Company says buy will improve consulting contacts and provide products to help recover lost passwords and improve site security.
@stake will improve Symantec's consulting contacts--six of the top 10 financial institutions are customers, Symantec said. Symantec also will get products to help check and recover lost passwords and to test and improve Web site security.
The deal is expected to close in October, but terms were not disclosed.
@stake was founded by members of "l0pht," one of the original "gray hat" hacker groups. Originally, such groups wanted to distance themselves from both corporations and malicious "black hat" hackers.
The acquisition won't be the first time Symantec has tapped the old-school hacker community for expertise. In 2002, Symantec bought SecurityFocus, which runs the active BugTraq mailing list about software vulnerabilities.
The move counters a step by one of Symantec's main rivals, McAfee, which in August acquired security specialist Foundstone. Symantec has acquired several security companies in recent years.