CVE-2021-40728 : Security Advisory and Response

Adobe Acrobat Reader DC version 21.007.20095 (and earlier), 21.007.20096 (and earlier), 20.004.30015 (and earlier), and 17.011.30202 (and earlier) is affected by a use-after-free vulnerability that could lead to arbitrary code execution. This vulnerability requires user interaction to exploit.

Understanding CVE-2021-40728

Adobe Acrobat Reader DC has a use-after-free vulnerability in its processing of the GetURL function, potentially allowing malicious actors to execute arbitrary code.

What is CVE-2021-40728?

The vulnerability in Adobe Acrobat Reader DC could be exploited to execute arbitrary code in the context of the current user. Successful exploitation involves persuading a user to open a malicious file.

The Impact of CVE-2021-40728

The impact of this CVE is assessed with a CVSS base score of 7.8 (High). The confidentiality, integrity, and availability of the affected system are all rated as high.

Technical Details of CVE-2021-40728

Adobe Acrobat Reader DC version 21.007.20095 and earlier, 21.007.20096 and earlier, 20.004.30015 and earlier, and 17.011.30202 and earlier versions are susceptible to this use-after-free vulnerability.

Vulnerability Description

The vulnerability stems from improper handling within the GetURL function, leading to a use-after-free scenario that malicious actors could exploit.

Affected Systems and Versions

Adobe Acrobat Reader DC version 21.007.20095 and earlier
Adobe Acrobat Reader DC version 21.007.20096 and earlier
Adobe Acrobat Reader DC version 20.004.30015 and earlier
Adobe Acrobat Reader DC version 17.011.30202 and earlier

Exploitation Mechanism

The exploitation of this vulnerability requires user interaction, where the victim must be lured into opening a specially crafted malicious file.

Mitigation and Prevention

To address CVE-2021-40728, consider the following mitigation strategies:

Immediate Steps to Take

Update to the latest version of Adobe Acrobat Reader DC immediately.
Exercise caution while opening files from untrusted sources.
Implement security awareness training to educate users about the risks of opening files from unknown origins.

Long-Term Security Practices

Regularly update software and security patches to protect against known vulnerabilities.
Implement robust endpoint protection solutions to detect and prevent such exploitation attempts.

Patching and Updates

Ensure timely installation of security updates released by Adobe for Adobe Acrobat Reader DC to mitigate the risk of exploitation.