Vulnerability identifier: #VU8274

Vulnerability risk: High

CVSSv3.1: 8.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-8631

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Excel
Client/Desktop applications / Office applications
Microsoft Excel for Mac
Client/Desktop applications / Office applications
Microsoft Office Compatibility Pack
Client/Desktop applications / Office applications
Microsoft Office Web Apps
Client/Desktop applications / Office applications
Excel Services on Microsoft SharePoint Server
Client/Desktop applications / Office applications
Office Online Server
Server applications / Other server solutions
Microsoft Excel Web App
Web applications / Other software

Vendor: Microsoft

Description

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

The vulnerability exists due to boundary error when processing Excel files. A remote unauthenticated attacker can create a specially crafted Excel file, trick the victim into opening it, trigger memory corruption and execute arbitrary code on the target system with privileges of the current user.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Excel:

Microsoft Excel for Mac: 2011 - 2016

Microsoft Office Compatibility Pack:

Microsoft Office Web Apps: 2013 Service Pack 1

Excel Services on Microsoft SharePoint Server: 2007 - 2010

Office Online Server : 2016

Microsoft Excel Web App: 2013 Service Pack 1

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2017-8631

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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.