CVE-2021-25352 in Bixby Voice
Summary
by MITRE • 03/25/2021
Using PendingIntent with implicit intent in Bixby Voice prior to version 3.0.52.14 allows attackers to execute privileged action by hijacking and modifying the intent.
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Analysis
by VulDB Data Team • 04/05/2021
The vulnerability identified as CVE-2021-25352 represents a critical security flaw in Samsung's Bixby Voice application prior to version 3.0.52.14. This issue stems from the improper handling of PendingIntent objects with implicit intents, creating a pathway for malicious actors to escalate privileges and execute unauthorized actions within the device's security boundaries. The vulnerability specifically affects the Android-based smart home and voice assistant functionalities that Samsung integrated into their mobile devices.
The technical flaw manifests when the Bixby Voice application creates PendingIntent objects that reference implicit intents rather than explicit ones. Implicit intents do not specify a particular component to handle the request, instead relying on the Android system to resolve the appropriate application based on intent filters. When these PendingIntent objects are used in conjunction with vulnerable system components, attackers can manipulate the intent resolution process to redirect execution to malicious applications or components. This vulnerability falls under the CWE-829 category of "Inclusion of Functionality from Untrusted Control Sphere," as it allows external entities to influence the execution flow of privileged system components through improper intent handling.
The operational impact of this vulnerability is significant as it enables attackers to perform privileged actions that should normally be restricted to authorized applications. An attacker could potentially hijack the intent flow to execute system-level commands, modify device settings, access sensitive data, or even install malicious applications without user consent. The exploitation requires a malicious application to be installed on the device, but once present, it can leverage the PendingIntent vulnerability to gain elevated privileges and execute actions that bypass normal Android security controls. This represents a classic privilege escalation vector that aligns with ATT&CK technique T1068 for "Exploitation for Privilege Escalation" and T1548.002 for "Abuse Elevation Control Mechanism: Bypass User Account Control."
The vulnerability demonstrates poor security practices in intent handling and PendingIntent creation within the Bixby Voice application. Proper implementation should have utilized explicit intents that directly reference target components, eliminating the possibility of intent hijacking. Additionally, the application should have implemented proper permission checks and validation mechanisms to prevent unauthorized intent modification. The affected version range indicates that Samsung had not adequately addressed this security gap in their codebase prior to the 3.0.52.14 update. Organizations should ensure that all devices running affected versions of Bixby Voice are updated immediately to mitigate this risk. The vulnerability also highlights the importance of secure coding practices in mobile applications and the need for comprehensive security testing of intent handling mechanisms. This issue serves as a reminder that voice assistant applications, which often have broad system access privileges, require particular attention to security considerations when handling inter-process communication and intent-based operations.