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Forwarded from PT SWARM

CVE-2021-26420: Remote Code Execution in Sharepoint via workflow compilation
👤 by The ZDI Research Team

In June of 2021, Microsoft released a patch to correct CVE-2021-26420 – a remote code execution bug in the supported versions of Microsoft SharePoint Server. This bug was reported to the ZDI program by an anonymous researcher and is also known as ZDI-21-755. This blog takes a deeper look at the root cause of this vulnerability.
This vulnerability could be used by an authenticated user to execute arbitrary .NET code on the server in the context and permissions of the service account of a SharePoint web application. For a successful attack, the attacker should have “Manage Lists” permissions on any SharePoint site. By default, any authenticated user can create their own site where they have the necessary permissions.

📝 Contents:
• The Vulnerability
• Proof of Concept
• Achieving Remote Code Execution
• Conclusion

https://www.zerodayinitiative.com/blog/2021/10/5/cve-2021-26420-remote-code-execution-in-sharepoint-via-workflow-compilation
Zero Day Initiative Zero Day Initiative — CVE-2021-26420: Remote Code Execution in SharePoint via Workflow Compilation In June of 2021, Microsoft released a patch to correct CVE-20 21-264 20 – a remote code execution bug in the supported versions of Microsoft SharePoint Server. This bug was reported to the ZDI program by an anonymous researcher and is also known as ZDI…
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