CVE-2021-40486 is a vulnerability that affects certain versions of the Microsoft Windows Print Spooler service. The flaw resides in the way this service handles the Printer Driver Installation Privilege (PDIP) feature, which allows non-administrative users to install printer drivers on the system. Attackers can exploit this vulnerability by running malicious code with elevated privileges, allowing them to take control of affected systems and carry out various malicious activities such as stealing sensitive information, installing malware, and conducting ransomware attacks.
The vulnerability was first reported to Microsoft in June 2021 by researchers from the Chinese cybersecurity firm Sangfor Technologies. Although Microsoft released a security update to address this flaw as part of its July 2021 Patch Tuesday updates, it was later discovered that the fix was not complete and still left systems vulnerable to attack. This prompted Microsoft to release an emergency out-of-band update in early August 2021.
It is important for organizations using Windows Print Spooler service to apply the necessary security updates promptly to mitigate any potential risks associated with this vulnerability. Additionally, organizations are advised to review their security policies and restrict access to critical systems only to trusted personnel to prevent unauthorized installation of printer drivers and reduce the risk of exploitation.