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CERT Coordination Center

Microsoft Windows Type 1 font parsing remote code execution vulnerabilities

Vulnerability Note VU#354840

Original Release Date: 2020-03-23 | Last Revised: 2020-03-24

Overview

Microsoft Windows contains two vulnerabilities in the parsing of Adobe Type 1 fonts, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable system.

Description

Adobe Type Manager, which is provided by atmfd.dll, is a kernel module that is provided by Windows and provides support for OpenType fonts. Two vulnerabilities in the Microsoft Windows Adobe Type Manager library may allow an unauthenticated remote attacker to execute arbitrary code on a vulnerable system. This vulnerability affects all supported versions of Windows, as well as Windows 7. This vulnerability is being exploited in the wild.

Impact

By causing a Windows system to open a specially crafted document or view it in the Windows preview pane, an unauthenticated remote attacker may be able to execute arbitrary code with kernel privileges on a vulnerable system. Windows 10 based operating systems would execute the code with limited privileges, in an AppContainer sandbox.

Solution

The CERT/CC is currently unaware of a practical solution to this problem. Please consider the following workarounds that are listed in Microsoft Security Advisory ADV200006:

Rename ATMFD.DLL

This mitigation appears to be to the most effective workaround for this vulnerability, as it blocks the vulnerable code from being used by Windows. Please see Microsoft Security Advisory ADV200006 for more details. Because supported Windows 10 versions do not use ATMFD.DLL, this mitigation is not applicable.

Disable the preview pane and details pane in Windows Explorer

Please see Microsoft Security Advisory ADV200006 for more details.

Disable the WebClient service

Please see Microsoft Security Advisory ADV200006 for more details.

Vendor Information

354840
 
Affected   Unknown   Unaffected

Microsoft

Notified:  March 23, 2020 Updated:  March 23, 2020

Status

  Affected

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

Vendor References


CVSS Metrics

Group Score Vector
Base 10 AV:N/AC:L/Au:N/C:C/I:C/A:C
Temporal 9 E:F/RL:W/RC:C
Environmental 9.0 CDP:ND/TD:H/CR:ND/IR:ND/AR:ND

References

Acknowledgements

This document was written by Will Dormann.

Other Information

CVE IDs: None
Date Public: 2020-03-23
Date First Published: 2020-03-23
Date Last Updated: 2020-03-24 17:36 UTC
Document Revision: 20

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