The attacks have come in the form of simultaneously saying McMasters is anti-Israel and saying he's controlled by Jews.
https://www.theguardian.com/us-news/2017/aug/05/donald-trump-hr-mcmaster-israel-breitbart
The cartoon was later amended to crop out the Rothschilds hand.
https://www.theguardian.com/us-news/2017/aug/05/donald-trump-hr-mcmaster-israel-breitbart
Trump defends McMaster from far-right snipers
Terse statement follows attacks from bloggers and Breitbart and firings of three White House officials known to be allies of senior adviser Steve Bannon
Donald Trump has come to the defense of his national security advisor, HR McMaster, in the face of a sustained attack on the army general from the far right.
The president put out a short statement on Friday night which described McMaster as a good man, and said they were working very well together. But by Trumps standards it was a terse statement, unlikely to stem the flow of invective from the presidents own hardline supporters or resolve the factional conflict inside the White House.
Many of the attacks have come through the Breitbart News website, which was run until last August by Trumps in-house ideologue, Stephen Bannon. Breitbart stories described McMaster as increasingly volatile and said he frequent blows his top. Another headline said he was deeply hostile to Israel and to Trump.
The Trump statement, provided to White House reporters on Friday night, said: General McMaster and I are working very well together. He is a good man and very pro-Israel. I am grateful for the work he continues to do serving our country.
Breitbarts report on Trumps statement said the president had defied his base in defending his national security adviser, who it described as globalist, an insult from the point of view of the alt-right.
The anti-McMaster campaign was ignited by the firing of three White House officials known to be allies of Bannon and McMasters predecessor as national security advisor, retired general Michael Flynn.
Mike Cernovich, a far-right blogger who promoted conspiracy theories about Hillary Clinton during the campaign, posted an antisemitic cartoon showing McMaster as a puppet having his strings pulled by George Soros, a liberal Jewish philanthropist, who was in turn being controlled by another hand labelled Rothschilds.
The cartoon was later amended to crop out the Rothschilds hand.