Detecting network attacks with mathematical methods and OCR algorithms With novel case studies :)

Detecting network attacks with mathematical methods and OCR

algorithmsWith novel case studies :)

Chetvertakov VitaliyYarochkin FedorKropotov Vladimir

Pattern Recognition

Pattern Recognition is the assignment of a label to a given input value. Pattern recognition algorithms generally aim to provide a

reasonable answer for all possible inputs and to perform "most likely" matching of the inputs, taking into account their statistical variation.

(source: wikipedia)

Recognizing patterns in HTTP traffic

Feature selection: identify features of HTTP request that uniquely describe the “object”

Pick a classification algorithm Refine the classification process by updating

and extending the feature set

Feature Selection

Use abstract features. Identify optimal feature set Identify features which are specific to a

particular class

http://tmffh9d6.inspectionimagination.biz:34412/8b3fb0644ab7b15a8e4934b02ac816de.html

http://tmffh9d6.inspectionimagination.biz:34412/2442801631/1383804540.tpl

http://tmffh9d6.inspectionimagination.biz:34412/2442801631/1383804540.jar

Feature selection

Feature selection

r3k29.custardpeach.biz:51423/915511fb10676aa529fc4228b67066df.html

Domain

- length of the domain name- TLD/domain level- use of non-standard port- use of constant strings in DGA- parts of domain/subdomain are fixed

URL

- length of theURL- depth- number of parameters- use of constants in URL generation

Training classifier

Case method — use of real-life objects and known classes to train classifier

Example 01GET;http://l03dn5.presidentsdaypretty.biz:39031/04e0f64971f8e578f67c06fdca6eaa19/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://pzsch506.groundhogdayglamour.biz:39031/b2f7b3d0871f2c12e234af9b256544cc/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://yvuia4.purimpearl.biz:39031/2a3550cbd3647dc0ce8d1f9fba0834bf/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://zw3mj5wj.purimpearl.biz:39031/a1ba1f03f1b2aa47616cfb3444e7cffd/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://hza8wu.fathersdaydelight.biz:39031/ca59b25fe5eb041b0981ba47437f6165/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://kutro.kwanzaavanity.biz:39031/d4ec6dcbc4ef5bf2a6baf84b341cea8f.html;HTTP/1.1

GET;http://mvgui.chinesenewyeartrendy.biz:39031/2f8a9fba52135e1dde57aba3073f18be/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://edbl5bx.newyearsevegrace.biz:39031/0d33e5b8022599e83176ed9c43b2c955/1/5f59cefce9266019c504ca4a71621b1c.html;HTTP/1.1

GET;http://u68mbrep.purimpearl.biz:39031/559d030ea579f78dd8e81e394fb084e3.html;HTTP/1.1

GET;http://ouytbyb.kwanzaavanity.biz:39031/1a66d53d7d940ac8d1a5fb6302f9eb2d.html;HTTP/1.1

GET;http://wiizc.purimpearl.biz:39031/6bfa9cf7fc9b6d0f16728765a19f7ee8.html;HTTP/1.1

GET;http://a0e9nd.kwanzaavanity.biz:39031/110e3640c62e5e4cfdc1821c6cd57447.html;HTTP/1.1

GET;http://xfapcjn.purimpearl.biz:39031/665025fd70aedc98dea3939f576f2466.html;HTTP/1.1

GET;http://qr47s.kwanzaavanity.biz:39031/772cd514992254f1c052988cdaaa36e9.html;HTTP/1.1

kutro.kwanzaavanity.biz:39031/d4ec6dcbc4ef5bf2a6baf84b341cea8f.html

<method>GET</method><domain><domainlevels>3</domainlevels><domainlengthmin>20</domainlengthmin><domainlengthmax>32</domainlengthmax><domainconstants>biz</domainconstants></domain><URL><urlmin>37</urlmin><urlmax>72</urlmax><numberofdirs>3#1</numberofdirs><urlconstants>html</urlconstants><hashinurl>True</hashinurl></URL><Ports>39031</Ports><Useragent></Useragent>/* Only for POST method */ <ref>True</ref>

Example 02

GET;http://wrauac.dns-dns.com/profile.php?exp=atom&b=029c737&k=1d7b5b52cde770adae2f2de599b2c6aa;HTTP/1.1

GET;http://wrauac.dns-dns.com/profile.php?exp=atom&b=029c737&k=1d7b5b52cde770adae2f2de599b2c6aa;HTTP/1.1

GET;http://wrauac.dns-dns.com/profile.php?exp=byte&b=029c737&k=1d7b5b52cde770adae2f2de599b2c6aa;HTTP/1.1

GET;http://viwocasl.sendsmtp.com/profile.php?exp=byte&b=029c737&k=6edca1a2b6fd09b6d34b09c89338b7b1;HTTP/1.1

GET;http://viwocasl.sendsmtp.com/profile.php?exp=atom&b=029c737&k=6edca1a2b6fd09b6d34b09c89338b7b1;HTTP/1.1

GET;http://chopupruu.esmtp.biz/profile.php?exp=atom&b=2266390&k=a851e76a784b954dac7616e2e825cdb8;HTTP/1.1

GET;http://chopupruu.esmtp.biz/profile.php?exp=byte&b=2266390&k=a851e76a784b954dac7616e2e825cdb8;HTTP/1.1

