Stone said he could be under investigation by special counsel Robert Mueller for alleged crimes unrelated to his role in the 2016 presidential election.
The federal ethics office flagged the disclosure in a letter to Deputy Attorney General Rod Rosenstein.
As he headed to Dallas for the NRA convention, the president told reporters Friday morning that his new attorney Rudy Giuliani "will get his facts straight."
The deputy attorney general used a Law Day appearance in Washington to defend himself and the Justice Department from a pressure campaign waged by Trump allies.
While the bill lacks support from GOP leaders in the House and Senate, it's intended to send a message to President Trump that he avoid interfering with special counsel Robert Mueller's investigation.
The former FBI director's favorability ratings dropped a net of 11 percentage points overall since last month, as Trump and conservatives ratcheted up attacks on the ongoing investigation.
NPR confirms that the president's legal team was notified last month that he wasn't a criminal target at the time but is being investigated.
John Dowd recently said the special counsel's Russia investigation should be shut down. He is now leaving, saying, "I love the president and wish him well."
Congressional Republicans would not go as far as the president. Sen. Marco Rubio said he remained confident that special counsel Robert Mueller is "fair and thorough" and will "arrive at the truth."
President Trump spent much of the weekend on Twitter criticizing the investigation into Russian interference in the 2016 election, calling it unnecessary and partisan.