“The five-day system failure may be beyond many people's expectations, especially now that many stores have been closed during the epidemic and mainly rely on their online businesses,” said Dong Zhiyi, a lawyer at Shanghai Joint-Win Law Firm and researcher at the China E-commerce Research Center.

“So under the double blow, the impact is very serious.”

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In a subsequent statement on Thursday, Weimob’s founder and chief executive Sun Taoyong said that he was angry but felt “sympathy” for the employee responsible after learning from the police that the latter was mired in debt and had considered suicide, and was distressed over being stuck at home alone for 30 days due to the coronavirus lockdowns.

Sun said the employee had always performed well and his colleagues saw him as dependable, so when they traced the attack back to him the company’s first suspicion was that his credentials could have been stolen.

“We survived the ‘natural disaster’ [of the coronavirus outbreak] but unexpectedly a ‘human disaster’ put us in an extremely difficult situation,” Sun said.

Weimob said in the filing that it is working on compensation plans for merchants who suffered losses due to the outages.

New users would have been able to use the company’s services as normal from Wednesday and existing users will have their data restored by midnight on Friday, it said, adding that it would provide a temporary transition plan for existing users before the system is fully restored.

For the first six months of 2019, Weimob reported a total revenue of 656.7 million yuan (US$93.7 million), of which revenue from its software-as-a-service (SaaS) business was 219.1 million yuan (US$31.2 million), or about 33.4 per cent.

The company’s board expects the outages caused by the employee’s actions to damage operations of its SaaS business, but not its other business segments, it said in the filing.