CVE-2020-1069 in SharePoint Enterprise Server
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft SharePoint Server when it fails to properly identify and filter unsafe ASP.Net web controls, aka 'Microsoft SharePoint Server Remote Code Execution Vulnerability'.
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Analysis
by VulDB Data Team • 10/16/2020
This vulnerability represents a critical remote code execution flaw in Microsoft SharePoint Server that stems from inadequate validation of ASP.NET web controls within the application's web interface. The vulnerability specifically manifests when SharePoint Server fails to properly sanitize or filter potentially dangerous web controls that could be exploited by attackers to execute arbitrary code on the affected system. This issue affects multiple versions of Microsoft SharePoint Server including 2016 and 2019, creating a significant attack surface that could allow malicious actors to gain unauthorized access to sensitive organizational data and systems.
The technical root cause of this vulnerability lies in the improper handling of user input within SharePoint's web control rendering pipeline. When SharePoint processes web controls submitted through web forms or other user interaction mechanisms, it does not sufficiently validate or sanitize the control definitions to prevent the inclusion of dangerous elements that could be leveraged for code execution. This flaw aligns with CWE-79 which describes improper neutralization of input during web page generation, specifically in the context of ASP.NET web controls. The vulnerability allows attackers to inject malicious web controls that bypass the normal security restrictions, potentially enabling full system compromise through remote code execution.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the capability to establish persistent access to SharePoint environments. Successful exploitation could enable threat actors to deploy malicious code, escalate privileges, access sensitive documents, and potentially use the compromised SharePoint server as a pivot point for attacking other systems within the network. The vulnerability affects organizations that rely on SharePoint for document management, collaboration, and enterprise content management, making it particularly dangerous for businesses with extensive SharePoint deployments. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: PowerShell) and T1078 (Valid Accounts) as attackers could use the executed code to establish persistence and move laterally within the network.
Mitigation strategies for this vulnerability should include immediate application of Microsoft security patches and updates, which address the underlying validation issues in SharePoint's web control handling mechanisms. Organizations should also implement network segmentation to limit access to SharePoint servers, deploy web application firewalls to monitor and filter suspicious traffic, and conduct regular security assessments to identify potential exploitation attempts. Additionally, administrators should review and harden SharePoint configurations to minimize the attack surface, disable unnecessary web controls, and implement strict input validation policies. The vulnerability also underscores the importance of regular security updates and vulnerability management programs that can quickly address similar issues across the organization's Microsoft products and services.