Isn't anything safe from hackers? Now they've apparently found a way to hack into systems through a media stream, threatening users with denial of service attacks that can bring down servers and desktops alike. The vulnerability was reported yesterday by VoIPshield Laboratories, a security tools maker in Canada.

The flaws were found in Microsoft Office Communications Server 2007, Office Communicator and Windows Live Messenger, which Microsoft said could impact as many as 250 million people. The flaws also affect many other applications and systems that use the Real-time Transport Protocol (RTP), including those from Avaya, Cisco and Nortel, according to the report.

"Securing the media stream is particularly challenging because once the messaging session is established, the flow of packets is not always monitored and managed by the call server," according to a statement from VoIPshield Labs, the research division of VoIPshield Systems. Microsoft is investigating the flaws, it said, but so far has not issued any security advisories or updates.

But denial of service are not the only threats to worry about. Andriy Markov, director of VoIPshield Labs, told TMCnet.com that "many other media stream attacks exist that have more severe implications than service availability. We’re presently validating new research that shows an attacker can gain unauthorized access to an unsuspecting user’s laptop by manipulating the packets of a VoIP phone call. We believe that these attacks can even be made to traverse a PSTN gateway.”

Is this the real world or a Wachowski brothers movie?