A group working under the Anonymous banner has release Anonymosus-OS, a derivative of the Ubuntu GNU/Linux distribution optimized for doing Anonymous-style stuff, with a bunch of "security testing" tools included in the distro. Given recent revelations about the infected version of the Low-Orbit Ion Cannon, it would be prudent to manually verify all the package checksums before using this.Having worked in Internet security for over 20 years, this does not surprise me.
The mere fact that someone claims to be releasing the program is not proof that the 'real' Anonymous did this (whatever that might mean). It is quite possible, likely even, that this particular bundle of malware is the work of another group that just thought it would be a clever idea to hijack the Anonymous brand to promote it.
Update: Some people seem to be upset that I attributed the attack to 'Anonymous'. But that is precisely what the rules of the group allow any cracker to do. Either anyone who wants to use the anonymous brand can use it for any purpose they choose or there are rules. If people preach anarchy they have to stand accountable for all the acts they incite and not just the ones that prove popular.
Update2: Subsequent reports of the behavior of the system suggest that the system may not be so much 'infected' as loaded up with hacking tools that have some 'interesting' default settings. The default setting for Low Orbit Ion Canon for example is to launch a Denial of Service attack on the host machine. So now the 'real' Anonymous (whatever that might mean) is denying authorship as the product is lame rather than because it is malicious.