An internal White House memo written by a senior cybersecurity official at the time, obtained by Axios, warned: "The White House is posturing itself to be electronically compromised once again."

The cybersecurity staffer Dimitrios Vastakis wrote in the memo, which Axios said also served as a resignation letter, that this was because the White House had diminished the power of the Office of the Chief Information Security Officer, a cybersecurity unit set up after a 2014 cyberattack.

President Donald Trump's administration has pushed out multiple cybersecurity officials by decreasing their responsibilities and revoking their access to buildings, among other things, according to the memo.

Visit Business Insider's homepage for more stories.

An internal memo has warned that the White House could be hacked again because so many cybersecurity officials have resigned or been pushed out under President Donald Trump's administration, Axios reported Wednesday.

"I foresee the White House is posturing itself to be electronically compromised once again," wrote Dimitrios Vastakis, a branch chief of the White House computer network defense unit, in the October 17 memo obtained by Axios.

Business Insider could not independently verify the memo's authenticity.

Vastakis said this was because the White House had been gradually diminishing the responsibilities and power of the Office of the Chief Information Security Officer, which was set up in 2014 after hackers accessed an unclassified computer network used by President Barack Obama's office.

The hackers, who were reportedly working for the Russian government, had used a phishing-style attack on the State Department to gain access to the White House network. Through the cyberattack they managed to obtain sensitive information such as Obama's daily schedule.

President Barack Obama with an Apple iPad during a visit to Buck Lodge Middle School in Adelphi, Maryland, in 2014. REUTERS/Kevin Lamarque

The Trump administration in July folded the office into the Office of the Chief Information Officer, Axios reported, which diminished the former office's power and responsibilities at the White House.

At least a dozen of top- or high-level officials from the former office have resigned or been pushed out since, Axios reported. The memo also served as Vastakis' resignation letter, Axios said.

Vastakis said in his memo that remaining employees from the former office were "systematically being targeted for removal" by having their duties diminished, access to buildings revoked, and decision-making power taken away.

"Allowing for a large portion of institutional knowledge to concurrently walk right out the front door seems contrary to the best interests of the mission and the organization as a whole," Vastakis wrote.

Axios also cited an anonymous White House source familiar with the moves as saying: "You have an entire section who's dedicated to providing counter threat intelligence information."

"If you remove that, it's like the Wild West again."

Read the full memo here. The White House has not yet responded to Business Insider's request for comment on Vastakis' allegations or whether the memo published by Axios was legitimate.

White House

Read more: The White House 'lockdown' of Trump's call with Ukraine looks like part of a bigger, worrying pattern

Questions about White House computer systems have come to light in recent weeks after an intelligence-community whistleblower said officials locked away potentially embarrassing — but not sensitive — transcripts of Trump's phone calls in restricted computer system reserved for information that could jeopardize national security.