Attacker Value
High
(1 user assessed)
Exploitability
Moderate
(1 user assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

CVE-2020-0646

Disclosure Date: January 14, 2020 •
CVE-2020-0646 CVSS v3 Base Score: 9.8
Exploited in the Wild
Reported by gwillcox-r7
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Description

A remote code execution vulnerability exists when the Microsoft .NET Framework fails to validate input properly, aka ‘.NET Framework Remote Code Execution Injection Vulnerability’.

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1
Ratings
  • Attacker Value
    High
  • Exploitability
    Medium
Common in enterpriseEasy to weaponizeGives privileged accessVulnerable in default configurationAuthenticated
Technical Analysis

The SharePoint WorkFlow component is affected by a vulnerability within .NET which can be abused to run arbitrary code when compiling XOML files. An authenticated user would need to issue an HTTP request with crafted XOML-formatted data (for which there are public examples). The vulnerability was patched for on-premises installations of SharePoint on January 2020.

A correct crafted XOML request will result in extra C# code being written to a temporary file on disk as part of the exploitation process. This is how an OS command is then executed.

Both patched and unpatched systems will return compiler error information in the XML response to the HTTP request. A patched system will have an error stating "Compilation failed. The type name: ... is not a valid language-independent type name.". Malformed requests will include relevant information in the compiler error text, which is usually a character escaping issue. For best results escape all characters that are non-alphanumeric as unicode like \u####.

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CVSS V3 Severity and Metrics
Base Score:
9.8 Critical
Impact Score:
5.9
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows 7 for 32-bit Systems Service Pack 1
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows 7 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows 8.1 for 32-bit systems
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows 8.1 for x64-based systems
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows RT 8.1
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2008 R2 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2012
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2012 (Server Core installation)
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2012 R2
Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 Windows Server 2012 R2 (Server Core installation)
Microsoft .NET Framework 4.6.2/4.7/4.7.1/4.7.2 Windows 10 Version 1607 for 32-bit Systems
Microsoft .NET Framework 4.8 on Windows 10 Version 1803 for 32-bit Systems
Microsoft .NET Framework 4.8 on Windows 10 Version 1803 for x64-based Systems
Microsoft .NET Framework 4.8 on Windows Server, version 1803 (Server Core Installation)
Microsoft .NET Framework 4.8 on Windows 10 Version 1709 for 32-bit Systems
Microsoft .NET Framework 4.8 on Windows 10 Version 1709 for x64-based Systems
Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for 32-bit Systems
Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems
Microsoft .NET Framework 4.8 on Windows Server 2016
Microsoft .NET Framework 4.8 on Windows Server 2016 (Server Core installation)
Microsoft .NET Framework 4.8 on Windows 7 for 32-bit Systems Service Pack 1
Microsoft .NET Framework 4.8 on Windows 7 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.8 on Windows 8.1 for 32-bit systems
Microsoft .NET Framework 4.8 on Windows 8.1 for x64-based systems
Microsoft .NET Framework 4.8 on Windows RT 8.1
Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .NET Framework 4.8 on Windows Server 2012
Microsoft .NET Framework 4.8 on Windows Server 2012 (Server Core installation)
Microsoft .NET Framework 4.8 on Windows Server 2012 R2
Microsoft .NET Framework 4.8 on Windows Server 2012 R2 (Server Core installation)
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1809 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server 2019 (Server Core installation)
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1903 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1903 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server, version 1903 (Server Core installation) 1903
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019 (Server Core installation)
Microsoft .NET Framework 4.6 Windows Server 2008 for 32-bit Systems Service Pack 2
Microsoft .NET Framework 4.6 Windows Server 2008 for x64-based Systems Service Pack 2
Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for 32-bit Systems Service Pack 2
Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for Itanium-Based Systems Service Pack 2
Microsoft .NET Framework 3.0 Service Pack 2 on Windows Server 2008 for x64-based Systems Service Pack 2
Microsoft .NET Framework 3.5 Windows 10 Version 1607 for 32-bit Systems
Microsoft .NET Framework 3.5 Windows 8.1 for 32-bit systems
Microsoft .NET Framework 3.5 Windows 8.1 for x64-based systems
Microsoft .NET Framework 3.5 Windows Server 2012
Microsoft .NET Framework 3.5 Windows Server 2012 (Server Core installation)
Microsoft .NET Framework 3.5 Windows Server 2012 R2
Microsoft .NET Framework 3.5 Windows Server 2012 R2 (Server Core installation)
Microsoft .NET Framework 3.5.1 Windows 7 for 32-bit Systems Service Pack 1
Microsoft .NET Framework 3.5.1 Windows 7 for x64-based Systems Service Pack 1
Microsoft .NET Framework 3.5.1 Windows Server 2008 R2 for Itanium-Based Systems Service Pack 1
Microsoft .NET Framework 3.5.1 Windows Server 2008 R2 for x64-based Systems Service Pack 1
Microsoft .NET Framework 3.5.1 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .NET Framework 4.5.2 Windows 7 for 32-bit Systems Service Pack 1
Microsoft .NET Framework 4.5.2 Windows 7 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.5.2 Windows 8.1 for 32-bit systems
Microsoft .NET Framework 4.5.2 Windows 8.1 for x64-based systems
Microsoft .NET Framework 4.5.2 Windows RT 8.1
Microsoft .NET Framework 4.5.2 Windows Server 2008 for 32-bit Systems Service Pack 2
Microsoft .NET Framework 4.5.2 Windows Server 2008 for x64-based Systems Service Pack 2
Microsoft .NET Framework 4.5.2 Windows Server 2008 R2 for x64-based Systems Service Pack 1
Microsoft .NET Framework 4.5.2 Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Microsoft .NET Framework 4.5.2 Windows Server 2012
Microsoft .NET Framework 4.5.2 Windows Server 2012 (Server Core installation)
Microsoft .NET Framework 4.5.2 Windows Server 2012 R2
Microsoft .NET Framework 4.5.2 Windows Server 2012 R2 (Server Core installation)
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1909 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.8 on Windows Server, version 1909 (Server Core installation)
Microsoft .NET Framework 3.5 AND 4.8 on Windows 10 Version 1909 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server, version 1803 (Server Core Installation)
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1803 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016 (Server Core installation)
Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.7.1/4.7.2 on Windows 10 Version 1709 for 32-bit Systems
Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows 10 Version 1607 for x64-based Systems
Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2016
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
exploit/windows/http/sharepoint_workflows_xoml
Reporter
Unknown

Vendors

  • microsoft

Products

  • .net framework 3.0,
  • .net framework 3.5,
  • .net framework 3.5.1,
  • .net framework 4.5.2,
  • .net framework 4.6,
  • .net framework 4.6.1,
  • .net framework 4.6.2,
  • .net framework 4.7,
  • .net framework 4.7.1,
  • .net framework 4.7.2,
  • .net framework 4.8

Exploited in the Wild

Reported by:

Additional Info

Authenticated
Unknown
Exploitable
Unknown
Reliability
Unknown
Stability
Unknown
Available Mitigations
Unknown
Shelf Life
Unknown
Userbase/Installbase
Unknown
Patch Effectiveness
Unknown
Technical Analysis