Istbar is adware for Internet Explorer which can install a new IE toolbar, change your default homepage, and/or start porn pop-ups.  Istbar is rather easy to notice since it begins a toolbar for Internet Explorer and displays pop-up advertisements for pornography sites.  Istbar will also change Internet Explorer's homepage to www.slotch.com. 

Istabar is not a mobile device virus, but is usually dropped by the CardTrap virus so when the device is connected to a PC running Windows, Istbar will be transferred to the PC and installed.