tl;dr It’s unclear. Even if they do, it’s not the opinion of every U.S. intelligence agency.
The Washington Post, not necessarily a bastion of quality journalism these days, recently posted an article with an extraordinary claim as a headline: “Secret CIA assessment says Russia was trying to help Trump win White House“!
If you read through the article, that’s not quite what happened. The headline is (unsurprisingly) sensationalized.
CIA agents supposedly held a secret meeting with some members of Congress about a secret report on alleged Russian interference with the U.S. election. Agents were said to have potentially “identified individuals with connections to the Russian government who provided WikiLeaks with thousands of hacked emails from the Democratic National Committee and others.” Those individuals are not employed by the Russian government and may not have direct ties to the Kremlin. The CIA further claimed “it was now ‘quite clear’ that electing Trump was Russia’s goal,” according to the report. It’s important to note that the Washington Post’s article is not based on statements from the CIA. It’s based on statements from someone (likely a member of Congress) who attended the “secret meeting” or read a Senate-written summary about it. Therefore, this is all second-hand unverified information.
The New York Times ran a similar story, seemingly using another source (of course, also anonymous). The source said “We now have high confidence that [Russia] hacked the DNC and the RNC, and conspicuously released no documents [from the RNC hack].” This seems to be the basis of the “Russia helped Trump” claim. Meanwhile, there is no proof that the RNC was hacked. The RNC denied that their systems were breached, saying the FBI had personally reviewed RNC cybersecurity.
Many of the Wikileaks documents from government officials came from whistleblowers, FOIA requests, and unsophisticated phishing scams. It can also be argued that the contents of those documents and emails were more damaging than the leaks themselves. If so, Democratic officials would rather point fingers at a nuclear power (without proof) than accept personal responsibility for their own words and actions. Of course, cybersecurity is a serious issue and the source of alleged hacks should be discovered. That investigation is ongoing.
Craig Murray, the former UK ambassador to Uzbekistan, was quoted in the Guardian as saying the CIA claims were “bullshit.” Murray said he knew who gave information to Wikileaks, claiming that it was an ‘insider’ – who wasn’t Russian and wasn’t a hacker. He also said “America has not been shy about arresting whistleblowers and it’s not been shy about extraditing hackers. [The CIA] plainly [has] no knowledge whatsoever.” He believes that if the CIA really found out who performed the hackings, that person (or persons) would already be in an American prison.