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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi List,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">I recently noticed, that a couple of signatures trigger quite often, but the eve log does not show the details (source/destination) it usually does.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">{<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "timestamp": "2016-07-04T14:07:36.256364+0200",<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "alert": {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "action": "allowed",<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "gid": 1,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "signature_id": 2404022,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "rev": 4278,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "signature": "ET CNC Shadowserver Reported CnC Server IP group 23",<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "category": "A Network Trojan was detected",<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> "severity": 1<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">}<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">The fast log shows some detail about the raw packet<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">07/04/2016-14:07:36.256364 [**] [1:2404022:4278] ET CNC Shadowserver Reported CnC Server IP group 23 [**] [Classification: A Network Trojan was detected] [Priority:
1] [**] [Raw pkt: 01 80 C2 00 00 00 00 1C 58 BE 88 90 00 27 42 42 03 00 00 02 02 3C 8F 10 00 1B 2B 09 7C 00 00 00 ]<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Google shows that others have had similar Problems in the past:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">https://lists.openinfosecfoundation.org/pipermail/oisf-users/2014-March/003570.html<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">I captured some traffic (I can upload/send the pcap to someone/somewhere if needed) and Wireshark says it is a Spanning Tree Protocol Packet in a 802.3 Ethernet
Frame. I do not understand why the ET Signature is triggering:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">alert ip $HOME_NET any -> [213.114.67.147,213.165.242.16,213.168.249.130,213.17.153.11,213.193.246.34,213.200.94.170,213.230.192.163,213.239.193.176,213.249.68.98,216.152.78.166,216.18.189.186]
any (msg:"ET CNC Shadowserver Reported CnC Server IP group 23"; reference:url,doc.emergingthreats.net/bin/view/Main/BotCC; reference:url,www.shadowserver.org; threshold: type limit, track by_src, seconds 3600, count 1; flowbits:set,ET.Evil; flowbits:set,ET.BotccIP;
classtype:trojan-activity; sid:2404022; rev:4278;)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Is this a configuration issue? Or is suricata misinterpreting the packet?
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">We’re using suricata 3.1<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Regards
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif"">Chris<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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