Russian government hackers penetrated the computer network of the Democratic National Committee and gained access to the entire database of opposition research on GOP presidential candidate Donald Trump, according to committee officials and security experts who responded to the breach.

The intruders so thoroughly compromised the DNC’s system that they also were able to read all email and chat traffic, said DNC officials and the security experts.

The intrusion into the DNC was one of several targeting American political organizations. The networks of presidential candidates Hillary Clinton and Donald Trump were also targeted by Russian spies, as were the computers of some GOP political action committees, U.S. officials said. But details on those cases were not available.

A Russian Embassy spokesman said he had no knowledge of such intrusions.

This Looks Like the DNC’s Hacked Trump Oppo File

Some of the hackers had access to the DNC network for about a year, but all were expelled over the past weekend in a major computer cleanup campaign, the committee officials and experts said.

The DNC said that no financial, donor or personal information appears to have been accessed or taken, suggesting that the breach was traditional espionage, not the work of criminal hackers.

“The security of our system is critical to our operation and to the confidence of the campaigns and state parties we work with,” said Rep. Debbie Wasserman Schultz (D-Fla.), the DNC chairwoman. “When we discovered the intrusion, we treated this like the serious incident it is and reached out to CrowdStrike immediately. Our team moved as quickly as possible to kick out the intruders and secure our network.”

They had access for about a year, but they moved fast to kick them out. The stupidity is astounding here.