Syria, and its Hacker Activists, Are Back on the Internet

Syrian Internet and cellphone access resumed Wednesday morning after an Internet failure pulled the company offline Tuesday.

The likely culprit, technologists say, was the Syrian government. But the Syrian government said the failure was because of a technical problem.

Bakr Bakr, the director general of Syria’s General Establishment for Communications, told the state-run Syrian Arab News Agency, or SANA, that the Internet failure was caused by a “malfunction in an optic cable,” but security experts said that such an occurrence would be unlikely.

There are four physical cables that connect Syria to the Internet, three run undersea and one runs over land through Turkey. The only way an outsider could pull off such an outage, security experts say, would be too physically cut all four cables simultaneously.

Evidence suggested that the state-run Syrian Telecommunications Establishment, the exclusive provider of Internet access in Syria, simultaneously withdrew the Border Gateway Protocol, or B.G.P., routes into Syria at roughly 7:45 p.m. E.D.T. on Tuesday, ensuring that any information trying to reach Syria could not find its way, according to Renesys, OpenDNS and Arbor Networks.

The same technique was used to shut down the Internet and mobile phone service last November. Syrian government officials said terrorists, not the government, were responsible for that failure, but evidence also pointed to government involvement.

“The way the routes were withdrawn was systematic and looked as if individual providers were cut off one after another,” said Matthew Prince, the founder of Cloudflare, a San Francisco start-up that distributes large volumes of traffic across the Internet.

Cloudflare discovered Wednesday morning that one small pocket of the Syrian Internet maintained access to the Internet through the failure, though it was not immediately clear who was using it. That, Mr. Prince said, further contradicted claims that a technical malfunction was to blame.

“That again is a strong indication that this was an explicit effort to turn off most (although not all) of the country’s Internet connectivity,” Mr. Prince said in an e-mail. “Had it been a true cable cut across all four of the country’s connections than this selective space wouldn’t have remained online.”

The Syrian Observatory for Human Rights, an antigovernment activist group, said it believed “the reason for the blackout was military operations being carried out by the regime forces in some areas.”

The failure had the least effect on rebel-controlled territories, where the Syrian opposition has successfully built an alternate system of Internet and cellphone connectivity using two-way satellite devices.

But the failure did temporarily silence the usually boisterous Syrian Electronic Army, the collective of pro-government Syrian hackers who have been breaking into the Twitter accounts of an array of news outlets and nonprofits, including E! Online,”The Onion,” Human Rights Watch and the Associated Press in recent weeks.

On Wednesday morning, one hacker affiliated with Syrian Electronic Army, who identified himself only by his hacker handle,Th3 Pr0, said he did not believe the government was to blame for the failure and that the electronic army’s campaign of targeting media outlets would continue.