South Korean defense company Korea Aerospace Industries paid Cohen $150,000 in November 2017.
The company, which is partly owned by the South Korean government's Export-Import bank, confirmed the payment and claimed the money was for "legal consulting concerning accounting standards on production costs."
It was a one-time payment that came at the end of contact with Essential, the firm said.
Korea Aerospace is currently partnered with Lockheed Martin on a bid to win a US Air Force contract. The contract winner would supply the Air Force with training aircraft and receive up to $16.3 billion.
AT&T paid Cohen at least $200,000 in four installments from late 2017 to early 2018.
The telecom giant confirmed the payment and said Cohen was paid to help AT&T better understand the Trump administration.
"Essential Consulting was one of several firms we engaged in early 2017 to provide insights into understanding the new administration," AT&T said in a statement Tuesday evening. "They did no legal or lobbying work for us, and the contract ended in December 2017."
AT&T is currently in the midst of a legal battle with the Trump administration over a proposed merger with Time Warner.
A source told CNBC on Wednesday that AT&T may have paid Cohen up to $600,000, but said it "wasn't to pay for access to the president."