A software blacklist is a list of software that is deemed inappropriate by a specific program. Programs from different companies have different blacklists, and many don’t have one at all. If a blacklisted program is present on the system, the bothered program may malfunction or report information to a central server. Like most digital rights management (DRM) measures, the software blacklist has come under fire from a number of different groups.
Software blacklisting is a relatively simple process. Programs will scan the computer’s registry of installed programs looking for a number of different pieces of software. If any of the programs on the software blacklist are found, the program executes a specific set of instructions. It is common for a scan to occur on installation, but nothing stops a program from periodically scanning later.
There are a number of common programs that are found on a basic software blacklist. Programs that are used by hackers, such as disk duplicators, software debuggers or patch creators, are common. Also among these lists are several disk-authoring programs that have the ability to mount disk images on virtual drives. It is this last group that causes the most unintentional positives on a software blacklist, as this type of burning software is very common.
When a blacklisted program is found, the program could do any number of things. In many cases, the program will not install at all without giving the user a reason why. Some programs install properly, but have reduced features, operate in a trial mode, or crash when executing certain functions. With the increase in constant Internet connections, many programs will communicate their findings to a central server, which will give them specific restriction instructions based on the program located.
As with many DRM methods, the software blacklist has seen a lot of controversy. In the early days of this technology, false positives were a major problem. Users that were completely legitimate would end up locked out of software often with no explanation as to why. Other users would find that programs that came pre-installed on their computers would leave behind registry markers even after they were uninstalled. These registry markers would prevent the installation of other programs due to an over-restrictive blacklist.
On the other hand, a software blacklist does little to stop hackers. There are several methods of circumventing a blacklist; installing software on a different operating system boot, patching blacklisted programs to alter their version numbers, or simply running a separate program that prevents the blacklist from scanning the computer. As a result, it is common for software blacklisting to hurt legitimate users rather than stop illegitimate ones.