CVE-2024-39097 in Gnuboard
Summary
by MITRE • 08/26/2024
There is an Open Redirect vulnerability in Gnuboard v6.0.4 and below via the `url` parameter in login path.
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Analysis
by VulDB Data Team • 10/31/2025
The vulnerability identified as CVE-2024-39097 represents a critical open redirect flaw within the Gnuboard content management system version 6.0.4 and earlier releases. This vulnerability specifically affects the login authentication path where the application fails to properly validate or sanitize the url parameter, creating a security loophole that malicious actors can exploit to redirect users to arbitrary external domains. The open redirect vulnerability allows attackers to craft malicious URLs that, when clicked by unsuspecting users, will redirect them to phishing sites or malicious domains while maintaining the appearance of legitimacy through the trusted Gnuboard interface. This flaw exists in the authentication flow where the system accepts user-provided redirect URLs without adequate validation, potentially enabling credential theft and social engineering attacks.
The technical implementation of this vulnerability stems from inadequate input validation within the login handler component of Gnuboard. When users attempt to access protected resources and are redirected to the login page, the application accepts the url parameter directly from the HTTP request without performing proper sanitization or domain verification checks. This parameter is then used to construct the redirect URL that users are sent to after successful authentication. The flaw aligns with CWE-601 Open Redirect vulnerability classification, which specifically addresses situations where web applications fail to validate redirect URLs, allowing attackers to redirect users to malicious sites. The vulnerability operates at the application layer and can be exploited through simple URL manipulation techniques, making it particularly dangerous due to its ease of exploitation and potential for widespread impact.
The operational impact of this vulnerability extends beyond simple redirection attacks and can facilitate sophisticated phishing campaigns targeting the organization's users. Attackers can craft deceptive URLs that appear to originate from the legitimate Gnuboard installation, tricking users into entering credentials on fraudulent sites that mimic the genuine login interface. This creates a significant risk of credential compromise and potential unauthorized access to sensitive system resources. The vulnerability also enables man-in-the-middle attacks where users may unknowingly navigate to malicious domains that could install malware or steal session cookies. According to ATT&CK framework, this vulnerability maps to T1566 Phishing and T1071.004 Application Layer Protocol HTTP, as it exploits the HTTP protocol to redirect users and leverages social engineering techniques to manipulate user behavior. The attack vector requires minimal technical skill from adversaries, making it particularly dangerous in environments where user awareness may be limited.
Mitigation strategies for CVE-2024-39097 should focus on immediate implementation of input validation and domain whitelisting mechanisms within the Gnuboard authentication flow. Organizations should implement strict validation of redirect URLs to ensure they only allow redirection to domains explicitly configured as trusted within the application configuration. The recommended approach involves maintaining a whitelist of approved redirect domains and rejecting any URLs that do not match these predefined values. Additionally, the application should implement proper URL parsing and validation routines that check for absolute URLs, protocol schemes, and domain names before processing redirect requests. Security patches should be applied immediately to upgrade to Gnuboard version 6.0.5 or later where this vulnerability has been addressed. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, though they should not be considered a substitute for proper application-level fixes. Regular security assessments and input validation reviews should be conducted to prevent similar vulnerabilities from emerging in other application components. Organizations should also implement user education programs to help staff recognize and report suspicious redirects, as the effectiveness of technical controls can be significantly reduced by human error in phishing scenarios.