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
Exploited in the Wild
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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
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####.

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

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

Technical Analysis