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<div class="WordSection1">
<p class="MsoNormal">Hey all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> CIRA is seeing a spike in 13-character pseudo-random queries for two of the ~40 TLD’s we host on our anycast platform.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="margin-left:54.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">1)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>The goal likely isn’t of a DDoS nature as the volumes are too small and steady.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> We’re talking < 15,000 qps total across two clouds with nodes in a dozen+ sites.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="margin-left:54.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">2)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>This has been going on for at least two weeks.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> This didn’t hit the threshold for alerting, so it largely went unnoticed until our Hadoop team doing analytics and monthly reports pointed it out.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="margin-left:54.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">3)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>The traffic appears to be mostly sourced from Europe.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Our sites in Europe in each of our clouds are taking about 90% of these DNS queries.<o:p></o:p></p>
<p class="MsoNormal"> A check of the IP’s hitting our servers in Europe show European ownership for all of the heavy-hitters.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="margin-left:54.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">4)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>The queries do not appear to be spoofed.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> We see the same “random” query string from 2 or 3 IP’s in the same subnet in quick succession, from which we see non-pseudorandom queries, which would indicate standard use of a legit set of recursive DNS
servers. Vast majority are not open resolvers.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="margin-left:54.0pt;text-indent:-18.0pt;mso-list:l0 level1 lfo2">
<![if !supportLists]><span style="mso-list:Ignore">5)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>The same “random” string appears occasionally in the query sets for each of the TLD’s in question.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Example: ff5ae6d7e1981.<TLD>, 788c439b7adf3.<TLD><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> This very much feels like your standard malware using DNS domain generation algorithms for C&C. Am I missing anything, or is my deduction likely correct?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> Anyone else seeing activity like this sourced almost exclusively from Europe in it’s geographic distribution?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> I’m guessing it’s not worth contacting the recursive server operators at this non-impacting volume, but I’d like to rule out any other motivations besides malware C&C.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-Jacob Zack<o:p></o:p></p>
<p class="MsoNormal">DNS Architect – CIRA (.CA TLD)<o:p></o:p></p>
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