Microsoft’s May 2024 Patch Tuesday Addresses 59 CVEs (CVE-2024-30051, CVE-2024-30040)

CVE-2024-30051 is an EoP vulnerability in the DWM Core Library in Microsoft Windows. It was assigned a CVSSv3 score of 7.8 and is rated as important. Microsoft noted that it was exploited in the wild as a zero-day and was publicly disclosed prior to a patch being available. A local attacker with a presence on a vulnerable system could exploit this vulnerability to gain SYSTEM privileges. Discovery of this flaw is credited to several researchers at Google Threat Analysis Group, Google Mandiant and Kaspersky. It is also credited to Quan Jin of DBAPPSecurity WeBin Lab, who disclosed CVE-2023-36033, another zero-day vulnerability in the DWM Core Library exploited in the wild that was patched in November 2023. Researchers at Kaspersky have linked this zero-day vulnerability to QakBot and other malware.

In addition to CVE-2024-30051, Microsoft patched two other EoP vulnerabilities in the DWM Core Library (CVE-2024-30032, CVE-2024-30035) and an information disclosure vulnerability (CVE-2024-30008). All three flaws were disclosed to Microsoft by Zhang WangJunJie and He YiSheng of the Hillstone Network Security Research Institute.

CVE-2024-30040 is a security feature bypass vulnerability in the MSHTML (Trident) engine in Microsoft Windows that was exploited in the wild as a zero-day. It was assigned a CVSSv3 score of 8.8 and is rated as important. An attacker could exploit this vulnerability by using social engineering tactics via email, social media or instant messaging to convince a target user to open a specially crafted document. Once exploited, an attacker could execute code on the target system. Discovery of this flaw is unattributed.

In 2023, there were eight vulnerabilities patched in MSHTML including three RCEs, four security feature bypass flaws and one EoP* (CVE-2024-32046) that was exploited as a zero-day:

CVE-2024-30046 is a denial of service (DoS) vulnerability affecting multiple versions of Microsoft Visual Studio 2022. It was assigned a CVSSv3 score of 5.9 and is rated important. It is listed as being publicly disclosed prior to a patch being made available. It is rated as “Exploitation Less Likely” according to Microsoft’s Exploitability Index and its Attack Complexity rating is listed as High. This is due to the fact that an attacker would need to “invest time in repeated exploitation attempts” through the sending of “constant or intermittent data” to a targeted system. DoS attacks often require a steady stream of requests in order to overwhelm a target system, so these ratings are expected.

CVE-2024-30044 is a RCE vulnerability in Microsoft SharePoint Server. It was assigned a CVSSv3 score of 8.8 and is rated critical. This vulnerability is rated as “Exploitation More Likely.” However, exploitation of this flaw requires an attacker authenticated to a vulnerable SharePoint Server with Site Owner permissions to perform two steps: 1.) the attacker must upload a specially crafted file to the vulnerable SharePoint Server and 2.) send specially crafted API requests to the SharePoint Server in order to “trigger deserialization of file’s parameters.” Successful exploitation would result in remote code execution “in the context of the SharePoint Server.”