Zero-day vulnerability in Microsoft Excel

Memory corruption
CVE-2009-1134

The vulnerability has been exploited over a year and was reported to vendor on 2009-03-26.
According to Symantec the first exploitation of the vulnerability was discovered on 2008-07-25.

Known malware:

Bloodhound.Exploit.254.

Vulnerability details

Advisory: SB2009060902 - Multiple vulnerabilities in Microsoft Excel

Vulnerable component: Microsoft Excel

CVE-ID: CVE-2009-1134

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C

CWE-ID: CWE-119 - Memory corruption

Description:

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

The weakness exists due to buffer overflow when parsing the Excel spreadsheet file format. A remote attacker can create a specially crafted Excel file containing a malformed record pointer, 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 the vulnerability results in arbitrary code execution on the vulnerable system.

Note: according to reports this vulnerability was being actively exploited before Microsoft issued security patch.

External links:

https://downloads.avaya.com/css/P8/documents/100062475
http://www.securityfocus.com/archive/1/archive/1/504213/100/0/threaded
https://technet.microsoft.com/en-us/library/security/ms09-021.aspx
https://books.google.com.ua/books?id=1E0SCAAAQBAJ&pg=PA275&lpg=PA275&dq=CVE-2009-1134&source=bl&ots=...
https://fe-ddis.dk/cfcs/CFCSDocuments/Zeroday.pdf
https://users.ece.cmu.edu/~tdumitra/public_documents/bilge12_zero_day.pdf

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.