Cybersecurity researchers fear Chinese telecom hack Hackers waged a campaign from 2017 to 2021, in some cases exploiting vulnerabilities in Microsoft Corp's Exchange servers to access telecom firms' internal systems Chinese hacking groups have compromised global telecommunications companies by stealing phone records and location data, cybersecurity researchers said. The hacking groups waged a campaign from 2017 to 2021, in some cases exploiting security vulnerabilities in Microsoft Corp’s Exchange servers to gain access to telecommunication companies’ internal systems, according to a new report published on Tuesday by US-based security firm Cybereason Inc. Advertisement The report did not name any telecom firms, while a response from Cybereason on any impact in India is awaited. However, the firm said the attacks were primarily across Southeast Asian countries.