CVE-2021-0695: Medium Vulnerability in Google Android

CVE-2021-0695 is a vulnerability in the Android kernel, specifically in the function get_sock_stat of xt_qtaguid.c. This vulnerability allows for a possible out of bounds read due to a use after free condition. With a CVSS score of 5.5, categorized as medium severity, this vulnerability requires user execution privileges but does not necessitate user interaction for exploitation. The risk to organizations includes potential local information disclosure, making it crucial for defenders to address this vulnerability promptly.

The vulnerability was published on October 6, 2021, and has been classified under CWE-416, indicating a use after free issue. Given the nature of this vulnerability and its implications, organizations should prioritize patching immediately.

Currently, there is no known public exploit available, and the vulnerability has not been included in the Known Exploited Vulnerabilities (KEV) catalog. However, given the potential impact, organizations should remain vigilant and ensure that they implement necessary mitigations.

The urgency for remediation cannot be overstated, as the risks associated with this vulnerability could lead to significant data exposure if left unaddressed. Organizations are encouraged to stay updated with vendor advisories and ensure their systems are patched accordingly.

For continuous security, organizations might consider engaging in regular penetration testing to identify and mitigate similar vulnerabilities in the future.

Vulnerability Details

The official description of CVE-2021-0695 states that it allows for a possible out of bounds read due to a use after free in the function get_sock_stat of xt_qtaguid.c. This vulnerability affects the Android kernel and is classified under CWE-416. With a CVSS 3.1 score of 5.5, it is essential for organizations to understand the severity of this issue.

The attack vector is local, requiring low attack complexity and low privileges, with no user interaction needed. The confidentiality impact is high, while integrity and availability are not affected. Organizations should take this vulnerability seriously, as it could lead to significant risks if exploited.

Technical Analysis

The root cause of CVE-2021-0695 lies in the improper handling of memory management in the function get_sock_stat. This leads to a use after free scenario, where the memory previously allocated is accessed after it has been freed. The attack vector is local, indicating that the vulnerability can only be exploited by an authenticated user on the affected device.

The attack complexity is low, meaning that an attacker could exploit the vulnerability without extensive knowledge or advanced techniques. The prerequisites for exploitation are low privileges, as the user executing the attack does not require administrative rights.

User interaction is not required to exploit this vulnerability, increasing the risk of its exploitation in real-world scenarios. The confidentiality impact is high, indicating that sensitive data could be exposed, while integrity and availability impacts are not applicable.

Risk & Impact Analysis

The real-world deployment risk associated with CVE-2021-0695 is significant, as potential local information disclosure could lead to unauthorized access to sensitive data. This vulnerability could be exploited by malicious actors to gain insights into user activities or system configurations, leading to further attacks.

Organizations should be aware of the urgency of addressing this vulnerability based on its CVSS score and the potential blast radius. The absence of known public exploits does not diminish the threat, as attackers may still attempt to exploit this vulnerability using other means.

Given its classification as a medium severity vulnerability, organizations should address it in their priority patch cycle to mitigate the risks associated with local information disclosure.

Exploitation Status

Affected Versions

The affected versions include all versions of the Android kernel prior to the vendor patch. Organizations using Google Android should ensure they update their systems to mitigate this vulnerability.

Mitigation & Remediation

To mitigate CVE-2021-0695, organizations should apply the latest patches provided by Google for the Android kernel. Regular updates help ensure that vulnerabilities are addressed promptly.

In cases where immediate patching is not possible, organizations should consider implementing network controls to limit the exposure of affected devices. Additionally, employing security monitoring can help detect any unusual activities that may indicate exploitation attempts.

For a comprehensive approach to security, organizations may explore penetration testing services to identify vulnerabilities in their systems.

Detection Guidance

Organizations should monitor logs for indicators of exploitation attempts related to CVE-2021-0695. This may include unusual access patterns or attempts to exploit local vulnerabilities.

Behavioral anomalies in user activity can also serve as a signal for potential exploitation. Implementing network signatures that detect anomalous behavior can help organizations respond to potential threats quickly.

AppSecure Threat Intelligence Insight

CVE-2021-0695 demonstrates the ongoing challenges of maintaining secure coding practices in the Android kernel. The vulnerability exemplifies how memory management issues can lead to significant security risks.

Security teams should learn from this incident and implement robust testing frameworks to catch such vulnerabilities early in the development lifecycle. Continuous security assessments are essential as the attack surface evolves.

For a deeper understanding of handling vulnerabilities similar to CVE-2021-0695, organizations can refer to our penetration testing methodology blog for best practices.

Additionally, insights from ongoing vulnerability research and threat intelligence can empower organizations to better prepare for and respond to similar vulnerabilities in the future.