Vulnerability identifier: #VU7192

Vulnerability risk: High

CVSSv3.1: 8.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-8558

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Microsoft Security Essentials
Client/Desktop applications / Antivirus software/Personal firewalls
Microsoft Endpoint Protection
Client/Desktop applications / Antivirus software/Personal firewalls
Windows Defender
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: Microsoft

Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The weakness exists due to boundary error when scanning malicious files by  the Microsoft Malware Protection Engine. A remote attacker can send a specially crafted file, trick the victim into opening it and execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Microsoft Security Essentials: All versions

Microsoft Endpoint Protection: 2010

Microsoft Endpoint Protection: All versions

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

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-8558

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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. However, proof of concept for this vulnerability is available.