CVE-2021-25994 in Userfrosting
Summary
by MITRE • 01/03/2022
In Userfrosting, versions v0.3.1 to v4.6.2 are vulnerable to Host Header Injection. By luring a victim application user to click on a link, an unauthenticated attacker can use the “forgot password” functionality to reset the victim’s password and successfully take over their account.
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Analysis
by VulDB Data Team • 01/05/2022
The vulnerability CVE-2021-25994 represents a critical host header injection flaw affecting Userfrosting versions ranging from v0.3.1 through v4.6.2. This security weakness resides in the application's handling of HTTP host headers during the password reset process, creating a pathway for unauthorized account takeover. The vulnerability is particularly concerning as it leverages the legitimate password reset functionality to execute malicious operations, making it difficult to distinguish from genuine user activities. The flaw enables attackers to manipulate the host header value in HTTP requests, which can then be used to construct malicious URLs that bypass security checks and redirect users to attacker-controlled domains.
The technical implementation of this vulnerability stems from improper validation and sanitization of host headers within the application's authentication flow. When users initiate a password reset request through the forgot password functionality, the application constructs password reset URLs that include the host header value from the HTTP request. An attacker can manipulate this header to point to a malicious domain, causing the reset link to appear legitimate to the victim while actually directing them to an attacker-controlled endpoint. This flaw falls under CWE-614, which specifically addresses sensitive data exposure through improper handling of host headers in web applications, and aligns with ATT&CK technique T1566.001 for the initial access phase through spearphishing with malicious links. The vulnerability is particularly dangerous because it operates at the application layer and can be exploited without authentication, making it an attractive target for automated attacks.
The operational impact of this vulnerability extends beyond simple account takeover, as it can enable broader compromise of the application ecosystem. An attacker who successfully takes over a victim's account can access sensitive data, modify user profiles, and potentially escalate privileges within the application. The attack vector is particularly effective because it exploits the trust relationship between the application and its users, using legitimate functionality to deliver malicious payloads. The vulnerability's exploitation requires minimal technical skill, making it accessible to threat actors across different skill levels. Organizations using affected versions of Userfrosting face significant risk of unauthorized access to user accounts, potential data breaches, and reputational damage from compromised user credentials. The attack can be executed through social engineering tactics, where victims are lured to click on malicious links that appear to be legitimate password reset emails.
Mitigation strategies for CVE-2021-25994 must address the core issue of host header validation within the application's authentication mechanisms. The primary solution involves implementing strict host header validation that verifies the host value against a predefined whitelist of legitimate domains rather than accepting user-provided values. Organizations should also implement proper URL construction practices that do not rely on user-supplied host headers for generating password reset links. Security patches should enforce the use of absolute URLs with hardcoded domain values during the password reset process, preventing attackers from manipulating the host header to redirect users. Additionally, implementing proper input validation and sanitization of HTTP headers, along with regular security audits of authentication flows, can help prevent similar vulnerabilities from emerging. Organizations should also consider implementing additional security controls such as rate limiting on password reset requests and monitoring for unusual patterns in authentication activities to detect potential exploitation attempts. The remediation process should include comprehensive testing to ensure that the patched version properly handles all host header scenarios while maintaining legitimate application functionality.