Threat actors affiliated with a ransomware strain known as Play are leveraging a never-before-seen exploit chain that bypasses blocking rules for ProxyNotShell flaws in Microsoft Exchange Server to achieve remote code execution (RCE) through Outlook Web Access (OWA).
“The new exploit method bypasses URL rewrite mitigations for the Autodiscover endpoint,” CrowdStrike researchers Brian Pitchford, Erik Iker, and Nicolas Zilio said in a technical write-up published Tuesday.
