hello, I'm writing to seek clarification on Apple account security, particularly regarding potential risks of compromise, implemented safeguards, and residual risks with corresponding mitigation strategies. We would appreciate your insights on the following specific points: iCloud Keychain Access: Is an Apple ID login strictly required to access iCloud Keychain? We understand that a compromise of iCloud Keychain is unlikely unless a malicious actor successfully takes over the legitimate user's Apple ID. Is this understanding correct? Passkey Theft Methods and Protections: What are the conceivable methods a malicious actor might employ to steal a legitimate user's passkey, and how are these attempts protected against? Impact of Apple ID Compromise on Passkeys: If a malicious actor successfully compromises a legitimate user's Apple ID, is it accurate to assume that the legitimate user's passkeys would then synchronize to the attacker's device, potentially allowing them to log in using their own biometrics? Authorization Flow on Legitimate User's Device: Could you please detail the authorization flow that occurs on the legitimate user's device? We are particularly interested in the types of authentication involved and the conditions under which they are triggered. Detection and Additional Authentication for Unauthorized Login: How are attempts to log in to an Apple ID from an unrecognized device or browser detected, and what additional authentication steps are implemented in such scenarios? Thank you for your time and assistance in addressing these important security questions.

PLATFORM AND VERSION iOS Development environment: Xcode 26.2, macOS x Run-time configuration: iOS The issue does not seem to be limited to a specific version. DESCRIPTION OF PROBLEM We are reaching out to request in-depth technical assistance regarding an intermittent issue with Sign in with Apple implementation in our application. [Technical Status] We have confirmed that our technical implementation is correct. All necessary code and Xcode Capabilities are properly configured, and the service is working perfectly for the vast majority of our users. However, a small subset of users is consistently encountering "Unknown" Error (Error Code 1000), which prevents them from logging in entirely. [Identified Scenario] Currently, the only reproducible case we have found involves Child Accounts (protected accounts) under Family Sharing, specifically when the user's age is set below the regional requirement for a standalone Apple ID. However, we are receiving reports from other users who do not seem to fall into this category. [Requests for Clarification] To resolve this issue and support our users, we would like to obtain clear answers to the following questions: Root Cause: Why does Error 1000 occur specifically for a small number of users while the service works for most others? Other Scenarios: Are there any known cases or conditions other than the "Child Account" age restriction that trigger this specific error? Account-side Issues: If our code and configurations are verified to be correct, should we conclude that this is an issue specific to the individual's Apple ID/Account status? If so, could you provide a troubleshooting guide or official recommendation that we can share with these users to help them resolve their account-related issues? We are committed to providing a seamless authentication experience and would appreciate your expert insight into these edge cases. Thank you for your support. - (void) quickLogin:(uint)requestId withNonce:(NSString *)nonce andState:(NSString *)state { #if AUTHENTICATION_SERVICES_AVAILABLE if (@available(iOS 13.0, tvOS 13.0, macOS 10.15, *)) { ASAuthorizationAppleIDRequest *appleIDRequest = [[self appleIdProvider] createRequest]; [appleIDRequest setNonce:nonce]; [appleIDRequest setState:state]; ASAuthorizationPasswordRequest *keychainRequest = [[self passwordProvider] createRequest]; ASAuthorizationController *authorizationController = [[ASAuthorizationController alloc] initWithAuthorizationRequests:@[appleIDRequest, keychainRequest]]; [self performAuthorizationRequestsForController:authorizationController withRequestId:requestId]; } else { [self sendsLoginResponseInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; } #else [self sendsLoginResponseInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; #endif } - (void) loginWithAppleId:(uint)requestId withOptions:(AppleAuthManagerLoginOptions)options nonce:(NSString *)nonce andState:(NSString *)state { #if AUTHENTICATION_SERVICES_AVAILABLE if (@available(iOS 13.0, tvOS 13.0, macOS 10.15, *)) { ASAuthorizationAppleIDRequest *request = [[self appleIdProvider] createRequest]; NSMutableArray *scopes = [NSMutableArray array]; if (options & AppleAuthManagerIncludeName) [scopes addObject:ASAuthorizationScopeFullName]; if (options & AppleAuthManagerIncludeEmail) [scopes addObject:ASAuthorizationScopeEmail]; [request setRequestedScopes:[scopes copy]]; [request setNonce:nonce]; [request setState:state]; ASAuthorizationController *authorizationController = [[ASAuthorizationController alloc] initWithAuthorizationRequests:@[request]]; [self performAuthorizationRequestsForController:authorizationController withRequestId:requestId]; } else { [self sendsLoginResponseInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; } #else [self sendsLoginResponseInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; #endif } - (void) getCredentialStateForUser:(NSString *)userId withRequestId:(uint)requestId { #if AUTHENTICATION_SERVICES_AVAILABLE if (@available(iOS 13.0, tvOS 13.0, macOS 10.15, *)) { [[self appleIdProvider] getCredentialStateForUserID:userId completion:^(ASAuthorizationAppleIDProviderCredentialState credentialState, NSError * _Nullable error) { NSNumber *credentialStateNumber = nil; NSDictionary *errorDictionary = nil; if (error) errorDictionary = [AppleAuthSerializer dictionaryForNSError:error]; else credentialStateNumber = @(credentialState); NSDictionary *responseDictionary = [AppleAuthSerializer credentialResponseDictionaryForCredentialState:credentialStateNumber errorDictionary:errorDictionary]; [self sendNativeMessageForDictionary:responseDictionary forRequestId:requestId]; }]; } else { [self sendsCredentialStatusInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; } #else [self sendsCredentialStatusInternalErrorWithCode:-100 andMessage:@"Native AppleAuth is only available from iOS 13.0" forRequestWithId:requestId]; #endif }

