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.

Insecure IPC: Missing Sender Verification

Objective-C
Swift

Abstract

The application fails to verify the sender of a URL-based Inter-Procedure Communication (IPC) call.

Explanation

When a third party application or webview uses a URL to communicate with your application, the receiving application should verify that the sender matches an allow list of applications that are expected to communicate with it. The receiving application has the option to verify the origin of the calling URL using the UIApplicationDelegate application:openURL:options: or UIApplicationDelegate application:openURL:sourceApplication:annotation: delegate methods.

Example 1: The following implementation of the UIApplicationDelegate application:openURL:options: delegate method fails to verify the sender of the IPC call and just processes the calling URL:


    - (BOOL)application:(UIApplication *)app openURL:(NSURL *)url options:(NSDictionary<NSString *,id> *)options {
        NSString *theQuery = [[url query] stringByRemovingPercentEncoding:NSUTF8StringEncoding];
        NSArray *chunks = [theQuery componentsSeparatedByString:@"&"];
        for (NSString* chunk in chunks) {
            NSArray *keyval = [chunk componentsSeparatedByString:@"="]; NSString *key = [keyval objectAtIndex:0];
            NSString *value = [keyval objectAtIndex:1];
            // Do something with your key and value
        }
        return YES;
    }

References

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

[2] UIApplicationDelegate Apple

[3] Standards Mapping - Common Weakness Enumeration CWE ID 501, CWE ID 939

[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [25] CWE ID 862

[5] Standards Mapping - Common Weakness Enumeration Top 25 2021 [18] CWE ID 862

[6] Standards Mapping - Common Weakness Enumeration Top 25 2022 [16] CWE ID 862

[7] Standards Mapping - Common Weakness Enumeration Top 25 2023 [11] CWE ID 862

[8] Standards Mapping - Common Weakness Enumeration Top 25 2024 [9] CWE ID 862

[9] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-001084, CCI-002754

[10] Standards Mapping - FIPS200 SI

[11] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data

[12] Standards Mapping - NIST Special Publication 800-53 Revision 4 SC-3 Security Function Isolation (P1), SI-10 Information Input Validation (P1)

[13] Standards Mapping - NIST Special Publication 800-53 Revision 5 SC-3 Security Function Isolation, SI-10 Information Input Validation

[14] Standards Mapping - OWASP Application Security Verification Standard 4.0 4.1.3 General Access Control Design (L1 L2 L3), 4.1.5 General Access Control Design (L1 L2 L3), 4.2.1 Operation Level Access Control (L1 L2 L3), 13.1.4 Generic Web Service Security Verification Requirements (L2 L3)

[15] Standards Mapping - OWASP Mobile 2014 M8 Security Decisions Via Untrusted Inputs

[16] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation

[17] Standards Mapping - OWASP Mobile Application Security Verification Standard 2.0 MASVS-CODE-4, MASVS-PLATFORM-1

[18] Standards Mapping - OWASP Top 10 2004 A1 Unvalidated Input

[19] Standards Mapping - OWASP Top 10 2021 A04 Insecure Design

[20] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.1

[21] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1

[22] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I

[23] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I

[24] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I

[25] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I

[26] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I

[27] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I

[28] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I

[29] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[30] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[31] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[32] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[33] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[34] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[35] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[36] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002360 CAT II, APSC-DV-002560 CAT I

[44] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)

desc.structural.objc.insecure_ipc_missing_sender_verification

Abstract

The application fails to verify the sender of a URL-based Inter-Procedure Communication (IPC) call.

Explanation

When a third party application or wewbview uses a URL to communicate with your application, the receiving application should verify that the sender matches an allow list of applications that are expected to communicate with it. The receiving application has the option to verify the origin of the calling URL using the UIApplicationDelegate application:openURL:options: or UIApplicationDelegate application:openURL:sourceApplication:annotation: delegate methods.

Example 1: The following implementation of the UIApplicationDelegate application:openURL:options: delegate method fails to verify the sender of the IPC call and just processes the calling URL:


    func application(app: UIApplication, openURL url: NSURL, options: [String : AnyObject]) -> Bool {
        return processCall(url)
    }