Cybersecurity software provider Qualys Inc. is the latest victim of a data breach, as the Clop ransomware gang posted on its site screenshots of files allegedly belonging to the company.

Qualys confirmed the attack Wednesday, describing it as a “security incident” that exploited a previously identified vulnerability in software from Accellion Inc. to transfer information from the company’s customer support system.

The attack did not affect Qualys production environments, either shared or private platforms, as well as its codebase or customer data hosted on the Qualys Cloud Platform, Qualys Agents or Scanners.

The company didn’t state exactly when the theft of data took place, but it said its information technology team applied a hot fix to secure their Accellion FTA server on Dec. 22. Along with enhancing security measures by deploying additional patches and enabling additional alerting, it then received an integrity alert Dec. 24 and isolated the affected server from the network, later shutting it down.

Qualys also did not detail the types of data stolen, saying only that they immediately notified the “limited number of customers impacted by this unauthorized access.” Although Qualys claimed the data only came from a customer support system, Bleeping Computer reported that the data published by the Clop ransomware gang includes purchase orders, invoices, tax documents and scanned reports.

Data breaches targeting companies and organizations who were using the vulnerable version of Accellion FTA server have been regularly coming to light since the vulnerability was first detected. Victims include Bombardier Inc., Jones Day and the Office of the Washington State Auditor.

“Qualys’ response to the incident is a laudable example of transparent and professional handling of a security incident,” Ilia Kolochenko, founder and chief executive of web security company ImmuniWeb, told SiliconANGLE. “Under the integrity of currently disclosed circumstances, I see absolutely no reason for panic.”

Kolochenko thinks sensitive data such as vulnerability reports or customer passwords are almost certainly unaffected. “Thus, I’d definitely refrain from labeling the attack as a ‘breach’ but rather a security incident,” he said. “A third-party investigation will likely shed light on the situation and hopefully will bring even more assurance to Qualys customers.”

Image: Qualys