From the folks at Wired comes this
While investigating a hosting company known for sheltering child porn last year the FBI incidentally seized the entire e-mail database of a popular anonymous webmail service called TorMail.
Now the FBI is tapping that vast trove of e-mail in unrelated investigations.
The tactic suggests the FBI is adapting to the age of big-data with an NSA-style collect-everything approach, gathering information into a virtual lock box, and leaving it there until it can obtain specific authority to tap it later. There’s no indication that the FBI searched the trove for incriminating evidence before getting a warrant. But now that it has a copy of TorMail’s servers, the bureau can execute endless search warrants on a mail service that once boasted of being immune to spying.
And even without a specific warrant, many of the service's users have also been 'de-anonymized' after a bit of malware was introduced to the service site's webpage:
According to the new document, the FBI obtained the data belonging to Freedom Hosting’s customers through a Mutual Legal Assistance request to France – where the company leased its servers – between July 22, 2013 and August 2 of last year.
That’s two days before all the sites hosted by Freedom Hosting , including TorMail, began serving an error message with hidden code embedded in the page, on August 4.
Security researchers dissected the code and found it exploited a security hole in Firefox to de-anonymize users with slightly outdated versions of Tor Browser Bundle, reporting back to a mysterious server in Northern Virginia. Though the FBI hasn’t commented (and declined to speak for this story), the malware’s behavior was consistent with the FBI’s spyware deployments, now known as a “Network Investigative Technique.”
No mass deployment of the FBI’s malware had ever before been spotted in the wild.
Gee, what a surprise, huh?