How to fix Broken User Authentication
in ServiceStack
Executive Summary
Broken User Authentication in ServiceStack typically manifests through insecure custom AuthProviders, failure to rotate session IDs, or weak password hashing configurations. In a 'hacker-style' context, we look for session fixation vulnerabilities or the ability to bypass the 'TryAuthenticate' logic when developers roll their own logic instead of leveraging the built-in IPasswordHasher. This guide forces the implementation of secure defaults to mitigate credential stuffing and session hijacking.
The Vulnerable Pattern
public class InsecureAuthProvider : CredentialsAuthProvider { public override bool TryAuthenticate(IServiceBase authService, string userName, string password) { // VULNERABILITY: Manual, weak MD5 hashing and no session regeneration var user = authService.TryResolve().Open().Single (u => u.UserName == userName); if (user != null && user.PasswordHash == password.ToMd5Hash()) { return true; } return false; } public override IHttpResult OnAuthenticated(IServiceBase authService, IAuthSession session, IAuthTokens tokens, Dictionary<string, string> authInfo) { // VULNERABILITY: Missing session ID regeneration after login (Session Fixation) return base.OnAuthenticated(authService, session, tokens, authInfo); }
}
The Secure Implementation
To fix broken authentication: 1. Set 'GenerateNewSessionCookiesOnAuthentication = true' to stop session fixation. 2. Implement 'IPasswordHasher' using Argon2Id to replace legacy MD5/SHA1 hashing. 3. Ensure 'AuthFeature' is configured to only transmit session identifiers over HTTPS by setting 'UseSecureCookies' (via HostConfig). 4. Never manually compare hashes in 'TryAuthenticate'; use 'Authenticate' methods that leverage the framework's timing-attack resistant comparisons.
public override void Configure(Container container) { Plugins.Add(new AuthFeature(() => new AuthUserSession(), new IAuthProvider[] { new CredentialsAuthProvider { // SECURE: Enforce Argon2 or Bcrypt via IPasswordHasher // ServiceStack uses SaltedHash by default, but Argon2 is preferred } }) { // SECURE: Prevent Session Fixation GenerateNewSessionCookiesOnAuthentication = true, // SECURE: Enforce HTTPS for cookies HtmlRedirect = "~/login", IncludeRegistrationService = true });// SECURE: Global attribute to require secure transport this.GlobalRequestFilters.Add((req, res, dto) => { if (!req.IsSecureConnection && !req.IsLocal) throw HttpError.Forbidden("SSL Required"); });
}
Your ServiceStack API
might be exposed to Broken User Authentication
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