Fragment Injection
Description
The application is vulnerable to Fragment Injection caused either by an unsafe implementation of PreferenceActivity or an insecure configuration of isValidFragment.
Impact
Use malicious fragments to exploit different vulnerabilities.
Recommendation
- Set the attribute exported to false to avoid the attempt of foreign applications to exploit the vulnerability.
- Ensure the application is running with targetSdkVersion higher than 19.
- Set a whitelist of trusted fragments and validate them through the implementation of isValidFragment.
Threat
Authenticated attacker from the Internet.
Expected Remediation Time
⌚ 120 minutes.
Score
Default score using CVSS 3.1. It may change depending on the context of the src.
Base
- Attack vector: N
- Attack complexity: H
- Privileges required: L
- User interaction: N
- Scope: U
- Confidentiality: N
- Integrity: L
- Availability: N
Temporal
- Exploit code maturity: P
- Remediation level: O
- Report confidence: R
Result
- Vector string: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:R
- Score:
- Base: 3.1
- Temporal: 2.7
- Severity:
- Base: Low
- Temporal: Low
Score 4.0
Default score using CVSS 4.0. It may change depending on the context of the src.
Base 4.0
- Attack vector: N
- Attack complexity: H
- Attack Requirements: N
- Privileges required: L
- User interaction: N
- Confidentiality (VC): N
- Integrity (VI): L
- Availability (VA): N
- Confidentiality (SC): N
- Integrity (SI): N
- Availability (SA): N
Threat 4.0
- Exploit maturity: P
Result 4.0
- Vector string: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
- Score:
- CVSS-BT: 1.3
- Severity:
- CVSS-BT: Low
Compliant code
Implement a check for every fragment introduced to the application
public boolean isValidFragment(String fragmentName) {
return MyFragment.class.getName().equals(fragmentName);
}
Non compliant code
There are unverified inputs that are used to put fragments into the application
@Override
String initialFragment = getIntent().getStringExtra(EXTRA_SHOW_FRAGMENT);
Bundle initialArguments = getIntent().getBundleExtra(EXTRA_SHOW_FRAGMENT_ARGUMENTS);
if (savedInstanceState != null) {
//Handle Exception
} else {
if (initialFragment != null && mSinglePane) {
// Add Fragment to the application
}
}
}
Requirements
Fixes
