CVE-2025-24806 (Go)

Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. If users are allowed to sign in via both username and email the regulation system treats these as separate login events. This leads to the regulation limitations being effectively doubled assuming an attacker using brute-force to find a user password. It's important to note that due to the effective operation of regulation where no user-facing sign of their regulation ban being visible either via timing or via API responses, it's effectively impossible to determine if a failure occurs due to a bad username password combination, or a effective ban blocking the attempt which heavily mitigates any form of brute-force. This occurs because the records and counting process for this system uses the method utilized for sign in rather than the effective username attribute. This has a minimal impact on account security, this impact is increased naturally in scenarios when there is no two-factor authentication required and weak passwords are used. This makes it a bit easier to brute-force a password. A patch for this issue has been applied to versions 4.38.19, and 4.39.0. Users are advised to upgrade. Users unable to upgrade should 1. Not heavily modify the default settings in a way that ends up with shorter or less frequent regulation bans. The default settings effectively mitigate any potential for this issue to be exploited. and 2. Disable the ability for users to login via an email address.

Weakness:
CWE-307: name: Improper Restriction of Excessive Authentication Attempts
description: The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.

Repository: https://github.com/authelia/authelia

Vulnerable code:
file_path: internal/handlers/handler_firstfactor.go
snippet: func FirstFactorPOST(delayFunc middlewares.TimingAttackDelayFunc) middlewares.RequestHandler {
	return func(ctx *middlewares.AutheliaCtx) {
		var successful bool

		requestTime := time.Now()

		if delayFunc != nil {
			defer delayFunc(ctx, requestTime, &successful)
		}

		bodyJSON := bodyFirstFactorRequest{}

		if err := ctx.ParseBody(&bodyJSON); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrParseRequestBody, regulation.AuthType1FA)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if bannedUntil, err := ctx.Providers.Regulator.Regulate(ctx, bodyJSON.Username); err != nil {
			if errors.Is(err, regulation.ErrUserIsBanned) {
				_ = markAuthenticationAttempt(ctx, false, &bannedUntil, bodyJSON.Username, regulation.AuthType1FA, nil)

				respondUnauthorized(ctx, messageAuthenticationFailed)

				return
			}

			ctx.Logger.WithError(err).Errorf(logFmtErrRegulationFail, regulation.AuthType1FA, bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		userPasswordOk, err := ctx.Providers.UserProvider.CheckUserPassword(bodyJSON.Username, bodyJSON.Password)
		if err != nil {
			_ = markAuthenticationAttempt(ctx, false, nil, bodyJSON.Username, regulation.AuthType1FA, err)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if !userPasswordOk {
			_ = markAuthenticationAttempt(ctx, false, nil, bodyJSON.Username, regulation.AuthType1FA, nil)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if err = markAuthenticationAttempt(ctx, true, nil, bodyJSON.Username, regulation.AuthType1FA, nil); err != nil {
			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		provider, err := ctx.GetSessionProvider()
		if err != nil {
			ctx.Logger.WithError(err).Error("Failed to get session provider during 1FA attempt")

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		userSession, err := provider.GetSession(ctx.RequestCtx)
		if err != nil {
			ctx.Logger.Errorf("%s", err)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		newSession := provider.NewDefaultUserSession()

		// Reset all values from previous session except OIDC workflow before regenerating the cookie.
		if err = ctx.SaveSession(newSession); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionReset, regulation.AuthType1FA, bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if err = ctx.RegenerateSession(); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionRegenerate, regulation.AuthType1FA, bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		// Check if bodyJSON.KeepMeLoggedIn can be deref'd and derive the value based on the configuration and JSON data.
		keepMeLoggedIn := !provider.Config.DisableRememberMe && bodyJSON.KeepMeLoggedIn != nil && *bodyJSON.KeepMeLoggedIn

		// Set the cookie to expire if remember me is enabled and the user has asked us to.
		if keepMeLoggedIn {
			err = provider.UpdateExpiration(ctx.RequestCtx, provider.Config.RememberMe)
			if err != nil {
				ctx.Logger.WithError(err).Errorf(logFmtErrSessionSave, "updated expiration", regulation.AuthType1FA, logFmtActionAuthentication, bodyJSON.Username)

				respondUnauthorized(ctx, messageAuthenticationFailed)

				return
			}
		}

		// Get the details of the given user from the user provider.
		userDetails, err := ctx.Providers.UserProvider.GetDetails(bodyJSON.Username)
		if err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrObtainProfileDetails, regulation.AuthType1FA, bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		ctx.Logger.Tracef(logFmtTraceProfileDetails, bodyJSON.Username, userDetails.Groups, userDetails.Emails)

		userSession.SetOneFactor(ctx.Clock.Now(), userDetails, keepMeLoggedIn)

		if ctx.Configuration.AuthenticationBackend.RefreshInterval.Update() {
			userSession.RefreshTTL = ctx.Clock.Now().Add(ctx.Configuration.AuthenticationBackend.RefreshInterval.Value())
		}

		if err = ctx.SaveSession(userSession); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionSave, "updated profile", regulation.AuthType1FA, logFmtActionAuthentication, bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		successful = true

		if bodyJSON.Workflow == workflowOpenIDConnect {
			handleOIDCWorkflowResponse(ctx, &userSession, bodyJSON.TargetURL, bodyJSON.WorkflowID)
		} else {
			Handle1FAResponse(ctx, bodyJSON.TargetURL, bodyJSON.RequestMethod, userSession.Username, userSession.Groups)
		}
	}
}

