Kingdom: Security Features

Software security is not security software. Here we're concerned with topics like authentication, access control, confidentiality, cryptography, and privilege management.

Privacy Violation: Incomplete Credential Removal

Objective-C
Swift

Abstract

The identified method removes an NSURLCredential instance locally but fails to remove the copy stored on other devices and iCloud.

Explanation

When creating an instance of NSURLCredential containing the user's credentials in the form or a username/password pair or a client certificate, a persistence attribute needs to be defined. The possible values are:

- NSURLCredentialPersistenceNone: Credential should not be stored.
- NSURLCredentialPersistenceForSession: Credential should be stored only for this session.
- NSURLCredentialPersistencePermanent: Credential should be stored in the Keychain.
- NSURLCredentialPersistenceSynchronizable: Credential should be stored permanently in the Keychain, and in addition should be distributed to other devices based on the owning AppleID.

Since NSURLCredentialPersistenceSynchronizable credentials are distributed to other devices and iCloud, failing to completely remove the credential from all places will leave instances that could be leaked.

Example 1: The following snippet of code creates a synchronizable credential, uses it and then removes it locally but fails to remove it from other devices and iCloud:


    ...
    // Create the credential
	NSURLCredential *credential = [NSURLCredential credentialWithUser:user password:password persistence:NSURLCredentialPersistenceSynchronizable]; 
    NSURLCredentialStorage *shared = [NSURLCredentialStorage sharedCredentialStorage];
    [shared setDefaultCredential:credential forProtectionSpace:protectionSpace]; 

    // Use the credential as needed
    ...

    // Removes the credential
    [shared removeCredential:credential forProtectionSpace:protectionSpace];
    ...

References

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

[2] Standards Mapping - CIS Azure Kubernetes Service Benchmark 4

[3] Standards Mapping - CIS Amazon Elastic Kubernetes Service Benchmark 4

[4] Standards Mapping - CIS Amazon Web Services Foundations Benchmark 3

[5] Standards Mapping - CIS Google Kubernetes Engine Benchmark normal

[6] Standards Mapping - Common Weakness Enumeration CWE ID 359

[7] Standards Mapping - Common Weakness Enumeration Top 25 2019 [4] CWE ID 200

[8] Standards Mapping - Common Weakness Enumeration Top 25 2020 [7] CWE ID 200

[9] Standards Mapping - Common Weakness Enumeration Top 25 2021 [20] CWE ID 200

[10] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002475

[11] Standards Mapping - General Data Protection Regulation (GDPR) Privacy Violation

[12] Standards Mapping - NIST Special Publication 800-53 Revision 4 AC-4 Information Flow Enforcement (P1), SC-28 Protection of Information at Rest (P1)

[13] Standards Mapping - NIST Special Publication 800-53 Revision 5 AC-4 Information Flow Enforcement, SC-28 Protection of Information at Rest

[14] Standards Mapping - OWASP Top 10 2004 A8 Insecure Storage

[15] Standards Mapping - OWASP Top 10 2007 A6 Information Leakage and Improper Error Handling

[16] Standards Mapping - OWASP Top 10 2013 A6 Sensitive Data Exposure

[17] Standards Mapping - OWASP Top 10 2017 A3 Sensitive Data Exposure

[18] Standards Mapping - OWASP Top 10 2021 A02 Cryptographic Failures

[19] Standards Mapping - OWASP Application Security Verification Standard 4.0 8.2.2 Client-side Data Protection (L1 L2 L3), 8.3.4 Sensitive Private Data (L1 L2 L3), 10.2.1 Malicious Code Search (L2 L3)

[20] Standards Mapping - OWASP Mobile 2014 M2 Insecure Data Storage

[21] Standards Mapping - OWASP Mobile 2024 M6 Inadequate Privacy Controls

[22] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-STORAGE-1

[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 8.4

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.6, Requirement 8.4

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.5, Requirement 8.4

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.5, Requirement 8.2.1

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.5, Requirement 8.2.1

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.5, Requirement 8.2.1

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 3.2, Requirement 3.4, Requirement 4.2, Requirement 6.5.5, Requirement 8.2.1

[30] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 3.3.1, Requirement 3.5.1, Requirement 4.2.2, Requirement 6.2.4, Requirement 8.3.1

[31] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 3.3 - Sensitive Data Retention, Control Objective 6.1 - Sensitive Data Protection, Control Objective 7 - Use of Cryptography

[32] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 3.3 - Sensitive Data Retention, Control Objective 6.1 - Sensitive Data Protection, Control Objective 7 - Use of Cryptography

[33] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 3.3 - Sensitive Data Retention, Control Objective 6.1 - Sensitive Data Protection, Control Objective 7 - Use of Cryptography

[34] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3210.1 CAT II, APP3310 CAT I, APP3340 CAT I

[35] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3210.1 CAT II, APP3340 CAT I

[36] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3210.1 CAT II, APP3340 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3210.1 CAT II, APP3340 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3210.1 CAT II, APP3340 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3210.1 CAT II, APP3340 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3210.1 CAT II, APP3340 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002340 CAT II

[42] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002340 CAT II

[43] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002340 CAT II

[44] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002340 CAT II

[45] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002340 CAT II

[46] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002340 CAT II

[47] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002340 CAT II

[48] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002340 CAT II

[49] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002340 CAT II

[50] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002340 CAT II

[51] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002340 CAT II

[52] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002340 CAT II

[53] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002340 CAT II

[54] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002340 CAT II

[55] Standards Mapping - Web Application Security Consortium Version 2.00 Information Leakage (WASC-13)

[56] Standards Mapping - Web Application Security Consortium 24 + 2 Information Leakage

desc.structural.objc.privacy_violation_incomplete_credential_removal

Abstract

The identified method removes an NSURLCredential instance locally but fails to remove the copy stored on other devices and iCloud.

Explanation


    ...
    // Create the credential
    let credential = NSURLCredential(user:foo, password:password, persistence:.Synchronizable) 
    let shared = NSURLCredentialStorage.sharedCredentialStorage()
    shared.setCredential(credential, forProtectionSpace:protectionSpace)

    // Use the credential as needed
    ...

    // Removes the credential
    shared.removeCredential(credential, forProtectionSpace:protectionSpace)
    ...