• Skip to primary navigation
  • Skip to main content
  • Skip to footer

Cisco Umbrella

Enterprise network security

  • Contact Sales
  • Login
    • Umbrella Login
    • Cloudlock Login
  • Why Us
    • Why Cisco Umbrella
      • Why Try Umbrella
      • Why DNS Security
      • Why Umbrella SASE
      • Our Customers
      • Customer Stories
      • Why Start a Free Trial
      • Why Cisco Secure
    • Fast Reliable Cloud
      • Global Cloud Architecture
      • Cloud Network Status
      • Global Cloud Network Activity
    • Unmatched Intelligence
      • A New Approach to Cybersecurity
      • Interactive Intelligence
      • Cyber Attack Prevention
      • Umbrella and Cisco Talos Threat Intelligence
    • Extensive Integrations
      • IT Security Integrations
      • Hardware Integrations
      • Meraki Integration
      • Cisco Umbrella and SecureX
  • Products
    • Cisco Umbrella Products
      • Cisco Umbrella Cloud Security Service
      • Recursive DNS Services
      • Cisco Umbrella SIG
      • Umbrella Investigate
      • What’s New
    • Product Packages
      • Cisco Umbrella Package Comparison
      • – DNS Security Essentials Package
      • – DNS Security Advantage Package
      • – SIG Essentials Package
      • – SIG Advantage Package
      • Umbrella Support Packages
    • Functionality
      • DNS-Layer Security
      • Secure Web Gateway
      • Cloud Access Security Broker (CASB)
      • Cloud-Delivered Firewall
      • Malware Protection
      • Remote Browser Isolation (RBI)
      • Data loss prevention (DLP)
    • Man on a laptop with headphones on. He is attending a Cisco Umbrella Live Demo
  • Solutions
    • SASE Solutions
      • Cisco Umbrella SASE
      • Secure Access Service Edge (SASE)
      • What is SASE
      • What is Security Service Edge (SSE)
    • Functionality Solutions
      • Web Content Filtering
      • Secure Direct Internet Access
      • Shadow IT Discovery & App Blocking
      • Fast Incident Response
      • Unified Threat Management
      • Protect Mobile Users
      • Securing Remote and Roaming Users
    • Network Solutions
      • Guest Wi-Fi Security
      • SD-WAN Security
      • Off-Network Endpoint Security
    • Industry Solutions
      • Higher Education Security
      • K-12 Schools Security
      • Healthcare, Retail and Hospitality Security
      • Enterprise Cloud Security
      • Small Business Cybersecurity
  • Resources
    • Content Library
      • Top Resources
      • Cybersecurity Webinars
      • Events
      • Analyst Reports
      • Case Studies
      • Customer Videos
      • Datasheets
      • eBooks
      • Infographics
      • Solution Briefs
    • International Documents
      • Deutsch/German
      • Español/Spanish
      • Français/French
      • Italiano/Italian
      • 日本語/Japanese
    • For Customers
      • Support
      • Customer Success Webinars
      • Cisco Umbrella Studio
    • Get the 2022 Cloud Scurity Comparison Guide
  • Trends & Threats
    • Market Trends
      • Hybrid Workforce
      • Rise of Remote Workers
      • Secure Internet Gateway (SIG)
    • Security Threats
      • Ransomware
      • Cryptomining Malware Protection
      • Cybersecurity Threat Landscape
      • Global Cyber Threat Intelligence
      • Cyber Threat Categories and Definitions
    •  
    • Woman connecting confidently to any device anywhere
  • Partners
    • Channel Partners
      • Partner Program
      • Become a Partner
    • Service Providers
      • Secure Connectivity
      • Managed Security for MSSPs
      • Managed IT for MSPs
    •  
    • Person looking down at laptop. They are connecting and working securely
  • Blog
    • News & Product Posts
      • Latest Posts
      • Products & Services
      • Customer Focus
      • Feature Spotlight
    • Cybersecurity Posts
      • Security
      • Threats
      • Cybersecurity Threat Spotlight
      • Research
    •  
    • Register for a webinar - with illustration of connecting securely to the cloud
  • Contact Us
  • Umbrella Login
  • Cloudlock Login
  • Free Trial
Research

Domain Generation Algorithms – Why so effective?

By Andrea Kaiser
Posted on October 10, 2016
Updated on March 4, 2020

Share

FacebookTweetLinkedIn

Domain Generation Algorithms(DGAs) are used in malware to generate a large number of domain names that can be used in communications to the malware’s command and control servers. One reason that DGAs are used is because a predefined list of domains that will be used as Command & Control (C&C) servers can be easily discovered in the binaries of malware. An algorithm needs to be reverse engineered. Some DGAs can be completely thwarted through reverse engineering, and every possible domain name can be known and then blocked through security layers. The majority of the domain names generated by DGAs do not resolve (NXdomains) and are never registered with any hosting company by the malware author. They will however, create noise in network logs and annoy Analysts attempting to find active C&C domains.
Although these requests to the NXdomains do not resolve, at OpenDNS, we still see the attempted request in our DNS query logs. Recently, I have found that analyzing these sessions of DGA requests in our logs has proven effective at surfacing other types of malicious domains that are queried in the event.

