(Bloomberg) -- Executives from Alibaba Group Holding Ltd.’s cloud division have been summoned for talks by authorities in Shanghai in connection with the theft of a vast police database, the Wall Street Journal reported, citing people familiar with the matter. 

China has been rocked in recent weeks by one of the largest cybersecurity breaches in the country’s history. Hackers claimed to have stolen data on as many as a billion Chinese residents after penetrating a police database. The person or group claiming the attack offered to sell the information online for the equivalent of about $200,000. 

According to the Journal, cybersecurity researchers said a dashboard for managing the database had been left open without a password for more than a year, making it easy to steal and erase its contents.

Based on scans of the database, the researchers concluded that it was hosted on Alibaba’s cloud platform, according to the Journal. Company employees also confirmed the relationship, the paper said. The Chinese tech giant has been conducting an internal investigation into how the heist was allowed to happen, the newspaper reported. 

Executives called in for meetings with the Shanghai authorities include Alibaba Cloud Vice President Chen Xuesong, who was recently hired to lead the unit’s digital public-security business, the Journal said, citing people familiar with the matter.

An Alibaba representative in the US didn’t immediately respond to a request for comment. Alibaba’s American depositary receipts fell 5.1% in New York.

(Updates with no immediate response from Alibaba)

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