The Redmond giant has its YouTube account hacked, just a week after hardcore pornography was posted on the Sesame Street channel.
The hack came just a week after the Sesame Street YouTube channel was hit, when somewhat more lurid material was posted online.
In Microsoft’s case, the hackers called on web users to post video responses, create new background images or provide sponsorship, according to Sophos senior technology consultant Graham Cluley.
Regardless of how the hack occurred, it's embarrassing and inconvenient for Microsoft.
Another appeared to take footage from the LA Noire videogame, with one character shooting another in the head.
“It seems unlikely that the change to the YouTube channel is a bizarre publicity stunt by Microsoft,” Cluley said in a blog post.
“After all, what would be the sense in deleting its archive of past videos - many of which are embedded on third-party sites around the world?”
Cluley, who took a screen grab of the hacked YouTube channel (see below), suggested a Microsoft employee may have been careless with a password, leaving the account open for hacking.
“Regardless of how the hack occurred, it's embarrassing and inconvenient for Microsoft,” he added.
The channel has been recovered by Microsoft, however, with standard advertising and videos running.
"We have regained control of the Microsoft channel on YouTube, and we are working to restore all of the original content," a Microsoft spokesperson said. "We will continue to work with YouTube to ensure safeguards are in place for the future."
When Sesame Street’s YouTube account was compromised last week, pornographic videos were posted and the profile changed.