The attacks began during the long holiday weekend and were first noticed by SCO on Sunday evening, a company spokesman says.
In the first defacement, hackers inserted "SCO vs World" at the top of one of the site's pages. The phony text went on to state that SCO had discovered "parts of our code in almost all Microsoft(R) software. We want to bring an action against Microsoft(R) and our legal department is working on that."
The second defacement included a hacked banner on the company's home page that read, "We Own All of Your Code, pay us all your money."
The SCO spokesman says the company has fixed the security flaw that made the defacement possible. No further details were provided.
Attacks against SCO's site are not new. The company was attacked earlier this year by hackers who were apparently upset about legal challenges launched by SCO against the open-source Linux operating system.
In January, a variant of the MyDoom virus struck the Internet and was wired to launch a denial-of-service attack against both Microsoft's and SCO's Web sites. While Microsoft weathered that attack, SCO was forced to create a temporary home page after its primary Web page was knocked offline.