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AUSCERT Security Bulletin
ASB-2022.0127.2
Microsoft Windows Support Diagnostic Tool (MSDT) Remote Code
Execution Vulnerability
15 June 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Microsoft Office
Operating System: Windows
Resolution: Patch/Upgrade
CVE Names: CVE-2022-30190
Comment: CVSS (Max): 7.8 CVE-2022-30190 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
CVSS Source: Microsoft
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Revision History: June 15 2022: Microsoft has released fixes to address this vulnerability
May 31 2022: Initial Release
OVERVIEW
A new zero-day vulnerability has been identified allowing remote code execution
in Microsoft Office via the ms-msdt protocol scheme. [1]
The vulnerability is dubbed as "Follina".
The SANS Internet Storm Center has produced a blog with more details including a sample management briefing. [3]
Microsoft has issued CVE-2022-30190 regarding this vulnerability.
Microsoft has also reported that an exploit has been publicly disclosed. [2]
IMPACT
Microsoft has given the following details regarding the vulnerability.
Details Impact Severity
CVE-2022-30190 Remote Code Execution Important
MITIGATION
Microsoft recommends the following workarounds: [4]
To disable the MSDT URL Protocol
'Disabling MSDT URL protocol prevents troubleshooters being launched as links
including links throughout the operating system. Troubleshooters can still be
accessed using the Get Help application and in system settings as other or
additional troubleshooters. Follow these steps to disable:
Run Command Prompt as Administrator.
To back up the registry key, execute the command "reg export HKEY_CLASSES_ROOT\ms-msdt filename"
Execute the command "reg delete HKEY_CLASSES_ROOT\ms-msdt /f"
How to undo the workaround
Run Command Prompt as Administrator.
To back up the registry key, execute the command "reg import filename"'
Update: Fixes are now available for this vulnerability. [2]
REFERENCES
[1] Zero-day vuln in Microsoft Office: 'Follina' will work even when
macros are disabled
https://www.theregister.com/2022/05/30/follina_microsoft_office_vulnerability/
[2] Microsoft Windows Support Diagnostic Tool (MSDT) Remote Code
Execution Vulnerability
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2022-30190
[3] New Microsoft Office Attack Vector via "ms-msdt" Protocol Scheme
https://isc.sans.edu/forums/diary/New+Microsoft+Office+Attack+Vector+via+msmsdt+Protocol+Scheme/28694/
[4] Guidance for CVE-2022-30190 Microsoft Support Diagnostic Tool
Vulnerability
https://msrc-blog.microsoft.com/2022/05/30/guidance-for-cve-2022-30190-microsoft-support-diagnostic-tool-vulnerability/
AusCERT has made every effort to ensure that the information contained
in this document is accurate. However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. AusCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.
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Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
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