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© ETH Zürich | ICT-Networks/NSG [email protected] 27.08.2015 Simple Anomaly Detection via Netflows

ETH_Anomaly-Detection-in-Netflows-PPT_v2_of_year_2013

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Page 1: ETH_Anomaly-Detection-in-Netflows-PPT_v2_of_year_2013

© ETH Zürich | ICT-Networks/NSG [email protected] 27.08.2015

Simple Anomaly Detection via Netflows

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The Big Question:What Is Under The Radar?

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First Goal (1)

To create an automated method of detectingunusual connections and/or anomalies with netflows, thereby finding compromised hosts

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Top Down Method Works Well With IDS

4

N=100

P2P BitTorrent transfer „Deviation“ (total traffic)

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Netflow Anomaly DetectionTop Down Strategy

Analyzing the total traffic down to individual hostsby detecting behavioral deviations.

Been there and done that with netflows (2008).

The problem:Even though a malicious traffic event is usuallyan anomaly, an anomaly is not always a malicious event

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With an automated method, finding the correlating netflows of incidents regardless of source of information (IDS, Switch, AV, User, Admin, Netflows)

New Goal (2)

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Netflow Anomaly Detection Bottom up Strategy

Viewing what an individual host is doing compared to the general population

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Common Problems Regardless of Source of Information

• Vague Indications• Detected Anomalies• Recurring Compromise• False Negatives• False Positives

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google

facebook

youtube

InternetETH

Usual Connections

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google

facebook

youtube

???????

InternetETH

Unusual Connections

???????Causing IDS anomalies

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google

facebook

youtube

???????

InternetETH

Correlations/Validations

???????Causing IDS anomalies

???????

??????? 11

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Pros and Cons With This MethodPro: It is automatic and indeed sometimes successfullCon: It may take a long time to run

Again:All anomalies are not malicious.

The potential problem is when the individual host is generating harmless but very diverse unusal traffic.

Both pros and cons:It is possible to automatically sort the connections based on how usual/unusal they are

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google

facebook

youtube

?

InternetETH

Unusal Connections

?

Causing IDS anomalies ?

?

?

?

?

?

?

?

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A Real Example (Switch)[SWITCH-CERT #22814x ]Most likely compromised system[129.132.208.10x][Botnet]

Based on received information about a ‘malicious IRC command master at 183.203.15.205

2013-08-14 17:40:08.07014

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./analyzerdynamic2.sh 129.132.208.10x 20130814 1800 Enter Comment. End it with ^DSubject: [SWITCH-CERT #228144] Most likely compromised system [129.132.208.10x ...] [Botnet]Done. Comment stored in -rw-r--r-- 1 hall nsg 93 Aug 22 18:05 commentDEBUG: starthour:201308141700 endhour:201308141800 startday:201308131800port:-1First DYNAMIC STAGE *************************************nfdump -M /nfsen -R nfcapd.201308141700:nfcapd.201308141800 '( host129.132.208.10x )' | grep ^2013 | awk '{ print $7 }' | sed s/:/\ /g | awk '{ print $1 }' | grep -v "129.132.208.10x:"\ | sort -u > ./analyzer_129.132.208.10x.outp Debug dnumber:41 Second DYNAMIC STAGE *************************************107.21.234.205112 107.21.234.205 (40)108.160.162.531938 108.160.162.53 (39)108.160.163.46229 108.160.163.46 (38)12.130.131.80120 12.130.131.80 (37)... 15

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…120 121 12.130.131.80 10 5.0000000 .8264462112 113 107.21.234.205 11 4.5454545 .884955795 96 77.67.22.188 2 .7142857 1.041666645 46 62.146.92.202 12 1.090909 2.1739130434 35 137.205.124.72 3 .2497918 2.857142829 30 54.224.40.139 10 4.8309178 3.333333327 28 134.60.1.5 13 .0336482 3.571428523 24 88.156.222.90 4 1.8691588 4.166666617 18 178.63.20.18 5 2.6041666 5.55555557 8 193.36.36.16 91 5.6627255 12.50000003 3 183.203.8.238 1 .0959692 33.33333332 3 183.203.15.205 34 3.333333 33.3333333

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List ResultN

umbe

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ps

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vest

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100

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Blacklist Check Routine77.67.22.18862.146.92.202137.205.124.7254.224.40.139134.60.1.588.156.222.90178.63.20.18193.36.36.16183.203.8.238183.203.15.205botcc:183.203.15.205