Why so effective?

While malware authors have found DGAs to be an effective way of hiding C&C traffic, what I’ll be talking about is how they’re effective in surfacing other related malicious infrastructure. This surfaces domains that become guilty by hanging out with the wrong crowd. If I can see that there is already some shady DGA business going on, and said domain does not match the known DGA pattern, but appears in the session, it’s worth examining. After singling out a session of DNS requests with many consecutive sudden requests to NXdomains, you will also find some resolving DGA domains. They typically only resolve for a short period of time. Amongst these resolving domains is where it becomes interesting, and becomes an effective place for hunting. Examining these domains will also give you further insight into how specific malware functions.
In an identified session of Necurs DGA callouts, we can identify the first DGA round beginning with a callout to top level ‘com’ domains that are unpredictable, and used by the malware to detect simulated network traffic in order to evade analysis. [1] The 2nd and 3rd round of DGA callouts will then begin if not thought to be running in a lab environment. We find the majority of the 2nd and 3rd round DGAs to be sinkholed.
uqhucsontf[.]com
myypqmvzkgnrf[.]com
ocufxskoiegqvv[.]com
uflhdvsnjmfgcp[.]so
otopshphtnhml[.]net
aiygrmsryphqlkfcld[.]su
etfxkiqtriteysf[.]pw
crigtwrdtxbcmsgjkmx[.]tv
cjyioboxmxhsmrclrhxxl[.]im
soqikjyliunjqaciqlg[.]tj
jrguloma[.]biz
anlxccqeqflidpwyhobm[.]ir

Surfacing malicious infrastructure

On Oct 3rd, an interesting domain stood out amongst this DGA session; xic[.]graphics.

oumulcchlccvhsb[.]la
wolnltrixnidaaqaqty[.]tw
awwxmmbhkpedjnycrh[.]eu
kaxtnqdkxigrg[.]cx
gwhhpnrfkdiedhga[.]ki
sxurcsgyrnob[.]tw
pmir.3g.qq1[.]com
xic[.]graphics
Around this date, messages were received by users on Facebook containing a link to xic[.]graphics. Reportedly, this site was installing a malicious browser extension once a user clicked an image to view a “video” contained in the message.  [2],[3]
After looking at the email registrant of xic[.]graphics, we found that this account had registered numerous other domains that were being used in the same type of campaigns: lololokokokovovovo[.]com, futunga[.]com, todayonlynews[.]com, utopgames[.]com .
lololokokokovovovo[.]com had a similar spike in traffic during this period as xic[.]graphics and shared the same html source code while it was live.

graphics-traffic
lolo-traffic

We are currently blocking all domains registered by this email registrant; mhungetuoy@gmail[.]com.

registrant

The IP address, 51.254.198[.]136 that some of these domains resolve to reveals more infrastructure belonging to the attackers. The domains seem to be involved in similar attacks and were all full of jumbled words, with Facebook image links in the source.
As of this posting, some of the domains seem to be moving IPs and are now resolving to 178.32.125[.]10. The nameservers of ns1.futunga[.]com, ns2.futunga[.]com are still in use.
Resolving to 178.32.125[.]10, utopgames[.]com is still hosting the same type of images used in the Facebook message campaigns of xic[.]graphics. It also has similar source code.

utopgames
image from utopgames[.]com
facebookimage
image from utopgames[.]com

We found some “testing” being done with JS files on various ‘pw’ TLD domains hosted on these IP addresses. The samples simply contained the word “TEST”. However, coming from this infrastructure, it is suspicious.

urls
URLs linking to JS files on PW domain
pw
Traffic spike on PW domain

When sampling a portion of our DGA sessions to see which TLD’s are seen most often, the TLD ‘pw’ ranked at 0.961 (1 being the highest possible ranking.) The following ‘pw’ domains were seen resolving to the IP addresses mentioned and host similar URLs to JS files.
budaner[.]pw
facimago[.]pw
fokelyio[.]pw
kalaner[.]pw
kamirop[.]pw
lakonaci[.]pw
lokelys[.]pw
momeros[.]pw
sokciso[.]pw
sonbkos[.]pw
sonmerahpaga[.]pw
tekcise[.]pw
tokciko[.]pw
vslaner[.]pw

Previous Post:

Previous Article

Next Post:

Next Article

Follow Us

  • Twitter
  • Facebook
  • LinkedIn
  • YouTube

Footer Sections

What we make

  • Cloud Security Service
  • DNS-Layer Network Security
  • Secure Web Gateway
  • Security Packages

Who we are

  • Global Cloud Architecture
  • Cloud Network Status
  • Cloud Network Activity
  • OpenDNS is now Umbrella
  • Cisco Umbrella Blog

Learn more

  • Webinars
  • Careers
  • Support
  • Cisco Umbrella Live Demo
  • Contact Sales
Umbrella by Cisco
208.67.222.222+208.67.220.220
2620:119:35::35+2620:119:53::53
Sign up for a Free Trial
  • Cisco Online Privacy Statement
  • Terms of Service
  • Sitemap

© 2022 Cisco Umbrella