It is not safe to update on untrusted networks.

There have been a rise in malicious updates in the past few months. It has  gotten so out of hand that the FBI has published warnings to not update your computers or any unsigned software updates on any untrusted network. Basically the little pop-ups that you get that claims there is a newer version of the software you are using, even the Windows updates, are not safe to do until you get home or to a network that you can trust.

This has been made possible by recently popular tool called evilgrade created by infobytesec. They have released this with over 60 modules that can that can be used to update different software. Some the software vulnerable to this attack are: Teamviewer, CCleaner, Java, Apple update, WinAmp, Virtualbox, VMWare, Skype and many more in their README.

There are a few ways to mitigate your risk. First turn off automatic updates, this will prevent any malicious updates from installing without prompting you first. Second, if you have to update on an untrusted network you can check to see if the update is signed, not all companies do this which make the attack very effective. If the update is not signed or you cannot find the signature you can go to the manufactures website and see what the latest version is. If you version is behind the latest you can update or download the lasted software from the vendor and install it to become up-to-date. Lastly, only install updates on a trusted network like your home.