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183.203.8.238

InternetETH

Further Correlations/Validations

Can Now be Done

183.203.15.205

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129.132.208.10x

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The Concept in a Nutshell

1. Find all connections around the investigatedIP over a 60 minute period

2. Take those connections and rate how usual (or unusal) these are in the general population over a 24hr period

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Find All Connections Around the InvestigatedIP Over a 60 Minute Period

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Time point of interestfor the investigated ip

InternetInvestigated IP at ETH network

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Take Those Connections and Rate How Usual (or Unusal) These are in the General

Population Over a 24hr Period

InternetETH network

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Another Real Example (IDS)

IDS Event with destination google:

EVENT: ET TROJAN Zeus Bot Get to Google checking Internet connectivity Date: 08/24-13:13:01.713666 SOURCE: 129.132.211.21x:50086 DEST: 173.194.112.210.80

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./analyzerdynamic2.sh 129.132.211.21x 20130824 1320 Enter Comment. End it with ^DEVENT: ET TROJAN Zeus Bot Get to Google checking Internet connectivity DATE: 08/24-13:13:01.713666 SOURCE: 129.132.211.21x:50086 DEST: 173.194.112.210:80 Done. Comment stored in -rw-r--r-- 1 hall nsg 124 Aug 28 15:41 commentDEBUG: starthour:201308241220 endhour:201308241320 startday:201308231320port:-1First DYNAMIC STAGE *************************************nfdump -M /nfsen -R nfcapd.201308241220:nfcapd.201308241320 '( host129.132.211.215 )' | grep ^2013 | awk '{ print $7 }' | sed s/:/\ /g | awk '{ print $1 }' | grep -v "129.132.211.21x:"\ | sort -u > ./analyzer_129.132.211.21x.outp Debug dnumber:90 Second DYNAMIC STAGE *************************************108.160.162.111133 108.160.162.111 (89)108.160.162.99118 108.160.162.99 (88)111.111.111.11119 111.111.111.111 (87)12.161.242.20...

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List Result

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…19 20 66.70.34.97 3 4.531722054 5.000000000019 19 111.111.111.111 148 .267413497 5.263157894714 15 77.72.169.160 24 4.633204633 6.666666666614 15 62.146.42.159 15 15.463917525 6.666666666614 15 98.139.205.30 9 20.930232558 6.66666666669 10 50.17.207.124 3 23.076923076 10.00000000006 7 98.139.114.30 6 31.578947368 14.28571428575 6 204.13.161.111 154 15.247524752 16.66666666665 6 54.225.249.200 14 28.000000000 16.66666666662 3 77.72.174.136 15 93.750000000 33.33333333331 2 140.116.72.75 2 100.000000000 50.00000000001 2 173.194.112.210 4 100.000000000 50.00000000001 2 66.196.120.57 2 100.000000000 50.00000000001 2 66.196.121.20 24 100.000000000 50.0000000000

Num

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0

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Blacklist Check Routine…66.70.34.97111.111.111.11177.72.169.16062.146.42.15998.139.205.3050.17.207.124pbl:!50.17.207.12498.139.114.30204.13.161.11154.225.249.20077.72.174.136140.116.72.75sbl hit: 140.116.72.75173.194.112.21066.196.120.5766.196.121.20    25

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Black List SBL Referencehttp://www.spamhaus.org/sbl/query/SBL193024 Ref: SBL193024140.116.72.75/32 is listed on the Spamhaus Block List - SBL140.116.72.75/32 is listed on the Spamhaus Botnet C&C List - BGPCC2013-08-26 15:56:50 GMT | edu.twCitadel botnet controller @140.116.72.75 Update Aug 26, 2013 Problem still exists, Citadel botnet controller located here:http://dashuxmaecrme.com/wel/file.phphttp://dashuxmaecrme.com/wel/qwrt.phphttp://frontrunnings.com/fdet/file.phphttp://joyrideengend.net/wel/file.phphttp://spottingculde.com/wel/file.phphttp://eenyellowredpf.su/wel/file.phphttp://stabilitymess.net/wel/file.phphttp://systemlevelge.com/wel/file.php…    

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Possible to do’s

• Include (dest) Port in the analysis• Automatically track compromised Ips• Automatically analyse compromised Ips• Automatically build and update CC lists• Automatically correlation check between CC-

clusters and malware

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Q&A

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END

29Christian Hallqvist / Network Security / [email protected]