State Dept. has yet to clear its computer network of hackers: WSJ

- Three months after the U.S. State Department confirmed hackers breached its unclassified email system, the government has still not been able to evict them from the network, the Wall Street Journal reported on Thursday, citing three people familiar with the investigation.

Government officials, assisted by outside contractors and the National Security Agency, have repeatedly scanned the network and taken some systems offline, the Journal reported. But investigators still see signs of the hackers on State Department computers, the people familiar with the matter told the paper.

Each time investigators find a hacker tool and block it, the intruders tweak it slightly to attempt to sneak past defenses, the Journal reported. It is not clear how much data the hackers have taken.

No official determination has been made about who is behind the breach, which was disclosed in November, the paper said.

The Journal reported that five people familiar with the original intrusion said they had seen or been told of links suggesting involvement by the Russian government.

The malware, or intrusion software, is similar to other tools linked to Moscow in the past, the paper said. Two of the people said the intruders had taken State Department emails related to the crisis in Ukraine, among other things, the Journal reported.