They allege they do have sensitive information about the Justice Department, though. The group took over the United States Sentencing Service website early Saturday. The site has been taken down now, but The Verge pointed out you can still see the defaced-by-Anonymous version through this Google cache.
According to the lengthy note left on the site, the attack was carried out in the name of Aaron Swartz, the hacker and activist who committed suicide two weeks ago:
"Two weeks ago today, a line was crossed. Two weeks ago today, Aaron Swartz was killed. Killed because he faced an impossible choice. Killed because he was forced into playing a game he could not win -- a twisted and distorted perversion of justice -- a game where the only winning move was not to play."
Anonymous claims to have hacked multiple government websites and accumulated a wealth of sensitive information they plan to release in "warheads," a fancy, terrifying-at-first word they're using to call document dumps. The first one is/was called U S - D O J - L E A - 2013 . A E E 256, and it was supposed to be available to download on the Sentencing Service website, but clicking the alleged link only ever returned an error message.
So, yeah, no missiles. Only sensitive government information:
The contents are various and we won't ruin the speculation by revealing them. Suffice it to say, everyone has secrets, and some things are not meant to be public. At a regular interval commencing today, we will choose one media outlet and supply them with heavily redacted partial contents of the file. Any media outlets wishing to be eligible for this program must include within their reporting a means of secure communications.
Each "warhead" is named for a Supreme Court judge. The attack seems to have been months in the making, if the note left by the hackers is to be believed. They said they only "wound down" the attack in the two weeks since Swartz's death.
There are demands. The hackers who carried out the attack want "reform of outdated and poorly-envisioned legislation," "reform of mandatory minimum sentencing," and "a return to proportionality of punishment with respect to actual harm caused," if the Justice Department wants their information to stay private.
This isn't the first time Anonymous has become involved with the fallout from Swartz's death. They were able to keep the Westboro Baptist Church from protesting Swartz's funeral with an extremely successful social media campaign. But we suspect the prosecutor defending the decision to seek jail time in Swartz's complicated case drew the attention of the hacking group.
What happens next is anyone's guess. There are immediate questions like, do they actually have any sensitive information? Are they bluffing? The FBI told CNN they're already looking into it. A criminal case has been opened. Whether or not they find anything, or traces of anyone, will be interesting to see.