The DFIR Report<p>“In this specific case, thanks to the capabilities of Sysmon, and particularly Event ID 22, we can easily gain insight into the subdomains that were used. For this case we observed TXT records being utilized for C2 communication rather than MX records. This can be identified by the "type: 16" in the Sysmon logs seen above. </p><p>Below is a sample list that, while not exhaustive, provides a clear example of the traffic patterns:”</p><p>The above is from a recent Private Threat Brief: "A MadMXShell Encore"</p><p> Services: <a href="https://thedfirreport.com/services/" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://</span><span class="">thedfirreport.com/services/</span><span class="invisible"></span></a></p><p> Contact Us: <a href="https://thedfirreport.com/contact/" rel="nofollow noopener noreferrer" translate="no" target="_blank"><span class="invisible">https://</span><span class="">thedfirreport.com/contact/</span><span class="invisible"></span></a></p><p><a href="https://infosec.exchange/tags/dfir" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>dfir</span></a> <a href="https://infosec.exchange/tags/IncidentResponse" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>IncidentResponse</span></a> <a href="https://infosec.exchange/tags/BlueTeam" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>BlueTeam</span></a> <a href="https://infosec.exchange/tags/cti" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>cti</span></a> <a href="https://infosec.exchange/tags/ThreatIntel" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>ThreatIntel</span></a> <a href="https://infosec.exchange/tags/threatintelligence" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>threatintelligence</span></a></p>