Kingdom: Encapsulation

Encapsulation is about drawing strong boundaries. In a web browser that might mean ensuring that your mobile code cannot be abused by other mobile code. On the server it might mean differentiation between validated data and unvalidated data, between one user's data and another's, or between data users are allowed to see and data that they are not.

Biometric Authentication: Insufficient Touch ID Protection

Objective-C
Swift

Abstract

The application uses Touch ID to store an item in the Keychain but fails to restrict the valid fingerprints to those available when the Keychain item was stored.

Explanation

Touch ID based authentication can be implemented using the Keychain services by storing an item in the Keychain and setting an access control which requires the user to use their fingerprint to retrieve the item at a later time. The following policies can be used to define how the user will be authenticated using his fingerprint:

- kSecAccessControlUserPresence: Constraint to access with either Touch ID or passcode. Touch ID does not have to be available or enrolled. Item is still accessible by Touch ID even if fingerprints are added or removed.
- kSecAccessControlTouchIDAny: Constraint to access with Touch ID for any enrolled fingerprints. Item is not invalidated if fingerprints are added or removed.
- kSecAccessControlTouchIDCurrentSet: Constraint to access with Touch ID for currently enrolled fingerprints. Item is invalidated if fingerprints are added or removed.

When using Touch ID you should use the kSecAccessControlTouchIDCurrentSet attribute to protect against fingerprints being added or removed in the future.

Example 1: The following code uses the kSecAccessControlTouchIDAny constraint that allows any future-enrolled fingerprint to unlock the Keychain item:


    ...
    SecAccessControlRef sacRef = SecAccessControlCreateWithFlags(kCFAllocatorDefault,
                 kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly,
                 kSecAccessControlTouchIDCurrentSet, 
                 nil);
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    [dict setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id) kSecClass];
    [dict setObject:account forKey:(__bridge id)kSecAttrAccount];
    [dict setObject:service forKey:(__bridge id) kSecAttrService];
    [dict setObject:token forKey:(__bridge id)kSecValueData];
    ...
    [dict setObject:sacRef forKey:(__bridge id)kSecAttrAccessControl];
    [dict setObject:@"Please authenticate using the Touch ID sensor." forKey:(__bridge id)kSecUseOperationPrompt];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        OSStatus status = SecItemAdd((__bridge CFDictionaryRef)dict, nil);
    });
    ...

References

[1] David Thiel iOS Application Security: The Definitive Guide for Hackers and Developers No Starch Press

[2] Integrating Touch ID Into Your iOS Applications Cigital

[3] Don't Touch Me That Way nVisium

[4] SecAccessControlCreateFlags Apple

[5] Standards Mapping - Common Weakness Enumeration CWE ID 287

[6] Standards Mapping - Common Weakness Enumeration Top 25 2019 [13] CWE ID 287

[7] Standards Mapping - Common Weakness Enumeration Top 25 2020 [14] CWE ID 287

[8] Standards Mapping - Common Weakness Enumeration Top 25 2021 [14] CWE ID 287

[9] Standards Mapping - Common Weakness Enumeration Top 25 2022 [14] CWE ID 287

[10] Standards Mapping - Common Weakness Enumeration Top 25 2023 [13] CWE ID 287

[11] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001958

[12] Standards Mapping - FIPS200 CM, SC

[13] Standards Mapping - General Data Protection Regulation (GDPR) Access Violation

[14] Standards Mapping - NIST Special Publication 800-53 Revision 4 IA-3 Device Identification and Authentication (P1)

[15] Standards Mapping - NIST Special Publication 800-53 Revision 5 IA-3 Device Identification and Authentication

[16] Standards Mapping - OWASP Application Security Verification Standard 4.0 2.7.1 Out of Band Verifier Requirements (L1 L2 L3), 2.7.2 Out of Band Verifier Requirements (L1 L2 L3), 2.7.3 Out of Band Verifier Requirements (L1 L2 L3), 2.8.4 Single or Multi Factor One Time Verifier Requirements (L2 L3), 2.8.5 Single or Multi Factor One Time Verifier Requirements (L2 L3), 3.7.1 Defenses Against Session Management Exploits (L1 L2 L3), 9.2.3 Server Communications Security Requirements (L2 L3)

[17] Standards Mapping - OWASP Mobile 2014 M5 Poor Authorization and Authentication

[18] Standards Mapping - OWASP Mobile 2024 M3 Insecure Authentication/Authorization

[19] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-AUTH-1, MASVS-AUTH-2

[20] Standards Mapping - OWASP Top 10 2004 A10 Insecure Configuration Management

[21] Standards Mapping - OWASP Top 10 2007 A9 Insecure Communications

[22] Standards Mapping - OWASP Top 10 2010 A9 Insufficient Transport Layer Protection

[23] Standards Mapping - OWASP Top 10 2021 A07 Identification and Authentication Failures

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 4.1, Requirement 6.5.10

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 4.1, Requirement 6.3.1.4, Requirement 6.5.9

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 4.1, Requirement 6.5.4

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 4.1, Requirement 6.5.4

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 4.1, Requirement 6.5.4

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 4.1, Requirement 6.5.4

[30] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 4.1, Requirement 6.5.4

[31] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 4.2.1, Requirement 6.2.4

[32] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 5.3 - Authentication and Access Control

[33] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 5.3 - Authentication and Access Control

[34] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 5.3 - Authentication and Access Control, Control Objective C.2.1.2 - Web Software Access Controls

[35] Standards Mapping - SANS Top 25 2010 Porous Defenses - CWE ID 311

[36] Standards Mapping - SANS Top 25 2011 Porous Defenses - CWE ID 311

[37] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[38] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[39] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[40] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[41] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[42] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[43] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3250.1 CAT I, APP3250.2 CAT I, APP3250.3 CAT II, APP3250.4 CAT II

[44] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-001650 CAT II

[45] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-001650 CAT II

[46] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-001650 CAT II

[47] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-001650 CAT II

[48] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-001650 CAT II

[49] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-001650 CAT II

[50] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-001650 CAT II

[51] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-001650 CAT II

[52] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-001650 CAT II

[53] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-001650 CAT II

[54] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-001650 CAT II

[55] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-001650 CAT II

[56] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-001650 CAT II

[57] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-001650 CAT II

[58] Standards Mapping - Web Application Security Consortium Version 2.00 Insufficient Authentication (WASC-01)

[59] Standards Mapping - Web Application Security Consortium 24 + 2 Insufficient Authentication

desc.dataflow.objc.biometric_authentication_insufficient_touch_id_protection

Abstract

The application uses Touch ID to store an item in the Keychain but fails to restrict the valid fingerprints to those available when the Keychain item was stored.

Explanation


    ...
    let flags = SecAccessControlCreateWithFlags(kCFAllocatorDefault,
        kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly,
        .TouchIDAny, 
        nil)

    var query = [String : AnyObject]()
    query[kSecClass as String] = kSecClassGenericPassword
    query[kSecAttrService as String] = service as AnyObject?
    query[kSecAttrAccount as String] = account as AnyObject?
    query[kSecValueData as String] = secret as AnyObject?
    ...
    query[kSecAttrAccessControl as String] = sacRef
    query[kSecUseOperationPrompt as String] = "Please authenticate using the Touch ID sensor."

    SecItemAdd(query as CFDictionary, nil)
    ...