CVE-2021-26023 in Favorites Component
Summary
by MITRE • 02/04/2021
The Favorites component before 1.0.2 for Nagios XI 5.8.0 is vulnerable to XSS.
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Analysis
by VulDB Data Team • 02/23/2021
The vulnerability identified as CVE-2021-26023 affects the Favorites component within Nagios XI version 5.8.0, specifically before version 1.0.2. This represents a cross-site scripting vulnerability that could potentially allow attackers to execute malicious scripts in the context of a victim's browser session. The affected system is part of the broader Nagios XI monitoring platform, which is widely used for network and system monitoring in enterprise environments. The vulnerability resides within the Favorites functionality, which allows users to bookmark and organize their frequently accessed monitoring views and configurations. This component is particularly concerning as it forms part of the user interface that administrators and operators interact with regularly during system monitoring activities.
The technical flaw manifests as a failure to properly sanitize user input within the Favorites component, enabling an attacker to inject malicious script code through specially crafted input fields or parameters. When a victim views a page containing the maliciously injected script, the code executes in the victim's browser with the privileges of the logged-in user. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS variant where the malicious payload is permanently stored on the server and executed when other users access the affected page. The attack vector typically involves an authenticated user with sufficient privileges to modify Favorites settings, though in some cases the vulnerability may be exploitable by unauthenticated attackers depending on the specific implementation details.
The operational impact of this vulnerability extends beyond simple script execution, as it could potentially enable attackers to escalate privileges, steal session cookies, perform unauthorized actions on behalf of legitimate users, or redirect victims to malicious websites. In a monitoring environment like Nagios XI, where administrators often have elevated privileges and access to critical system information, the potential for damage is significant. An attacker who successfully exploits this vulnerability could gain access to sensitive monitoring data, compromise the integrity of system alerts, or use the compromised session to make unauthorized configuration changes. The vulnerability also poses risks to the overall security posture of the network monitoring infrastructure, potentially allowing lateral movement within the environment if the compromised user has access to multiple systems or monitoring components.
Mitigation strategies for CVE-2021-26023 should prioritize immediate patching of the affected Nagios XI installation to version 1.0.2 or later, which contains the necessary security fixes. Organizations should also implement additional protective measures such as input validation and output encoding for all user-supplied data within the Favorites component and similar interface elements. Network segmentation and the principle of least privilege should be enforced to limit the potential impact of any successful exploitation. Security monitoring should be enhanced to detect suspicious activities related to Favorites modifications, and regular security assessments should be conducted to identify similar vulnerabilities in other components of the Nagios XI platform. The ATT&CK framework categorizes this vulnerability under T1566 for Phishing and T1059 for Command and Scripting Interpreter, highlighting the need for both preventive measures and detection capabilities. Organizations should also consider implementing web application firewalls and content security policies to add additional layers of protection against similar cross-site scripting vulnerabilities in their monitoring and management interfaces.