Downloading AutoCAD from unofficial sources through "portable links" carries significant risks:
A "portable" app is typically a repackaged version of software designed to run without being formally installed on a host operating system. It usually lives in a single folder or on a USB drive. autocad portable 2012 64 link
Should You Use the Portable Or Installed Version of Software? autocad portable 2012 64 link
Many users prefer the 2012 interface and its introduction of features like associative arrays and multifunctional grips. Risks of Using "Portable" Links autocad portable 2012 64 link
They can often run without administrative privileges, which is useful in restricted IT environments.