Hackers have released another attack code that exploits a critical vulnerability in Microsoft\u2019s Word software\u2014the third such bug to be disclosed in the past week.The proof-of-concept code was posted Tuesday on the Milw0rm.com website, making it widely available to the hacking community. It exploits a previously unreported bug in Word.Like the other recent Word bugs disclosed this past week, it could possibly be used by attackers to run unauthorized software on a victim\u2019s computer, said David Marcus, security research and communications manager with McAfee\u2019s Avert Labs.Attackers have been using these Word exploits in extremely targeted attacks, where a small number of victims are sent an e-mail with a maliciously encoded Word document attached. The hackers use social engineering techniques to try to trick the victim into opening the dangerous attachment.For example, in a recent Word attack, first reported Sunday, the malicious e-mail "was sent to a very high-profile company, directly to three people at the company," Marcus said.Microsoft is investigating reports of this latest Word bug, a spokesman for the company\u2019s public relations agency said.Though they are not being widely exploited, the unpatched Word vulnerabilities are causing some enterprises concern.At the Port of Seattle, for example, users are being cautioned and e-mail with Word attachments is getting a little more scrutiny, said Ernie Hayden, chief information security manager with the port. "We\u2019ve done some blocking on our e-mail, and we\u2019ve had dialogue with people with respect to what our expectations are," he said.Attacks on Microsoft\u2019s Office software have been on the rise for months now, said Marc Maiffret, chief technology officer with security vendor eEye Digital Security. Office vulnerabilities were once released "on a monthly basis," he said. "Now we\u2019re at the point where it\u2019s almost daily."Still, publishing attack code ultimately works contrary to the interests of the bad guys, he added. "It\u2019s kind of disruptive, and it creates a panic," he said. "But all it does is make the industry focus and come up with a resolution."By Robert McMillan, IDG News Service (San Francisco Bureau)Related Links: \n\n\n\nNo Patch Yet for New Word Zero-Day Flaw\n\nNew Attack Targets Microsoft WordCheck out our CIO News Alerts and Tech Informer pages for more updated news coverage.