CVE-2021-39621 Explained : Impact and Mitigation

Android devices are impacted by a vulnerability that could allow an attacker to bypass permissions, leading to an elevation of privilege without requiring user interaction.

Understanding CVE-2021-39621

This CVE identifies a security issue in Android devices related to permission handling.

What is CVE-2021-39621?

The vulnerability lies in the LegacyModeSmsHandler.java file, allowing a potential permissions bypass through an unsafe PendingIntent. Exploiting this flaw could result in local privilege escalation, with no user interaction needed.

The Impact of CVE-2021-39621

If exploited, this vulnerability could lead to an elevation of privilege, granting unauthorized access on affected Android versions.

Technical Details of CVE-2021-39621

This section delves into specific technical aspects of the vulnerability.

Vulnerability Description

Type: Elevation of privilege
Description: Unsafe PendingIntent in sendLegacyVoicemailNotification of LegacyModeSmsHandler.java

Affected Systems and Versions

Product: Android
Versions: Android-10, Android-11, Android-12, Android-9

Exploitation Mechanism

The vulnerability can be exploited by utilizing an unsafe PendingIntent in the mentioned Java file to gain elevated privileges.

Mitigation and Prevention

Addressing steps and precautions to mitigate the impact of CVE-2021-39621.

Immediate Steps to Take

Consider restricting app permissions to minimize potential risks.
Update Android devices to the latest available security patches.
Implement least privilege access control mechanisms.

Long-Term Security Practices

Regularly monitor and update security configurations.
Conduct security awareness training to educate users on safe app usage practices.

Patching and Updates

Stay informed about security bulletins and updates from Android to patch known vulnerabilities and enhance device security.