Microsoft Windows 10 1903/10 1909/Server 1903/Server 1909 SMBv3 Server Message Block SMBGhost input validation

CVSS Meta Temp Score
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CTI Interest Score
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9.8$0-$5k0.00

A vulnerability, which was classified as very critical, was found in Microsoft Windows 10 1903/10 1909/Server 1903/Server 1909 (Operating System). Affected is an unknown part of the component SMBv3. The manipulation as part of a Server Message Block leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests, aka 'Windows SMBv3 Client/Server Remote Code Execution Vulnerability'.

The weakness was disclosed 03/12/2020 as confirmed security update guide (Website). The advisory is shared for download at portal.msrc.microsoft.com. The public release has been coordinated in cooperation with the vendor. This vulnerability is traded as CVE-2020-0796 since 11/04/2019. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are unknown but a public exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/22/2024).

A public exploit has been developed by Daniel García Gutiérrez/Manuel Blanco Parajón in C++ and been published 3 weeks after the advisory. The exploit is shared for download at github.com. It is declared as highly functional. As 0-day the estimated underground price was around $100k and more. A worm is spreading, which is automatically exploiting this vulnerability. The advisory illustrates:

To exploit the vulnerability against a server, an unauthenticated attacker could send a specially crafted packet to a targeted SMBv3 server. To exploit the vulnerability against a client, an unauthenticated attacker would need to configure a malicious SMBv3 server and convince a user to connect to it.
This issue was added on 02/10/2022 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 08/10/2022:
Apply updates per vendor instructions.

Applying a patch is able to eliminate this problem. It is possible to mitigate the problem by applying the configuration setting Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" DisableCompression -Type DWORD -Value 1 -Force.It is possible to mitigate the weakness by firewalling tcp/445. The best possible mitigation is suggested to be patching the affected component. A possible mitigation has been published immediately after the disclosure of the vulnerability.

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CPE 2.3info

CPE 2.2info

CVSSv4info

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CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.8

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 10.0
Vendor Vector (Microsoft): 🔍

NVD Base Score: 10.0
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Input validation
CWE: CWE-20
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Highly functional
Author: Daniel García Gutiérrez/Manuel Blanco Parajón
Wormified: 🔍
Programming Language: 🔍
Download: 🔍

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Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Patch
Status: 🔍

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Config: Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" DisableCompression -Type DWORD -Value 1 -Force
Firewalling: 🔍

Timelineinfo

11/04/2019 🔍
03/12/2020 +129 days 🔍
03/12/2020 +0 days 🔍
03/13/2020 +1 days 🔍
03/30/2020 +17 days 🔍
04/22/2024 +1484 days 🔍

Sourcesinfo

Vendor: microsoft.com
Product: microsoft.com

Advisory: 156731
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2020-0796 (🔍)
scip Labs: https://www.scip.ch/en/?labs.20161215

Entryinfo

Created: 03/13/2020 13:09
Updated: 04/22/2024 20:30
Changes: 03/13/2020 13:09 (58), 03/13/2020 15:27 (19), 04/05/2020 12:05 (4), 10/29/2020 09:42 (5), 04/13/2024 13:10 (18), 04/22/2024 20:30 (9)
Complete: 🔍
Committer: misc

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