There's been someone going about phishing for Steam accounts in the last while going under the name "Admin", with the Steam Logo for an avatar. Don't fall for this. The message that they send will most likely look like this:

"Admin: Hello you are welcomed by the administration steam. It is necessary for you to connect or update protection SteamGuard to your account to make it be authorised in steam http://storensteampowered.com/upgradeguard . If you do not execute it, the account will be disconnected in a current of 5 hours! For disconnected and ban accounts steam responsibility does not bear!"

Block these people (or are they bots? Fuck if I know, or care), and report them tenfold for phishing/scamming/hacking!