SCANdalous! (External Detection Using Network Scan Data and Automation)[html]
Real Quick
In case you’re thrown by that fantastic title, our lawyers made us
change the name of this project so we wouldn’t get sued.
SCANdalous—a.k.a. Scannah Montana a.k.a. Scanny McScanface a.k.a.
“Scan I Kick It? (Yes You Scan)”—had another name before today that,
for legal reasons, we’re keeping to ourselves. A special thanks to our
legal team who is always looking out for us, this blog post would be a
lot less fun without them. Strap in folks.
Introduction
Advanced Practices is known for using primary source data obtained
through href="/content/fireeye-www/en_US/services/mandiant-incident-response.html">Mandiant
Incident Response, href="/content/fireeye-www/en_US/solutions/managed-defense.html">Managed
Defense, and product telemetry across thousands of FireEye
clients. Regular, first-hand observations of threat actors afford us
opportunities to learn intimate details of their modus operandi. While
our visibility from organic data is vast, we also derive value from
third-party data sources. By looking outwards, we extend our
visibility beyond our clients’ environments and shorten the time it
takes to detect adversaries in the wild—often before they initiate
intrusions against our clients.
In October 2019, Aaron Stephens gave his href="https://www.youtube.com/watch?v=x1tEOkY-7JE">“Scan’t Touch
This” talk at the annual FireEye Cyber Defense Summit (slides
available href="https://github.com/aaronst/talks/blob/master/scanttouchthis.pdf">on
his Github). He discussed using network scan data for external
detection and provided examples of how to profile command and control
(C2) servers for various post-exploitation frameworks used by criminal
and intelligence organizations alike. However, manual application of
those techniques doesn’t scale. It may work if your role focuses on
one or two groups, but Advanced Practices’ scope is much broader. We
needed a solution that would enable us to track thousands of groups,
malware families and profiles. In this blog post we’d like to talk
about that journey, highlight some wins, and for the first time
publicly, introduce the project behind it all: SCANdalous.
Pre-SCANdalous Case Studies
Prior to any sort of system or automation, our team used traditional
profiling methodologies to manually identify servers of interest. The
following are some examples. The success we found in these case
studies served as the primary motivation for SCANdalous.
APT39 SSH Tunneling
After observing APT39 in a series of intrusions, we determined they
frequently created href="/content/fireeye-www/en_US/blog/threat-research/2019/01/bypassing-network-restrictions-through-rdp-tunneling.html">Secure
Shell (SSH) tunnels with PuTTY Link to forward Remote Desktop
Protocol connections to internal hosts within the target
environment. Additionally, they preferred using BitVise SSH servers
listening on port 443. Finally, they were using servers hosted by
WorldStream B.V.
Independent isolation of any one of these characteristics would
produce a lot of unrelated servers; however, the aggregation of
characteristics provided a strong signal for newly established
infrastructure of interest. We used this established profile and
others to illuminate dozens of servers we later attributed to href="/content/fireeye-www/en_US/blog/threat-research/2019/01/apt39-iranian-cyber-espionage-group-focused-on-personal-information.html">APT39,
often before they were used against a target.
APT34 QUADAGENT
In February 2018, an independent researcher shared a sample of what
would later be named QUADAGENT. We had not observed it in an intrusion
yet; however, by analyzing the characteristics of the C2, we were able
to develop a strong profile of the servers to track over time. For
example, our team identified the server class="code">185.161.208\.37 and domain class="code">rdppath\.com within hours of it being established.
A week later, we identified a QUADAGENT dropper with the previously
identified C2. Additional examples of QUADAGENT are depicted in Figure 1.
src="https://www.fireeye.com/content/dam/fireeye-www/blog/images/scandalous/Picture1.png" alt="" />
Figure 1: QUADAGENT C2 servers in the
Shodan user interface
Five days after the QUADAGENT dropper was identified, Mandiant was
engaged by a victim that was targeted via the same C2. This activity
was later attributed to APT34. During the investigation, Mandiant
uncovered APT34 using RULER.HOMEPAGE. This was the first time our
consultants observed the tool and technique used in the wild by a real
threat actor. Our team developed a profile of servers hosting HOMEPAGE
payloads and began tracking their deployment in the wild. Figure 2
shows a timeline of QUADAGENT C2 servers discovered between February
and November of 2018.
src="https://www.fireeye.com/content/dam/fireeye-www/blog/images/scandalous/Picture2a.jpg" alt="" />
Figure 2: Timeline of QUADAGENT C2 servers discovered
throughout 2018
APT33 RULER.HOMEPAGE, POSHC2, and POWERTON
A month after that aforementioned intrusion, Managed Defense
discovered a threat actor using RULER.HOMEPAGE to download and execute
POSHC2. All the RULER.HOMEPAGE servers were previously identified due
to our efforts. Our team developed a profile for POSHC2 and began
tracking their deployment in the wild. The threat actor pivoted to a
novel PowerShell backdoor, POWERTON. Our team repeated our workflow
and began illuminating those C2 servers as well. This activity was
later attributed to APT33 and was documented in our
