What is it?
Winupdate.exe is a file associated with a virus called w32.Gaobot.BIA

What does it do?
W32.gaobot.bia is a network-aware worm that spreads to remote network shares, through backdoors opened by other common backdoor Trojan horse programs, and by exploiting several Windows vulnerabilities. The worm opens a backdoor and allows a remote attacker to have unauthorized access to the infected computer.


More information and removal instructions
@symantec