The US Senate has become the latest organization to tell its members not to use Zoom because of concerns about data security on the video conferencing platform that has boomed in popularity during the coronavirus crisis.

The Senate sergeant at arms has warned all senators against using the service, according to three people briefed on the advice.

One person who had seen the Senate warning said it told each senator’s office to find an alternative platform to use for remote working while many parts of the US remain in lockdown. But the person added it had stopped short of officially banning the company’s products.

Zoom is battling to stem a public and regulatory backlash over lax privacy practices and rising harassment on the platform that has sent its stock plummeting. The company’s shares have fallen more than 25 per cent from highs just two weeks ago, to trade at $118.91.

Zoom was forced to apologize publicly last week for making misleading statements about the strength of its encryption technology, which is intended to stop outside parties from seeing users’ data.

The company also admitted to “mistakenly” routing user data through China over the past month to cope with a dramatic rise in traffic. Zoom has two servers and a 700-strong research and development arm in China. It had stated that users’ meeting information would stay in the country in which it originated.

The revelations triggered complaints from US senators, several of whom urged the Federal Trade Commission to investigate whether the company had broken consumer protection laws. It also prompted the Taiwanese government to ban Zoom for official business.

The FBI warned last month that it had received reports that teleconferences were being hacked by people sharing pornographic messages or using abusive language — a practice that has become known as “Zoombombing.”

A spokesperson for the company said: “Zoom is working around-the-clock to ensure that universities, schools, and other businesses around the world can stay connected and operational during this pandemic, and we take user privacy, security and trust extremely seriously.

“We appreciate the outreach we have received on these issues from various elected officials and look forward to engaging with them.”

However, the US Department of Homeland Security said in a memo to government cyber security officials that the company was actively responding to concerns and understood how grave they were, according to Reuters. The Pentagon told the Financial Times it would continue to allow its personnel to use Zoom.

The Senate move follows similar decisions by companies including Google, which last week decided to stop employees from downloading the app for work.

“Recently, our security team informed employees using Zoom Desktop Client that it will no longer run on corporate computers as it does not meet our security standards for apps used by our employees,” Jose Castaneda, a Google spokesperson, said. However, he added that employees wanting to use Zoom to stay in touch with family and friends on their mobiles or via a web browser could do so.

The Google decision was first reported by BuzzFeed.

Zoom has tried to stem the tide of criticism in recent days. The company said on Wednesday it had hired Alex Stamos, the former Facebook security chief, as an outside security consultant, days after saying it would redirect its engineering resources to tackle security and privacy issues.

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