http://www.wsj.com/articles/frances-tv5monde-hacked-by-group-claiming-to-be-islamic-state-1428581883?mod=e2fb

ARIS—French broadcaster TV5Monde was working to get its systems back on track Thursday after an “extremely powerful” cyberattack by hackers claiming allegiance to Islamic State knocked the company’s channels off the air globally—a new indication of the militant group’s technological capabilities.

The broadcaster, which airs French-language content on 11 channels world-wide and is indirectly owned by the governments of France and other French-speaking countries, said hackers penetrated the computer systems at its Paris headquarters late Wednesday evening, shutting down everything from company email and production facilities to the computer servers TV5Monde uses to send its television signals.

At the same time, the hackers took control of the broadcaster’s social media accounts on platforms including Facebook Inc. and Twitter Inc., posting terrorist propaganda in support of Islamic State, including some alleged personal details about French military personnel, a spokeswoman for the channel said.

“Those terrorists, as they are certainly terrorists—we are checking on the claim—are using the most advanced technologies,” said Laurent Fabius, France’s foreign minister, after a visit to the TV5 offices on Thursday morning. “Everything is being done to find the authors, punish them, re-establish broadcasting and then prevent such cyberterrorism attacks from threatening freedom of speech in the future.”

By Thursday morning, the company had regained control of its social media accounts, but had only restored one feed to its global channels and its website was still offline. Email and other internal systems that produce daily news programs remained inaccessible, the broadcaster said.

The hacking, which is now being investigated by French intelligence, offers potential evidence of the militant group’s growing capacity to conduct technological warfare. While hackers claiming allegiance to the group have been active in recent months in posting propaganda to websites and high-profile social media accounts—including one belonging to the U.S.—this appears to be the first successful takedown of a high-profile TV channel, experts said.

A former intelligence official, briefed on the cybersecurity systems at TV5Monde, said the channel’s essential broadcasting systems weren’t sequestered from its office functions, making an effort to hack those systems more achievable. The hack may have worked by obtaining the access credentials of staffers who work at the channel, the person said.

Since the summer, Islamic State has stepped up its propaganda targeting Western audiences by establishing Twitter accounts in French, Russian and Albanian, among other languages. The group also launched its first English-language magazine named Dabiq in July 2014, coinciding with its blitz across western Iraq in June. At the time, the insurgents consolidated territory seized there with gains in northeastern Syria to declare a caliphate, or Islamic Empire.

France has been a particular target. In the days following the Charlie Hebdo attacks, French officials said hacker groups linked with Islamist organizations in Syria and elsewhere defaced as many as 19,000 websites—frequently those of local municipalities and universities—by posting Islamic State propaganda. But officials said those attacks targeted mostly older websites without up-to-date security features.

Hackers also attempted—unsuccessfully—to gain control of the publication system of the French newspaper Le Monde, the paper said. That attack worked by convincing staff members to turn over internal email passwords and attempting to use those credentials to access internal systems, the paper said.

The propaganda has helped Islamic State draw in more European and American recruits, Western officials say, attracted to the group’s sleekly packaged videos interviewing international fighters about what is described as the glamorous lifestyle of waging jihad in Syria.

Islamic State has some 20,000 foreign fighters in its ranks, according to the International Center for the Study of Radicalization. Most of them come from the Middle East, but nearly 4,000 carry European passports, the center says.