Here’s how the folks behind the release explain why they targeted Mantech:
What ManTech has to do with the FBI? Well, quite simple: In Summer 2010 the FBI had the glorious idea to outsource their Cybersecurity to ManTech. Value of the contract: 100 Million US-Dollar… Well done, good sirs. You failed epically. Because we pwned ManTech utterly and throughly; and we did not need hundreds of millions for it. In fact, we did not require any funds at all, we did it with Lulz.