Zoom Critical Vulnerability by GAIS Cyber Security

Teknologiia Lebanon
4 min readMay 29, 2020

With the COVID-19 pandemic, social life standards and habits have changed rapidly in the world, while different needs have emerged in the corporate and private sectors. At the beginning of these needs, in the face of this extraordinary situation, it directed the companies to video conference applications in order to get a quick reaction and normalize their business processes.

It has been determined by Gais CERT and Gais Cyber Intelligence that more than 500.000 personal and corporate Zoom accounts were leaked on Dark Web and illegal forum sites. While some of the leaked accounts were made accessible to everyone, some of them were sold for a fee.

Zoom application has been analyzed by the Gais Security to demonstrate that it is a common video conference application that is popular in many sectors in order to meet the needs of the companies and what are the risks of using these solutions will pose in possible security breaches. The vulnerability resulting from the analysis was shared with the Zoom officials and a $1000 award was given.

All details regarding the vulnerability detected in the analysis made by the Gais Security were shared with Zoom officials and the related vulnerability was quickly fixed. However, since the measures taken did not ensure the security of the meetings previously created, the report was shared with the end-user security in mind and in order to dimension the risk. Sharing the details of the vulnerability with the Zoom company officials by the Gais Security prevented the data of hundred thousands of users from leaking.

It was determined that detailed information about random id numbers generated by users called as “Personal Meeting” and “Other Meeting” or in randomly generated id numbers can be extracted in a directory we detected by applying fuzzing operations in the web service of the Zoom application.

Other Meeting

In this category, it has been determined that the subject parts of the meeting rooms that are live or past, the UserId number of the user who created it and the “meeting endpoint” information in the user’s local database are accessed.

Personal Meeting

In this category, it was observed that Zoom application caused sensitive data disclosure due to the lack of mandatory password usage while creating the security architecture. As a result of fuzzing “Personal Meeting” numbers produced with random numbers between 9 and 11 digits, it was determined that the passwords of the future meeting records, in which users are assigned as “Schedule Meeting” were accessed. In brute force attacks on meeting id values at the relevant address, meeting information and password information for hundred thousands of personal and corporate accounts were accessed.

We can list the security measures taken with the notification of the related weakness as follows;

• Assigning a password to the “Personal Meeting” id number when a new user is created after May.

• Mandatory password assignment when creating “Schedule Meeting”.

• New users who attend the meetings are not included in the video conference system until being approved by the moderator.

• Applying masking process to sensitive information on the web application.

It has been reported to Zoom officials that this detected security vulnerability continues to affect hundreds of thousands of users, which opened before May and did not assign passwords to “Personal Meeting” addresses.

The report was taken from https://gaissecurity.com/

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