Microsoft’s August 2023 Patch Tuesday fixed eighty-seven (87) vulnerabilities, including six (6) critical remote code execution (RCE) flaws. There are two (2) actively exploited zero-day vulnerabilities, tracked as CVE-2023-36884 and CVE-2023-38180, which are an RCE flaw and a DoS flaw, respectively. The first zero-day exists in Microsoft Office and Windows HTML solutions, allowing attackers to maliciously craft Microsoft Office documents that can bypass the Mark of the Web (MoTW) security feature on vulnerable systems. The exploitation of this flaw was attributed to a threat actor known as RomCom, a Russia-affiliated hacking entity that was confirmed to have targeted Ukraine as well as pro-Ukrainian targets in Eastern Europe and North America. The DoS vulnerability affects .NET applications and Microsoft’s Visual Studio products. At this time there are no technical details about the exploit, but Microsoft states that the “code or technique is not functional in all situations and may require substantial modification by a skilled attacker.” To mitigate these flaws, CTIX analysts recommend all Microsoft users ensure they are running the most recent patched version of the operating system. Details for each vulnerability can be found in the Microsoft August 2023 Patch Tuesday advisory linked below.