According to Symantec, a great many of Anonymous hacktivists who participated in DDoS attacks using Low Orbit Ion Cannon (LOIC) lost their personal data to ZeuS Trojan.
The incident took place due to modification of the contents of a popular Pastebin guide on how to participate in Anonymous DDoS attacks. The LOIC download URL in this guide pointed at the tool that allowed conducting DoS attacks, but it also contained a ZeuS botnet client.
Link to Pastebin guide with the trojanised LOIC tool was posted on Tweeter by @youranonnews, a widely known outlet for Anonymous account with over half a million followers.
The @youranonnews is called this statement "wrong & libellous" and said it "NEVER posted the DDOS hijacker nor did we attempt to trick people; instead we WARNED of it". Archives show the URL was apparently tweeted by @youranonnews and not in the form of a warning – Symantec experts say.
Naked Security warns that that software installation from untrusted sources might harm your computer and compromise essential to you data. Please take care of your own security.
The full Symantec advisory is accessible here: