATT&CK technique T1059.007 for scripting and T1566.001 for spearphishing through social engineering, demonstrating how such flaws can be weaponized in broader attack campaigns.
The operational impact of CVE-2018-15712 in Nagios XI environments is significant, particularly in enterprise monitoring scenarios where the platform serves as a central point for network visibility and alerting. Attackers exploiting this vulnerability could gain unauthorized access to sensitive monitoring data, potentially compromising the integrity of network security operations and alerting systems. The unauthenticated nature of the exploit means that attackers can compromise systems without requiring valid credentials, making detection more difficult and the attack surface larger. Organizations using Nagios XI may experience unauthorized access to monitoring dashboards, potential data exfiltration from monitoring interfaces, and the possibility of attackers using the platform as a pivot point for further attacks within the network. The vulnerability affects not only the immediate web interface but also any automated monitoring workflows that rely on the platform's API functionality, potentially disrupting critical network operations and security monitoring processes.
Mitigation strategies for this vulnerability should prioritize immediate patching of Nagios XI to version 5.5.7 or later, which contains the necessary fixes for the reflected XSS issue. Organizations should also implement comprehensive input validation and output encoding mechanisms throughout the application, particularly for parameters like host that are frequently used in API interactions. Network segmentation and web application firewalls can provide additional layers of protection by monitoring for suspicious patterns in API requests and blocking known malicious payloads. Security teams should conduct regular vulnerability assessments of monitoring platforms and maintain up-to-date threat intelligence to identify potential exploitation attempts. The implementation of Content Security Policy headers and proper HTTP response headers can further reduce the impact of potential exploitation attempts. Organizations should also establish incident response procedures specifically for monitoring platform compromises, as these systems often serve as critical infrastructure for security operations and their compromise can have cascading effects throughout the organization's security posture.