The first three U.S. Variants of the Galaxy S III were all rooted the same way. Odin flash an insecure kernel, flash custom recovery, flash Superuser, and profit. With the Verizon Galaxy S III lagging behind the rest, many users had hoped that it would be rooted in the same manner when it was finally released—if not for the fact that the other three variants were rooted that way, then because Samsung hasn’t shipped a locked down device in recent memory. Apparently, Verizon has pulled a Motorola and locked the device down, making it impervious to the traditional root methods.
The problem was first documented by XDA Senior Member AdamLange in his thread that would have been a root tutorial. After several failed attempts at flashing the insecure kernel via Odin, AdamLange and others came to the conclusion that Verizon had slipped in a security check that prevented unsigned boot and recovery images from being flashed via Odin. Given that this is the method all the other Galaxy S III variants use to obtian root, this presents a big problem.
While there will likely be a workaround to this problem as there was for those stubborn HTC devices, that doesn’t mean that users aren’t angry. With work being done to find a workaround in AdamLange’s thread, XDA Recognized Developer incubus26jc has gone another route by starting a petition.