WaPo:

U.S. intelligence agencies warned the White House last year that President Trump’s personal lawyer Rudolph W. Giuliani was the target of an influence operation by Russian intelligence, according to four former officials familiar with the matter.

The warnings were based on multiple sources, including intercepted communications, that showed Giuliani was interacting with people tied to Russian intelligence during a December 2019 trip to Ukraine, where he was gathering information that he thought would expose corrupt acts by former vice president Joe Biden and his son Hunter.

The intelligence raised concerns that Giuliani was being used to feed Russian misinformation to the president, the former officials said, speaking on the condition of anonymity to discuss sensitive information and conversations.

The warnings to the White House, which have not previously been reported, led national security adviser Robert O’Brien to caution Trump in a private conversation that any information Giuliani brought back from Ukraine should be considered contaminated by Russia, one of the former officials said…

Several senior administration officials “all had a common understanding” that Giuliani was being targeted by the Russians, said the former official who recounted O’Brien’s intervention. That group included Attorney General William P. Barr, FBI Director Christopher A. Wray and White Counsel Pat Cipollone.