SAN FRANCISCO – Hackers have stolen data from the systems of a number of users of the popular file transfer tool Moveit Transfer, United States security researchers said on Thursday.

This came one day after the maker of the software disclosed that a security flaw had been discovered.

After disclosing the vulnerability on Wednesday, Progress Software said it could lead to potential unauthorised access into users’ systems.

The managed file transfer software made by the Burlington, Massachusetts-based company allows organisations to transfer files and data between business partners and customers.

It was not immediately clear which or how many organisations use the software or were affected by potential breaches. Chief information officer Ian Pitt declined to share those details, but said Progress Software had made fixes available since it discovered the vulnerability late on May 28.

The software’s eponymous cloud-based service had also been affected, he told Reuters.

“As of now we see no exploit of the cloud platform,” he said.

Cyber-security firm Rapid7 and Mandiant Consulting – owned by Alphabet’s Google – said they had found a number of cases in which the flaw had been exploited to steal data.

“Mass exploitation and broad data theft has occurred over the past few days,” Mandiant Consulting chief technology officer Charles Carmakal said in a statement.

Such “zero-day”, or previously unknown, vulnerabilities in managed file transfer solutions have led to data theft, leaks, extortion and victim-shaming in the past, Mandiant said.

“Although Mandiant does not yet know the motivation of the threat actor, organisations should prepare for potential extortion and publication of the stolen data,” Mr Carmakal said.

Rapid7 said it had noticed an uptick in cases of compromise linked to the flaw since it was disclosed.

Progress Software has outlined steps users at risk can take to mitigate the impact of the security vulnerability.

Mr Pitt did not have a comment on who might have been trying to steal data by exploiting the flaw.

“We have no evidence of it being used to spread malware,” he said.

Moveit Transfer was used by a relatively small number of customers compared with those of the company’s more than 20 other software products, he said.

“We have forensics partners on board, and we are working with them to make sure that we have an ever-evolving grasp of the situation.” REUTERS