CVE-2023-21138 : Security Advisory and Response

In onNullBinding of CallRedirectionProcessor.java, there is a possible long-lived connection due to improper input validation, leading to local escalation of privilege and background activity launches with User execution privileges needed. This vulnerability affects Android versions 11, 12, 12L, and 13, potentially allowing exploitation without user interaction.

Understanding CVE-2023-21138

This section will delve into what CVE-2023-21138 is and the impact it has on affected systems.

What is CVE-2023-21138?

CVE-2023-21138 is a security vulnerability found in the onNullBinding of CallRedirectionProcessor.java in Android. It allows for a long-lived connection that could be exploited for local privilege escalation and unauthorized background activity launches. The vulnerability requires user execution privileges but does not necessitate user interaction for exploitation.

The Impact of CVE-2023-21138

The impact of CVE-2023-21138 is significant, as it opens doors for attackers to elevate their privileges locally on affected Android devices. This can lead to unauthorized actions being carried out in the background without the user's knowledge or consent.

Technical Details of CVE-2023-21138

In this section, we will explore the vulnerability description, affected systems, versions, and the exploitation mechanism of CVE-2023-21138.

Vulnerability Description

The vulnerability in onNullBinding of CallRedirectionProcessor.java in Android allows for a long-lived connection, which can be exploited to escalate privileges locally and launch background activities without user interaction.

Affected Systems and Versions

The vulnerability impacts Android versions 11, 12, 12L, and 13. Users running these versions are at risk of exploitation through this privilege escalation vulnerability.

Exploitation Mechanism

Exploiting CVE-2023-21138 requires a malevolent actor to take advantage of the improper input validation in CallRedirectionProcessor.java to establish a long-lived connection, enabling them to escalate privileges and initiate background activities.

Mitigation and Prevention

To safeguard systems from the risks associated with CVE-2023-21138, immediate steps should be taken, followed by long-term security practices and regularly applying patches and updates.

Immediate Steps to Take

Users are advised to closely monitor security advisories from Android and implement any provided patches or workarounds promptly to mitigate the risks associated with CVE-2023-21138.

Long-Term Security Practices

Maintaining strong security practices, such as restricting access rights, implementing secure coding practices, and conducting regular security assessments, can help prevent similar vulnerabilities from being exploited in the future.

Patching and Updates

Ensuring that systems are up to date with the latest security patches and updates from Android is crucial in addressing and mitigating the risks posed by CVE-2023-21138. Regularly applying patches can help fortify systems against known vulnerabilities and enhance overall security posture.