The National Health Surveillance Agency (Anvisa) said on Monday that it blocked Zoom's video conferencing tool on the municipality's computers, citing the possibility of security breaches on the platform.
Anvisa reported that its technology team identified, through specialized websites on the subject, vulnerabilities in Zoom's platform that "allow unauthorized access to the user's camera and microphone, enabling the theft of credentials and information exchanged" in videoconferences.
Zoom's chief executive said in a note to Anvisa that the company is applying security patches to its systems, according to the agency, which will reevaluate the use of the tool after the updates.
The platform saw a jump to more than 200 million daily users in March, from a previous record of 10 million in December, amid the adoption of remote work and online classes during the coronavirus pandemic, propelling the company's shares to a record high. .
However, several reports questioning the company's data privacy practices have emerged and have scared investors.
Last week, SpaceX banned its employees from using the platform, just as some US school districts banned its use in the face of growing security concerns.
On Monday afternoon, Zoom's shares were down about 6.5%, while the Nasdaq index rose 5.45% and the Dow Jones appreciated 5.75%.
Credit Suisse downgraded the company's shares from "neutral" to "underperfom", citing the possible difficulty in monetizing new free and educational customers after complaints.
"Concerns about cryptography have already caused some high-profile customers to restrict their use of Zoom, and we hope others can follow, although most organizations are likely to have no problems," said Credit Suisse analysts.
(With additional reporting by Akanksha Rana in Bangalore, India)