CVE-2017-2122 in Nessus
Summary
by MITRE
Cross-site scripting vulnerability in Nessus versions 6.8.0, 6.8.1, 6.9.0, 6.9.1 and 6.9.2 allows remote authenticated attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 09/26/2020
The vulnerability identified as CVE-2017-2122 represents a critical cross-site scripting flaw within Tenable Nessus versions 6.8.0 through 6.9.2, exposing organizations to significant web application security risks. This vulnerability specifically affects the web interface of Nessus scanner, a widely deployed network security assessment tool used by security professionals to identify system vulnerabilities. The flaw allows authenticated attackers to inject malicious scripts into the web application, potentially compromising user sessions and enabling further attack vectors against the targeted environment. The vulnerability exists in the handling of user-supplied input within the Nessus web interface, creating an avenue for attackers to execute arbitrary code within the context of a victim's browser session.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output encoding within the Nessus web application components. Attackers can leverage this weakness by crafting malicious payloads that exploit the application's failure to properly sanitize user-provided data before rendering it in web pages. The vulnerability's impact is amplified by the fact that it affects multiple versions of Nessus, indicating a widespread exposure across the user base. The unspecified vectors suggest that the flaw may exist across various input points within the application's web interface, potentially including form fields, URL parameters, or other user-controllable inputs that are not adequately protected against script injection attacks. This type of vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications, where improper validation of user input allows execution of malicious scripts.
The operational impact of this vulnerability extends beyond simple script injection, as authenticated attackers with access to Nessus can potentially escalate their privileges and compromise the security posture of the entire scanning environment. When attackers can execute scripts within the context of authenticated users, they may access sensitive configuration data, manipulate scan results, or even gain access to underlying network resources that the Nessus scanner can reach. The attack surface is particularly concerning given that Nessus is commonly deployed in enterprise environments where it may have access to critical network infrastructure and sensitive data. This vulnerability directly violates the principle of least privilege and can enable attackers to establish persistent access to the security scanning infrastructure, potentially leading to further reconnaissance and exploitation of the broader network. The ATT&CK framework categorizes this as a web application attack vector that can be leveraged for initial access, privilege escalation, and persistence within the target environment.
Organizations utilizing affected Nessus versions should prioritize immediate remediation through official patches provided by Tenable, as the vulnerability allows remote exploitation by authenticated attackers. The recommended mitigation strategy involves upgrading to Nessus version 6.9.3 or later, which contains the necessary fixes to address the XSS vulnerability. Security administrators should also implement network segmentation and access controls to limit the exposure of Nessus web interfaces to trusted users only, reducing the potential attack surface. Additional protective measures include implementing web application firewalls to monitor and filter malicious requests, conducting regular security assessments of Nessus configurations, and establishing robust user access controls to minimize the risk of unauthorized access to the scanning platform. Organizations should also consider implementing security monitoring solutions that can detect anomalous behavior patterns consistent with XSS attack attempts, providing additional layers of defense against exploitation of this vulnerability.