Tencent weChat, a popular messaging app, is one of the most popular in China, with almost 90% of users saying they use it for free.
WeChat has a similar number of users in the United States, where it is second only to Facebook.
Google also offers a version of the app, but it has no significant users.
Wechat has been one of China’s most popular messaging apps since it launched in late 2014.
In early 2016, a hacker known as “DuoX” released a virus that took control of a popular WeChat app, and it was the only app to be shut down in the country.
Weibo, the social media service that is the official Chinese version of Twitter, is another popular messaging application.
Both of these apps are frequently used in China.
Google declined to comment on whether it was aware of the malicious code, and Tencent did not respond to requests for comment.
Facebook declined to respond to the article.
Apple also declined to answer a question about the nature of its messaging apps in China by email, but said that it uses Chinese developers to provide translations into English for its users.