Dhaka, July 24 -- A cyber-espionage campaign centred on vulnerable versions of Microsoft's server software now involves the deployment of ransomware, Microsoft said in a late Wednesday blog post, opens new tab.

In the post, citing "expanded analysis and threat intelligence," Microsoft said a group it dubs "Storm-2603" is using the vulnerability to seed the ransomware, which typically works by paralysing victims' networks until a digital currency payment is made.

The disclosure marks a potential escalation in the campaign, which has already hit at least 400 victims, according to Netherlands-based cybersecurity firm Eye Security. Unlike typical state-backed hacker campaigns, which are aimed at stealing data, ransomware can cause widesprea...