Microsoft Office was once again diagnosed with a security problem. And this is the third problem on this week.

This problem was discovered by Symantec on Thursday. Symantec said that flash files embedded in Office documents could run and execute code without any warning.

“A successful attack may allow attackers to access sensitive information and potentially execute malicious commands on a vulnerable computer,” Symantec said in the alert, which was sent to users of its DeepSight security intelligence. The vulnerability was reported by researcher Debasis Mohanty.

The issue relates to the ability to load ActiveX controls in an Office document and is not a vulnerability but an Office feature, a Microsoft representative said. “This behavior is by design and by itself does not represent a security risk to customers,” he said. An ActiveX control is a small application typically used to make Web sites more interactive.

Anyway, they admitted that an attacker could abuse this feature and load an ActiveX control on a user’s system through an Office document. Still, Microsoft is not aware of any ActiveX controls that could allow an attacker to hijack a vulnerable PC in this way.

“Microsoft will continue to investigate the public reports to help provide additional guidance for customers as necessary,”, “If any vulnerable ActiveX controls are found, it is possible to prevent execution in recent versions of Office by setting a so-called “killbit” for these controls, according to Microsoft.” - Microsoft representative

This security hole is the third of this week. First, they discovered a flaw related to “hlink.dll”, a Windows file that could cause Excel to crash after a malicious file is opened. Also, the same problem allows an attacker to execute code. Next, the same Excel is having problems. It’s about a zero-day flaw. The malicious Excel document is sent as an e-mail attachment or otherwise delivered by the attacker to the intended victim. The file contains a Trojan horse called Mdropper.j and also a program “Booli.A” that can download more infected files to your computer.

All the problems were discovered by Symantec, the same company that Microsoft wants to take out of business by lowering the price on their services so much so they go bankrupt. Maybe they are also pissed that Symantec finds so many problems with their software?