GCHQ in 1987. (Sludgeulper)

An international nonprofit is suing the British counterpart to the NSA in what the group says is the country's first-ever legal challenge to device-hacking by intelligence services.

The watchdog, Privacy International, says that while former NSA contractor Edward Snowden drew a great deal of attention to the Government Communications Headquarters' (GCHQ) attempts to eavesdrop on people's communications, the spy agency's efforts to break into electronic devices is far more pernicious.

In a 21-page complaint filed to a British special court and obtained by The Washington Post, Privacy International has accused GCHQ of installing malware on unsuspecting targets' mobile phones, computers and Web cams that can capture keystrokes, secretly activate microphones and obtain sensitive information such as usernames and passwords and even the content of communications, such as text messages and e-mails stored on a device.

"If the interception of communications is the modern equivalent of wiretapping," according to the complaint, "then the activity at issue in this complaint is the modern equivalent of entering someone’s house, searching through his filing cabinets, diaries and correspondence, and planting devices to permit constant surveillance in future, and, if mobile devices are involved, obtaining historical information including every location he visited in the past year."

The filing invokes the European Convention on Human Rights. If a private citizen were to try doing what GCHQ does routinely, Privacy International alleges, it would run afoul of British cybercrime law.

GCHQ declined to comment.

The complaint goes to a tribunal with the sole power to investigate alleged abuses at MI5, MI6 and GCHQ. The judicial body has historically sided with the government, with only a small fraction of cases being upheld since 2001. According to Privacy International's director Eric King, the Investigatory Powers Tribunal tells complainants only the results of its deliberations. Those who allege improper surveillance but whose cases get thrown out aren't told why.

"All of this is being done without any public debate at all in the U.K.," King said in an interview, "and more importantly, there's no clear legal framework to justify such intrusion."