Fixed code:
file_path: internal/handlers/handler_firstfactor.go
snippet: func FirstFactorPOST(delayFunc middlewares.TimingAttackDelayFunc) middlewares.RequestHandler {
	return func(ctx *middlewares.AutheliaCtx) {
		var successful bool

		requestTime := time.Now()

		if delayFunc != nil {
			defer delayFunc(ctx, requestTime, &successful)
		}

		bodyJSON := bodyFirstFactorRequest{}

		var (
			details *authentication.UserDetails
			err     error
		)

		if err = ctx.ParseBody(&bodyJSON); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrParseRequestBody, regulation.AuthType1FA)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if details, err = ctx.Providers.UserProvider.GetDetails(bodyJSON.Username); err != nil || details == nil {
			ctx.Logger.WithError(err).Errorf("Error occurred getting details for user with username input '%s' which usually indicates they do not exist", bodyJSON.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if bannedUntil, err := ctx.Providers.Regulator.Regulate(ctx, details.Username); err != nil {
			if errors.Is(err, regulation.ErrUserIsBanned) {
				_ = markAuthenticationAttempt(ctx, false, &bannedUntil, details.Username, regulation.AuthType1FA, nil)

				respondUnauthorized(ctx, messageAuthenticationFailed)

				return
			}

			ctx.Logger.WithError(err).Errorf(logFmtErrRegulationFail, regulation.AuthType1FA, details.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		userPasswordOk, err := ctx.Providers.UserProvider.CheckUserPassword(details.Username, bodyJSON.Password)
		if err != nil {
			_ = markAuthenticationAttempt(ctx, false, nil, details.Username, regulation.AuthType1FA, err)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if !userPasswordOk {
			_ = markAuthenticationAttempt(ctx, false, nil, details.Username, regulation.AuthType1FA, nil)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if err = markAuthenticationAttempt(ctx, true, nil, details.Username, regulation.AuthType1FA, nil); err != nil {
			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		provider, err := ctx.GetSessionProvider()
		if err != nil {
			ctx.Logger.WithError(err).Error("Failed to get session provider during 1FA attempt")

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		userSession, err := provider.GetSession(ctx.RequestCtx)
		if err != nil {
			ctx.Logger.Errorf("%s", err)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		newSession := provider.NewDefaultUserSession()

		// Reset all values from previous session except OIDC workflow before regenerating the cookie.
		if err = ctx.SaveSession(newSession); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionReset, regulation.AuthType1FA, details.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		if err = ctx.RegenerateSession(); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionRegenerate, regulation.AuthType1FA, details.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		// Check if bodyJSON.KeepMeLoggedIn can be deref'd and derive the value based on the configuration and JSON data.
		keepMeLoggedIn := !provider.Config.DisableRememberMe && bodyJSON.KeepMeLoggedIn != nil && *bodyJSON.KeepMeLoggedIn

		// Set the cookie to expire if remember me is enabled and the user has asked us to.
		if keepMeLoggedIn {
			err = provider.UpdateExpiration(ctx.RequestCtx, provider.Config.RememberMe)
			if err != nil {
				ctx.Logger.WithError(err).Errorf(logFmtErrSessionSave, "updated expiration", regulation.AuthType1FA, logFmtActionAuthentication, details.Username)

				respondUnauthorized(ctx, messageAuthenticationFailed)

				return
			}
		}

		ctx.Logger.Tracef(logFmtTraceProfileDetails, details.Username, details.Groups, details.Emails)

		userSession.SetOneFactor(ctx.Clock.Now(), details, keepMeLoggedIn)

		if ctx.Configuration.AuthenticationBackend.RefreshInterval.Update() {
			userSession.RefreshTTL = ctx.Clock.Now().Add(ctx.Configuration.AuthenticationBackend.RefreshInterval.Value())
		}

		if err = ctx.SaveSession(userSession); err != nil {
			ctx.Logger.WithError(err).Errorf(logFmtErrSessionSave, "updated profile", regulation.AuthType1FA, logFmtActionAuthentication, details.Username)

			respondUnauthorized(ctx, messageAuthenticationFailed)

			return
		}

		successful = true

		if bodyJSON.Workflow == workflowOpenIDConnect {
			handleOIDCWorkflowResponse(ctx, &userSession, bodyJSON.TargetURL, bodyJSON.WorkflowID)
		} else {
			Handle1FAResponse(ctx, bodyJSON.TargetURL, bodyJSON.RequestMethod, userSession.Username, userSession.Groups)
		}
	}
}