I am researching URL preview functionality. https://sec-research.invalid/poc"onmouseover="alert(document.domain) Can someone verify on iOS 17?

I am not able to use Feedback because the app can not reset my password.

We are integrating Sign in with Apple for our web application and have been stuck on an invalid_client error during the token exchange step. The Problem The authorization step works fine — the user authenticates on Apple's page and a valid authorization code is returned to our callback URL. However, when we exchange that code at https://appleid.apple.com/auth/token, it returns: {"error": "invalid_client"} The Puzzling Part When we send a dummy/expired authorization code with the exact same client_id and client_secret, Apple returns: {"error": "invalid_grant", "error_description": "The code has expired or has been revoked."} This confirms that our client credentials (client_id + client_secret JWT) are valid and accepted by Apple. The invalid_client error only occurs when a real, freshly-issued authorization code is used. Configuration Service ID configured with Sign in with Apple enabled Primary App ID with Sign in with Apple capability enabled Domain verified, Return URL registered Key created with Sign in with Apple enabled, linked to the correct Primary App ID Client Secret JWT Generated per Apple's documentation: Header: alg: ES256, kid set to our Key ID Claims: iss: Team ID iat: current timestamp exp: iat + 6 months (within Apple's limit) aud: https://appleid.apple.com sub: Service ID (matches the client_id used in authorization) Signed with: the .p8 private key associated with the Key Token Exchange Request POST https://appleid.apple.com/auth/tokenContent-Type: application/x-www-form-urlencodedclient_id=client_secret=code=grant_type=authorization_coderedirect_uri= What We've Tried Standalone test endpoint — built a minimal endpoint (no framework) that does the token exchange via server-side curl. Same invalid_client. Multiple Service IDs — created and tried 3 different Service IDs. All produce the same error with real codes. Multiple Keys — tried 2 different keys. Same error. Verified redirect_uri matches exactly between the authorization request and token request. Verified client_id matches exactly between the authorization URL and token request. Used client_secret_post (credentials in body, not Basic auth header). Freshness — code is used immediately upon receipt (within seconds), well before the 5-minute expiry. Filed a Developer Support case — was directed to Forums. Summary Scenario code Result Dummy/expired code abc123 invalid_grant (credentials accepted) Real fresh code from Apple callback invalid_client This pattern suggests something goes wrong specifically when Apple validates the authorization code against the client — even though the client credentials themselves are accepted in isolation. Has anyone encountered this behavior? Is there a known configuration issue that could cause invalid_client only with valid authorization codes? Any guidance would be greatly appreciated.