Tag Archives: threshold

What’s Under that Threshold?

This blog post is meant to be short, sweet and to the point so please forgive the brevity if you were looking for something in depth this time….

*THE LITTLE FISH*

Many of us are trained to get the big fish, find the next cutting edge threat, defend against the big blob of red in the graphic of some ridiculous C-level slide presentation. We sit, eyes locked on some SOC tool waiting for bells & whistles to go off, the emails to start flying, the lights to flash to wake us up because we’ve fallen asleep from boredom all because we’ve place our trust in a tool to tell us on what we should focus our attention. So, how often do you go digging, or lift up the lid on something peeking to see what’s inside? What are you doing about the quiet, smart bad guy who’s tiptoeing in just under your alert criteria? You know, the one who isn’t making a lot of noise on your network, the customer doing the dirtiest of deeds, just under your thresholds for your automated alarms?

*MY GLORIOUS TOOLS*

Well, if you know what your thresholds are for automated alerts, why aren’t YOU looking at what lies beneath it? Is it because you think nobody with malicious intent would take the time to do X in such small quantities because it wouldn’t pay off? Is it because your tool is awesome and perfect *cough*cough*cough*cries*grabs water*? If you answered yes, to the 2nd or 3rd question please allow me to share some good ol’ country advice that has served me well is “He who underestimates his enemy, has lost the first battle in the war.”

*MY CUSTOMER?! NOT _MY_ CUSTOMER*

So without divulging the details to my current research, I’ll share a few things I’ve been noticing lately. First is bad guys doing a little here, a little there regarding purchasing domains. Instead of buying in bulk, they’re buying a few each day at a time. So, if you’re selling domains, maybe you want to take a look at any customers who are buying in quantities just below your “alarm” threshold and who are NOT buying via your bulk discount programs. I mean seriously, what does one individual need with a couple hundred domains, that he/she wouldn’t want to take advantage of bulk discounts? I mean, they could just be a legit business that doesn’t know any better, but I’m gonna guess not. It might be worth checking those domains out using tools such as OpenDNS, Domain Tools, Threat Grid, and Virus Total. Are the domains registered, more than 30 days old and still do not have a websites? What’s the aggregate amount of domains purchased in the last 30 days and how old is the customer account? Does the data on the domain registrations, match that on your customer’s account? Does the data on the domain registration match ANOTHER customer account? If you find that your customer’s domains are popping hot, ya just might want to take a leeeetle-bit closer look at their activities.

Let’s look at another OSINT source you have….customer access logs. The second thing I’ve been noticing is bad guys creating DNS entries a little here, a little there. So you found a guy, flying below the radar (could be a girl, but just go with me here) with the daily number of domains being purchased under your alarm level. Maybe you provide infrastructure not domains, so you offer DNS, and you have a customer flying below the radar making lots of DNS records. Do your tools alert you when a customer logs into his/her account from multiple ASN’s or ASN’s in different countries? I mean if a guy logs in for <5 minutes, makes DNS records, and logs out all from from Romania on Sunday, Russia on Monday, Great Britain on Tues....etc either he's racking up some serious frequent flyer miles or he might be up to no good. AGAIN, there COULD be a perfectly legitimate explanation (none come to mind immediately) but you won't even know unless you go looking. If you're providing website hosting, do you have a customer that has hundreds of completely unrelated domains pointing to a single IP? I once found a guy with over 900 malicious domains all pointing/pointed to a single IP...I wanted to say to the provider "Seriously you don't notice?" *SUMMARY* So the point of today's topic - start looking BELOW your automated thresholds for the really bad guys. Be pro-active, stop waiting for bad guys to wave, shake your hand, and say hello. Thanks again for taking time to read the blog and feel free to share comments, DM me on twitter, or just tag and say hi!