CVE-2023-28874 in Seafile
Summary
by MITRE • 12/09/2023
The next parameter in the /accounts/login endpoint of Seafile 9.0.6 allows attackers to redirect users to arbitrary sites.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/07/2025
The vulnerability identified as CVE-2023-28874 represents a critical security flaw in the Seafile 9.0.6 web application that affects the authentication process through improper input validation. This issue resides within the /accounts/login endpoint where the application accepts a 'next' parameter that is intended to specify the destination page after successful authentication. The flaw occurs because the application fails to properly validate or sanitize this parameter, allowing attackers to manipulate the redirect behavior and potentially direct users to malicious websites. This type of vulnerability falls under the category of open redirect vulnerabilities that are commonly classified as CWE-601, which specifically addresses URL redirect vulnerabilities where user-provided input is used to construct redirect URLs without proper validation. The implications of such a flaw are significant as it can be exploited in phishing attacks where users are tricked into believing they are logging into a legitimate service while actually being redirected to an attacker-controlled site.
The technical execution of this vulnerability relies on the application's trust in user-provided input without adequate sanitization or validation of the redirect destination. When an attacker crafts a malicious URL containing a crafted 'next' parameter, they can manipulate the authentication flow to redirect users to domains they control. This typically involves constructing URLs such as https://target-seafile-server/accounts/login?next=http://malicious-site.com or similar variations that bypass the application's normal redirect validation mechanisms. The vulnerability is particularly dangerous because it operates at the application layer and can be exploited through various attack vectors including social engineering, where users are lured into clicking malicious links. The flaw demonstrates a lack of proper input validation and output encoding practices that should be implemented according to security best practices outlined in the OWASP Top Ten and the MITRE ATT&CK framework under the technique of 'T1566 - Phishing' and 'T1071.004 - Application Layer Protocol: DNS'. The attack surface is broad as it affects all users attempting to authenticate through the vulnerable endpoint.
The operational impact of CVE-2023-28874 extends beyond simple redirection attacks and can severely compromise user security and organizational integrity. Attackers can leverage this vulnerability to conduct sophisticated phishing campaigns where victims unknowingly provide credentials to attackers rather than legitimate service providers. The redirect mechanism can be used to display fake login pages that capture user credentials, effectively enabling credential theft attacks that can lead to unauthorized access to sensitive data stored within Seafile instances. Organizations using Seafile 9.0.6 are particularly vulnerable as this flaw affects the core authentication functionality, potentially allowing attackers to escalate privileges and gain access to shared documents, user accounts, and confidential information. The vulnerability also impacts the trust relationship between users and the application, as users may unknowingly navigate to malicious sites while believing they are performing legitimate authentication activities. This type of vulnerability can also facilitate broader attack chains where initial credential theft leads to further exploitation within the network infrastructure, making it a critical concern for enterprise security teams.
Mitigation strategies for CVE-2023-28874 must address the core validation issue within the application's redirect handling mechanism. Organizations should implement strict validation of the next parameter by either maintaining a whitelist of approved redirect destinations or by implementing proper URL validation that ensures redirect targets are within the application's domain or explicitly authorized paths. The recommended approach involves either completely removing the next parameter functionality or implementing robust input sanitization that validates redirect URLs against a predefined safe list. Security patches should be applied immediately to upgrade to versions of Seafile that address this vulnerability, as the maintainers have likely released fixes that properly validate and sanitize redirect parameters. Additional defensive measures include implementing proper logging and monitoring of authentication flows to detect unusual redirect patterns, configuring web application firewalls to block suspicious redirect parameters, and conducting regular security assessments of authentication endpoints. Organizations should also implement user education programs to help identify potential phishing attempts and establish clear policies for handling suspicious authentication redirects. The solution aligns with security standards such as those outlined in the NIST Cybersecurity Framework and should be part of comprehensive application security testing that includes dynamic application security testing and secure coding practices to prevent similar vulnerabilities in future development cycles.