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Remote Code Execution in Microsoft SharePoint Server via Deserialization
CVE-2024-38023 is a remote code execution vulnerability in Microsoft SharePoint Server. A remote authenticated attacker with SharePoint permissions at the Site Owner level or higher can exploit the flaw by uploading a specially crafted file and then issuing a specially crafted API request that causes deserialization of parameters from that file. Successful exploitation results in execution of attacker-controlled code in the context of the SharePoint server. The available information indicates the vulnerable condition is tied to unsafe deserialization during SharePoint server-side processing of attacker-supplied file parameters.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation allows arbitrary code execution on the SharePoint server in the security context of the vulnerable SharePoint application environment. This can enable full compromise of the affected SharePoint instance, including execution of malicious server-side logic, access to hosted SharePoint content and application data available to that context, and potential follow-on actions such as persistence or lateral movement depending on the server's privileges and surrounding environment.
If you can’t patch tonight, do this now.
If immediate patching is not possible, reduce exposure by limiting SharePoint Site Owner and higher-privileged roles to only trusted administrators and users, restricting the ability to upload untrusted files where operationally feasible, and limiting access to the affected SharePoint APIs and administrative functionality through network segmentation and access controls. Increased monitoring of SharePoint file uploads and subsequent API activity may help detect exploitation attempts, but no complete mitigation short of vendor remediation is currently available from the provided information.
Patch, then assume compromise.
Apply Microsoft's July 2024 security updates for Microsoft SharePoint Server that address CVE-2024-38023. Priority should be given to vulnerable SharePoint deployments where users with Site Owner or higher privileges exist and can upload content and invoke the affected API functionality.
No public exploits tracked yet. Mallory keeps watching.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.