Chinese officials no longer approve the use of the two antivirus software vendors, according to reports.
Board member Michael Brown will serve as interim CEO while maker of Norton antivirus software hunts for its second chief executive in two years.
Security firms and Google reported DOS attacks on Web sites of Vietnamese activists.
Symantec's widely used and much maligned line of Norton security suites will get a major overhaul in September.
Hackable location tracking, poor password management, and a lack of privacy policies: Symantec has a number of concerns about the fitness tracking boom.
The security firm is confronting the ZeroAccess botnet, which is likely to have more than 1.9 million slave computers at its disposal for click fraud and bitcoin mining.
Chinese antitrust regulators also raided the offices of IT firm Accenture, one of the software giant's consulting partners.
Police and security firms team up to take down the notorious Shylock, a dangerous financial Trojan that has infected at least 30,000 Windows computers worldwide.
Group that includes Symantec, VeriSign, and Microsoft tags Twitter tops among 800 websites for user protection, security.
The security solutions provider is cutting about 1,000 positions this month, and another 700 in July, according to a report. The company calls those numbers "pure speculation" but doesn't share its own figures.