Microsoft has won a court order to gain control of 23 No-IP domains owned by dynamic DNS (DDNS) provider Vitalwerks Internet Solutions. The US software giant claimed the domains were being used by malware developed in the Middle East and Africa.

Vitalwerks operates its No-IP DDNS service from Nevada, and there is no suggestion it is in league with malware operators.

The service works by mapping users' IP addresses, such as a home router's public address, to a customized No-IP domain-name like myhouse.ddns.net . This allows you to connect to a system using a memorable sub-domain if you forget your IP address or your ISP changes it.

Microsoft's security research team claimed it had identified two pieces of Windows malware, Bladabindi and Jenxcus, using No-IP sub-domains to communicate with their creators in 93 per cent of detected infections, and that 245 other pieces of malware also use No-IP.

"Despite numerous reports by the security community on No-IP domain abuse, the company has not taken sufficient steps to correct, remedy, prevent or control the abuse or help keep its domains safe from malicious activity," claimed Richard Boscovich, assistant general counsel of Microsoft Digital Crimes Unit.

Court papers filed in Nevada alleged that Bladabindi was written by Naser Al Mutairi, a Kuwaiti national, while Jenxcus is allegedly run by an Algerian man named as Mohamed Benabdellah. Microsoft claimed the two have sold over 500 copies of the malware to crooks, and actively advertise it while using No-IP to help cover their tracks. The software giant said it has detected over seven million infections by the two packages.

The court has now granted a temporary restraining order against No-IP – as Microsoft accused the DNS biz of acting negligently, and claimed some of the sub-domains contained "Microsoft’s protected marks."

Redmond further alleged that the defendants in its lawsuit – Al Mutairi, Benabdellah, Vitalwerks and 500 John Does – "violated federal and state law by distributing malicious software through more than 18,000 sub-domains belonging to No-IP, causing the unlawful intrusion into, infection of, and further illegal conduct involving, the personal computers of innocent persons, thereby causing harm to those persons, Microsoft, and the public at large."

Thus, by order of the court, DNS traffic for the domains is now being funneled through Microsoft's servers – ns7.microsoftinternetsafety.net and ns8.microsoftinternetsafety.net – where requests are filtered for hostnames [PDF] associated with malicious activity. Redmond says that this is the first time the company has taken action against botnets that have been operated outside of Europe.

No-IP in firing line again

This isn't the first time the No-IP service has been fingered for providing a backchannel for malware operators. In February, Cisco published data showing a huge amount of malware traffic was flowing via Vitalwerks DNS servers.

Today's successful court action was met with dismay from No-IP parent company Vitalwerks. Spokeswoman Natalie Goguen told The Register that Microsoft didn’t contact it before the takeover, and the first the company knew about the court action was when the papers were delivered to the CEO over breakfast today, and millions of its customers are now without service.

"We have around four million users affected by this outage, people who are doing great things with the service," she said. "Microsoft was supposed to filter out the malware traffic and leave the good traffic but apparently their servers couldn't handle it."

Goguen said her company does its best to filter out malicious traffic from its DNS servers – although with just 14 employees its abilities are somewhat limited. It added that it is happy to work with other companies to stop people using its service illegally.

Microsoft told El Reg that, due to the ongoing legal action against the firm and the two malware writers, it was unable to comment on the allegations from Vitalwerks about the outage.

Redmond has instead confined its comments on the case to two blog posts and an infographic. ®