Vulnerability identifier: #VU4343

Vulnerability risk: High

CVSSv3.1: 4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:F/RL:O/RC:C]

CVE-ID: CVE-2013-5054

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Office
Client/Desktop applications / Office applications

Vendor: Microsoft

Description
The vulnerability allows a remote attacker to obtain potentially sensitive information on the target system.

The weakness exists due to an error in handling of a specially crafted response when opening a malicious Office file. A remote attacker can create a specially crafted file using, host it on remote website, trick the victim into opening it and gain access to tokens used to authenticate the current user on a targeted SharePoint or other Microsoft Office server site.

Successful exploitation of the vulnerability results in information disclosure on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation
Install update from vendor's website:

Microsoft Office 2013 (32-bit editions):
https://www.microsoft.com/downloads/details.aspx?FamilyId=4daa3de8-4c70-498c-82d6-fe8250278e5e
Microsoft Office 2013 (64-bit editions):
https://www.microsoft.com/downloads/details.aspx?FamilyId=09f52670-bb42-425a-ac7b-1afddf82faea

Vulnerable software versions

Microsoft Office: 2013

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External links
http://technet.microsoft.com/en-us/library/security/ms13-104.aspx

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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, a fully functional exploit for this vulnerability is available.