Security News > 2022 > November > Microsoft fixes ProxyNotShell Exchange zero-days exploited in attacks

Microsoft has released security updates to address two high-severity Microsoft Exchange zero-day vulnerabilities collectively known as ProxyNotShell and exploited in the wild.

Microsoft confirmed they were actively abused in attacks on September 30, saying it was "Aware of limited targeted attacks using the two vulnerabilities to get into users' systems."

The company later released mitigation measures to allow defenders to block incoming ProxyNotShell attacks but had to update the guidance twice after researchers showed that attackers could still bypass them.

"These vulnerabilities affect Exchange Server. Exchange Online customers are already protected from the vulnerabilities addressed in these SUs and do not need to take any action other than updating any Exchange servers in their environment."

Tracked as CVE-2022-41082 and CVE-2022-41040, the two security bugs affect Microsoft Exchange Server 2013, 2016, and 2019.

The ProxyNotShell security flaws can only be exploited remotely by authenticated threat actors in low-complexity attacks that don't require user interaction.

News URL

https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-proxynotshell-exchange-zero-days-exploited-in-attacks/