(THIS CODING RULE OR GUIDELINE IS UNDER CONSTRUCTION)

 Chin, et al., [Chin 2011] says: "If a Service is exported and not protected with strong permissions, then any application can start and bind to the Service. Depending on the duties of a particular Service, it may leak information or perform unauthorized tasks. Services sometimes maintain singleton application state, which could be corrupted."

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This compliant solution shows the permissions set in the manifest that prevent the service shown in the noncompliant code example from being started by an inappropriate application:

Disclaimer: the code below is preliminary. and modifed from an answer from stackoverflow.

//base app manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>
    <permission android:name="customPermission" android:protectionLevel="dangerous" ...></permission>
    <application ...>
        <activity
            android:permission="customPermission"
            ... >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter >
                <action android:name="package_name.MyAction" />
                <category android:name="android.intent.category.DEFAULT" />                
            </intent-filter>
        </activity>
    </application>
</manifest>
 
//apps who wish to use base app manifest
<manifest ...>
<uses-permission
     android:name="customPermission"
     android:maxSdkVersion=.. />
...
</manifest>
 
//in the activities of these apps where we want to use the base-app's activity under protection
Intent in = new Intent();
in.setAction("package_name.MyAction");
in.addCategory("android.intent.category.DEFAULT");
startActivity(in);

The above is a general example on how to use custom permission. There are also other types of permissions aside from "dangerous" .  Please note that the order the  of how the apps are started also affect how permission works [Murphy 2011].

Risk Assessment

Failing to protect an exported service with strong permissions may lead to sensitive data being revealed or to denial of service.

Automated Detection

Automatic detection of an exported service is straightforward. It is not feasible to automatically determine whether appropriate permissions have been set in the manifest.

Related Vulnerabilities

• CVE-2017-12816 In Kaspersky Internet Security for Android 11.12.4.1622, some of application exports activities have weak permissions
• CVE-2016-10135 Multiple LG Android Mobile Devices Multiple Security Bypass Vulnerabilities
  

Related Guidelines

Bibliography

TODO: edit code section, add bibliography

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