CVE-2016-9757 in Nexpose
Summary
by MITRE
In the Create Tags page of the Rapid7 Nexpose version 6.4.12 user interface, any authenticated user who has the capability to create tags can inject cross-site scripting (XSS) elements in the tag name field. For example, a tag name such as "A</script><script>alert('XSS')</script>B" is sufficient to exploit the vulnerability. Once this tag is viewed in the Tag Detail page of the Rapid7 Nexpose 6.4.12 UI by another authenticated user, the script is run in that user's browser context.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-9757 represents a critical cross-site scripting flaw within the Rapid7 Nexpose security assessment platform version 6.4.12. This vulnerability exists in the Create Tags page functionality of the web user interface, where insufficient input validation and output encoding allow malicious users to inject harmful script code into tag names. The flaw specifically affects authenticated users who possess the privilege to create tags, making it particularly concerning as it can be exploited by insiders or compromised accounts with appropriate permissions. The vulnerability manifests when a user creates a tag with malicious script content in the tag name field, such as the example payload "A</script><script>alert('XSS')</script>B" which demonstrates how easily the injection can occur through simple manipulation of the input field.
The technical exploitation of this vulnerability occurs through improper sanitization of user input within the web application's tag creation functionality. When an authenticated user creates a tag with malicious script content, the application fails to properly encode or validate the input before storing and subsequently displaying it in the Tag Detail page. This failure creates a persistent XSS vector where the malicious script code becomes part of the web page content and executes within the browser context of any user who views the affected tag details. The vulnerability is classified as a classic stored XSS attack pattern, where the malicious payload is stored on the server and executed when other users access the vulnerable page, rather than requiring a direct browser-based attack vector. This type of vulnerability is categorized under CWE-79 in the Common Weakness Enumeration system, which specifically addresses cross-site scripting flaws due to improper input handling and output encoding.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities within the context of the affected users' browser sessions. An attacker with tag creation privileges could potentially steal session cookies, perform actions on behalf of other users, redirect victims to malicious websites, or extract sensitive information from the application. The vulnerability is particularly dangerous in enterprise environments where security professionals might be targeted, as it could allow adversaries to compromise the security monitoring capabilities of the platform itself. The fact that this affects a core administrative function like tagging makes it especially concerning, as it could be used to manipulate security data, hide malicious activities, or escalate privileges within the application's access control framework.
Mitigation strategies for CVE-2016-9757 should focus on implementing comprehensive input validation and output encoding mechanisms throughout the application's user interface components. The primary fix involves sanitizing all user-supplied input before storing or rendering it within web pages, ensuring that script tags and other potentially dangerous elements are properly escaped or removed. Organizations should implement strict validation of tag names to prevent the inclusion of HTML or script elements, while also applying proper context-aware output encoding when displaying user content. Additionally, implementing content security policies and using security headers can provide additional layers of protection against XSS attacks. The vulnerability highlights the importance of secure coding practices and input validation, as recommended in the OWASP Top Ten and MITRE ATT&CK framework for web application security. Organizations using Rapid7 Nexpose should immediately apply the vendor-provided security patches or upgrade to versions that address this vulnerability, while also reviewing their access control policies to limit tag creation privileges to trusted users only.