Watch out for malicious Word documents.
Another previously undocumented, yet-to-be-patched security
vulnerability in Microsoft Word is actively being exploited in
cyberattacks, Microsoft said Thursday.
The vulnerability is the fourth zero-day vulnerability to arise in
the Microsoft application in two months. Microsoft hasn't provided
patches for any of the flaws, despite acknowledging that the holes
are being used in attacks on its customers.
"There have been very limited attacks reported that are attempting
to use the reported vulnerability at this time," a Microsoft
representative said Thursday in a statement about the latest
problem. The company is investigating this latest report and may
issue a patch, if needed, the representative said.
The newest problem allows an attacker to hijack systems running
Word 2000 and causes a crash of Word 2003 and Word XP, Symantec
said in an alert Thursday. "An attacker could exploit this issue by
enticing a victim to open a malicious Word file," the Cupertino,
Calif.-based security company said.
Security experts have said the limited-scale attacks are the most
dangerous. Widespread worms, viruses or Trojan horses sent to
millions of mailboxes are typically not a grave concern because
they can be blocked. Instead, especially for businesses, targeted
Trojan horses have become nightmares, as they can fly under the
radar.
Symantec advises people to make sure their security software is
up-to-date and urges caution when opening Word documents.
Businesses should put policies in place to prevent Word documents
from being distributed to users, Symantec said.
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Nowadays attackers so clever... always release exploit one by one.
So Microsoft can't patch. 
Anyway, not opening Word documents isn't a solution. Most of the
files are in Word. Even if you don't open Word documents, they will
force you to open other types of documents, which totally defeats
it.
Time to go open-source! 