Jared Kushner walks out after President Trump spoke at the White House on May 18.
"With respect to the news about his permanent security clearance, as we stated before, his application was properly submitted, reviewed by career officials, and went through the normal process", Lowell continued.
Kushner's permanent clearance was granted after career officials completed the Federal Bureau of Investigation background check process, according to the person familiar with the matter, who spoke on the condition of anonymity because of the sensitivity of the situation.
Citing officials familiar with the matter, CNN did not detail Kushner's level of clearance or what caused law-enforcement authorities to grant it.
Lowell, in a statement, said Kushner has cooperated fully with the investigation, including sitting for two interviews with the special counsel's office.
White House Chief of Staff John Kelly had ordered changes to the clearance system after a top aide - Rob Porter - worked for months without full clearance because of allegations he abused both his former wives.
Kushner subsequently amended the form once again after it was revealed that he met with Russian attorney Natalia Veselnitskaya, who had met with him based on the promise that she had damaging information on Democratic presidential nominee Hillary Clinton.More news: Russia-Germany gas pipeline raises intelligence concerns
Abbe Lowell, who has represented Kushner in the Russian Federation investigation, told CNN's Wolf Blitzer that questions asked of Kushner during the April interview were "the appropriate topics that Bob Mueller and his team were looking at".
Lowell said that Kushner answered all questions that were asked.
"For that job, he would normally need top secret and SCI", Zaid said.
Kushner's months-long inability to get a permanent security clearance had long vexed the administration, so much so that some officials felt unwilling to push the issue with others in similar straits.
Whether the restoration of Kushner's clearance is somehow related to his cooperation with Mueller is not immediately clear. White House officials were adamant that the lengthy process was not unusual for a government official who has a complicated financial history and many foreign contacts.
Kushner was with Trump in New Jersey the weekend before Comey was sacked, and he was among the attendees at a June 2016 meeting at Trump Tower with a Russian lawyer at which the president's oldest son was told he would negative information about Hillary Clinton.