CVE-2024-12907 in Kentico
Summary
by MITRE • 01/02/2025
Kentico CMS in version 7 is vulnerable to a Reflected XSS attacks through manipulation of a specific GET request parameter sent to /CMSMessages/AccessDenied.aspx endpoint. Notably, support for this version of Kentico ended in 2016. Version 8 was tested as well and does not contain this vulnerability.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2024-12907 affects Kentico CMS version 7 which reached end-of-life support in 2016, making this a legacy system security issue that continues to pose risks for organizations still operating deprecated software versions. This reflected cross-site scripting vulnerability specifically targets the /CMSMessages/AccessDenied.aspx endpoint within the CMS framework, representing a critical security flaw that allows attackers to inject malicious scripts into web pages viewed by other users. The vulnerability manifests through manipulation of a specific GET request parameter, indicating that the application fails to properly sanitize or encode user input before incorporating it into HTTP responses. This particular endpoint serves as an access denial page that would typically be invoked when users attempt to access restricted content, making it a high-value target for attackers seeking to exploit the system's input validation weaknesses. The reflected nature of this XSS attack means that malicious scripts are executed in the victim's browser through a crafted web request rather than being stored on the server, which makes the attack vector particularly dangerous as it can be delivered via email links or malicious websites.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the Kentico CMS version 7 codebase, specifically within the AccessDenied.aspx page handler. When the application processes the GET parameter, it directly incorporates user-supplied data into the HTTP response without proper sanitization or HTML encoding, creating an opening for malicious script injection. This flaw aligns with CWE-79 which defines cross-site scripting vulnerabilities as weaknesses that occur when an application includes untrusted data in a new web page without proper validation or encoding, or when it fails to escape special characters in output. The vulnerability represents a classic reflected XSS scenario where the malicious payload is embedded in the URL and executed when the victim clicks on the malicious link, making it particularly challenging to detect and prevent through traditional security measures. The fact that version 8 of the software does not contain this vulnerability suggests that the developers identified and addressed this specific input handling issue in their subsequent releases, highlighting the importance of maintaining current software versions.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with potential access to sensitive user sessions, credentials, or system information depending on the privileges of the affected users. An attacker could craft malicious URLs that, when clicked by authenticated users, could steal session cookies, redirect users to malicious sites, or perform actions on behalf of the victim within the CMS environment. This type of vulnerability is particularly concerning in content management systems where users may have elevated privileges and access to sensitive data. The reflected nature of the attack means that the vulnerability can be exploited through social engineering techniques, phishing campaigns, or by embedding malicious links in compromised websites, making it difficult to completely prevent without proper input validation. Organizations running unsupported software versions like Kentico CMS 7 face increased risk of exploitation, as they cannot benefit from security patches or updates that would address this specific vulnerability. The attack surface is further expanded by the fact that this vulnerability exists in a page that handles access denial scenarios, meaning that users who encounter this page during normal system operations may unknowingly trigger the malicious script execution.
Organizations should prioritize immediate remediation of this vulnerability by upgrading to a supported version of Kentico CMS, specifically version 8 or later, which has been verified to not contain this particular flaw. The upgrade process should include comprehensive testing to ensure that all custom modules and configurations continue to function properly after the upgrade. Additionally, organizations should implement network-level protections such as web application firewalls that can detect and block malicious requests targeting the specific vulnerable endpoint. Input validation should be strengthened at the application level by implementing proper encoding and sanitization of all user-supplied parameters, particularly those used in URL query strings and form submissions. Security teams should also conduct regular vulnerability assessments to identify other deprecated software components that may harbor similar vulnerabilities, as legacy systems often contain multiple unpatched security flaws. The use of security monitoring tools that can detect suspicious traffic patterns or attempts to exploit known vulnerabilities should be implemented to provide early warning of potential exploitation attempts. Organizations should also consider implementing content security policies and other browser-level protections to mitigate the impact of any remaining XSS vulnerabilities that may not have been fully addressed through application-level fixes. This vulnerability serves as a strong reminder of the critical importance of maintaining current software versions and the risks associated with operating legacy systems that no longer receive security updates or support from vendors.