Plc said a recent data breach occurred when an “unauthorized party” impersonated a trusted contact to dupe an employee at the online fashion retailer into handing over log-in details for their work account.

The hackers, calling themselves the Xuanye Group, then used those credentials to access information on certain third-party platforms used by Asos, the UK company said Thursday in an update to customers.

The affected platforms have been locked down and a full investigation has been launched, Asos said, adding that the website and app remain safe to use. The hackers have access to some personal information, including names and contact details, but no payment card information or account passwords were accessed, it said.

Shares of Asos rose as much as 5.3% in London on the news that the attack was not as widespread as initially feared.

Earlier this week, Asos shares plunged after users of its shopping app received a push notification threatening to leak data. The hackers claimed in the message that they had also compromised Asos’s Snowflake system, a cloud-based platform used to store large repositories of data. At the time they did not provide any evidence to support their claims, and a spokesperson for Snowflake Inc. later said its platform had not been breached.

There have been no further updates posted by the hackers since Tuesday. The UK Information Commissioner’s Office said it had been notified of a breach by Asos and is assessing the situation.

British retailers have suffered a number of cyberattacks in the past year, with sophisticated cybercrime groups like ShinyHunters targeting large organizations to steal data. Marks & Spencer Group Plc endured months of disruption after an attack last year forced it to pause online clothing and home orders.

Xuanye Group has not previously been associated with cyberattacks or data breaches and appears to have newly created its Telegram channel to promote its claimed compromise of Asos.