Microsoft's seizure of domains from a DNS service provider has also disrupted some state-sponsored cyberespionage campaigns, according to security vendor Kaspersky Lab.
A quarter of the long-term malware operations run by hacking groups tracked by the Russian security vendor have been affected by the seizure of domains from No-IP, wrote analyst Costin Rau on a company blog Tuesday.
No-IP, run by Nevada-based Vitalwerks, has a free "dynamic DNS" service that updates DNS entries for a domain that has a changing IP address assigned by an ISP. It does that by lending a subdomain to the customer, then updating the DNS record as the IP address for the hostname changes.
With a federal court order, Microsoft seized 22 domains used by No-IP for its service on Monday, alleging two men in Algeria and Kuwait used No-IP's service as part of the infrastructure for a botnet. It alleged no wrongdoing by No-IP but said it was lax in responding to abuse.
Microsoft alleged the men used No-IP to create points of contact for infected machines in order to receive instructions. The command-and-control infrastructure for their alleged operation had dynamic IP addresses, according to the civil lawsuit.
Microsoft "sinkholed" those domains, blocking the malicious traffic, although it made a technical error and cut off some of No-IP's legitimate customers.
Although Microsoft was taking aim at two malware families called Bladabdindi and Jenxcus that employed No-IP, Rau wrote the seizure has had a larger impact on so-called APT (advanced persistent threat) campaigns, which are long-running infiltration operations often run by nation states.
Computers used in these campaigns "are now pointing to what appears to be a Microsoft sinkhole," Rau wrote.
The malware includes Flame, which was found on computers in Iran and other Middle Eastern countries, and the Italian company Hacking Team's Remote Control System, which is spying software intended for use by law enforcement.
Other malware that may be affected include Turla/Snake/Urobos/Epic, Cycldek, Shiqiang, Banechat and Ladyoffice, Rau wrote.
Hacking groups are now likely to be more careful when using dynamic DNS providers and rely more on hacking websites and direct IP address changes to manage their command-and-control infrastructure, Rau wrote.
Send news tips and comments to [email protected] Follow me on Twitter: @jeremy_kirk