Vulnerability identifier: #VU6800

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-8539

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Malware Protection Engine
Client/Desktop applications / Antivirus software/Personal firewalls
Windows Defender
Client/Desktop applications / Antivirus software/Personal firewalls
Microsoft Security Essentials
Client/Desktop applications / Antivirus software/Personal firewalls
Microsoft Endpoint Protection
Client/Desktop applications / Antivirus software/Personal firewalls
Windows Intune Endpoint Protection
Client/Desktop applications / Antivirus software/Personal firewalls
Microsoft Forefront Endpoint Protection
Server applications / DLP, anti-spam, sniffers
Microsoft Exchange Server
Server applications / Mail servers

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an error when processing specially crafted files within Microsoft Malware Protection Engine (mpengine.dll). A remote attacker can create a specially crafted file, pass it to the affected application and trigger a scan timeout.

Successful exploitation of the vulnerability may allow an attacker to disable anti-malware protection on the system until the affected service is restarted.

Mitigation
Update Microsoft Malware Protection Engine (mpengine.dll) to version 1.1.13804.0.

Vulnerable software versions

Microsoft Malware Protection Engine: 1.1.13704.0

Windows Defender: for Windows 8.1 - on Windows 7 for 32-bit Systems Service Pack 1

Microsoft Security Essentials: All versions

Microsoft Forefront Endpoint Protection: 2010

Microsoft Endpoint Protection: All versions

Microsoft Exchange Server: 2013 RTM 15.00.0516.032, 2016 RTM 15.01.0225.042

Windows Intune Endpoint Protection: All versions

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-8539

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.