Vulnerability identifier: #VU2944

Vulnerability risk: High

CVSSv3.1: 9.2 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2011-0104

CWE-ID: CWE-119

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Microsoft Excel
Client/Desktop applications / Office applications
Microsoft Office for Mac
Client/Desktop applications / Office applications

Vendor: Microsoft

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

The weakness exists due to buffer overflow during validation of record information. A remote attacker can create a specially crafted Excel file, trick the victim into opening it, trigger memory corruption and execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability results in arbitrary code execution on the vulnerable system.

Mitigation
Install update from vendor's website:

Microsoft Excel 2002 Service Pack 3:
https://www.microsoft.com/downloads/details.aspx?familyid=db2c5cfe-588c-4646-b86a-3fb8248f7af4
http://go.microsoft.com/fwlink/?LinkId=200529
Microsoft Excel 2003 Service Pack 3:
https://www.microsoft.com/downloads/details.aspx?familyid=916a076d-d754-4092-b23d-c8826db7e397
http://go.microsoft.com/fwlink/?LinkId=200529
Microsoft Office 2004 for Mac:
https://www.microsoft.com/downloads/details.aspx?FamilyID=f756d836-6ab2-4adb-9dee-6cb523d7c1f5
Microsoft Office 2008 for Mac:
https://www.microsoft.com/downloads/details.aspx?FamilyID=84dfe3f4-a2a1-47b9-8da1-29ae67230918
http://go.microsoft.com/fwlink/?LinkId=203241
Open XML File Format Converter for Mac:
https://www.microsoft.com/downloads/details.aspx?FamilyID=0c323a12-6385-4666-ad39-a9516a8eda14
http://go.microsoft.com/fwlink/?LinkId=203241

Vulnerable software versions

Microsoft Excel:

Microsoft Office for Mac: 2004 - 2008

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External links
http://technet.microsoft.com/en-us/library/security/ms11-021.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?

Yes. This vulnerability is being exploited in the wild.