Won't You Be My Neighbor?

A common metaphor for the Internet is that it’s divided into neighborhoods. If your website is hosted on an IP address and using nameservers that allow or encourage criminal activity, then you’re in a “bad neighborhood”. Bad neighborhoods can exist because some hosting providers offer a space for criminals to set up domains to serve malicious content to visitors.  Under these circumstances, the hosting providers turn a blind eye as long as they are making money.  Another contributing factor that creates bad neighborhoods are compromised hosts used maliciously without the owners knowledge.

We’re going to take a walk through one of these bad neighborhoods in this blog post.

Enter at the Gate

Our introduction to this neighborhood began when we were alerted to network communications with a URL ending in ‘gate.php’. URLs ending in ‘gate.php’ are indicative of default C2 URL configurations for multiple botnet families; ZeuS, Andromeda, and Pony downloader.
Network communications:
http://exportproducts[.]se/axump/gate[.]php

This particular one looks to be AZORult. AZORult steals credential and credit card/payment information. Researchers have seen it involved in attack campaigns with Chthonic and Ramnit.

Once we started to look at the infrastructure behind this, the nameservers stood out as suspicious. The nameservers are: ns1[.]steeldns[.]com and ns2[.]steeldns[.]com. A suspicious feature here is that the parent domain points to: localhost and 127.0.0.1.

Furthermore, the TTL (Time To Live) change frequently on both nameservers; rotating between low-high values. DNS responses with low TTL values are indicative of Fast Flux botnets. In conjunction with compromised hosts acting as proxies, it creates a resilient command and control infrastructure. The multiple nodes or hosts within the network register and de-register their addresses as part of the DNS A record, changing the IP addresses. Each record has a very short TTL. This creates a constantly changing list of IP addresses for a domain name.

This particular host is consistently changing to a low TTL, but not changing the IP address. It doesn’t appear they’re successfully utilizing a Fast Flux technique, but it’s enough to appear suspicious.

A co-occurrence for ns1[.]steeldns[.]com is another nameserver ns2[.]metaldns[.]com. A co-occurrence is when two or more domains are being accessed by the same users within a small window of time.  This top domain, metaldns[.]com is also pointed to localhost 127.0.0.1.

Thanks to our passive DNS data, we have domain names that we’ve seen resolving to the IP addresses of these suspicious nameservers. The following are a few interesting sights seen in this neighborhood while crawling through the domains found.

Lots of Open Space

There are plenty of open directories that lead to various phishing pages and kits.

Phishing Pond

If you continue down the walking path from the open space, you’ll make your way to the local phishing pond.