GET;http://gukasoui.dns04.com/profile.php?exp=byte&b=029c737&k=e4697d1bc39e76560b8c17333efb252c;HTTP/1.1

GET;http://gukasoui.dns04.com/profile.php?exp=atom&b=029c737&k=e4697d1bc39e76560b8c17333efb252c;HTTP/1.1

GET;http://trajespaw.sellclassics.com/profile.php?exp=byte&b=029c737&k=df5583b1ef47cafe68949194862ae422;HTTP/1.1

GET;http://trajespaw.sellclassics.com/profile.php?exp=atom&b=029c737&k=df5583b1ef47cafe68949194862ae422;HTTP/1.1

GET;http://trajespaw.sellclassics.com/profile.php?exp=atom%26b=029c737%26k=f19c80074df797aa3a59aaeabc8a78fd;HTTP/1.1

GET;http://trajespaw.sellclassics.com/profile.php?exp=byte%26b=029c737%26k=f19c80074df797aa3a59aaeabc8a78fd;HTTP/1.1

http://wrauac.dns-dns.com/profile.php?exp=atom&b=029c737&k=1d7b5b52cde770adae2f2de599b2c6aa

<method>GET</method><domain><domainlevels>3</domainlevels><domainlengthmin>18</domainlengthmin><domainlengthmax>26</domainlengthmax><domainconstants></domainconstants></domain><URL><urlmin>65</urlmin><urlmax>69</urlmax><numberofdirs>1</numberofdirs><urlconstants>profile#php#exp</urlconstants><hashinurl>True</hashinurl></URL><Ports></Ports><Useragent></Useragent>/* Only for POST method */ <ref>False</ref>

Example 03GET;http://122007dd1019.kathell.com/get2.php?

c=HNCHAIMZ&d=26606B67393435363E2F676268307D3F222022222525253177757E4469747A22461516161D1444440E5C434F116E1E6B76000A7006760E06090D0A080D7F0A0674707B00007007057F087C7A756B2C263E273721696461647E31333F61683B6C520557505643070305545A4D031E180A024C472C455329031B12474A4D494C4EB8B2B0BBB5A3F6F5E7EAB7CEF4FDE2E0E2F4E0BDD1CDD3B1F4FDABC4F9A0AFB9C3CDCCD7FBC09B978EDE9C9F919D88C98D818095D0D0DAD6C1848A8B8C8D8E8FF0F0E4A0AAA1AAFA859A81FAF5F8FBE1BDA2B9FDA6BBF8A5ADFFB3BFBDA9BBE2D1D3DADBDCD7D4D6D8D9CCAEA3BF

GET;http://162007dd1009.kathell.com/get2.php?c=AFVJIJKP&d=26606B67393435363E2F676268307D3F222022222525253177757E4469747A2218191A17124343160E5C434F1168181C03017101000474750A0D7E0C097F7D7D027906027D7307700C7972720E6B2C263E273721696461647E31333F616B6C39515204015043070305545A4D031E180A024C442C455329031B12474B484A4B46B2B1B2B3B7A3F6F5E7EAB7F9F9E3EAE3FCA2A0BDF1EDF3B1F4FDABC4F9A0AFB9C3CDCCD7FBC09B978EDE9C9F919C88C98D8094C1898490D4D6DDD686F8FFF08DF5F5F4EDA9B6ADE9BAA7E4B9B9EBA7ABB1A5B7EEE5E7EEEFE0EBE8EAECEDF89AAFB3

GET;http://162007dd100a.kathell.com/get2.php?c=AFVJIJKP&d=26606B67393435363E2F676268307D3F222022222525253177757E4469747A2218191A17124343160E5C434F1168181C03017101000474750A0D7E0C097F7D7D027906027D7307700C7972720E6B2C263E273721696461647E31333F616B6C39515204015043070305545A4D031E180A024C442C455329031B12474B484A4B46B8B3B0BAB0A3F6F5E7EAB7F9F9E3EAE3FCA2A0BDF1EDF3B1F4FDABC4F9A0AFB9C3CDCCD7FBC09B978EDE9C9F919C88C98D818095D0D0DAD6C1848A8B8C8D8E8FF0F0E4A0AAA1AAFA8C8B84F9F9F9F8E1BDA2B9FDA6BBF8A5ADFFB3BFBDA9BBE2D1D3DADBDCD7D4D6D8D9CCAEA3BF

GET;http://201907dd1008.kathell.com/get2.php?c=HNCHAIMZ&d=26606B67393435363E2F676268307D3F222022222525253177757E4469747A22461516161D1444440E5C434F116E1E6B76000A7006760E06090D0A080D7F0A0674707B00007007057F087C7A756B2C263E273721696461647E31333F61683B6C520557505643070305545A4D031E180A024C472C455329031B12474A4C454D4AB6B1BAB1BCA3F6F5E7EAB7CEF4FDE2E0E2F4E0BDD1CDD3B1F4FDABC4F9A0AFB9C3CDCCD7FBC09B978EDE9C9F919D88C98D8094C1898490D4D6DDD686F1EEF58EF9F4F7EDA9B6ADE9BAA7E4B9B9EBA7ABB1A5B7EEE5E7EEEFE0EBE8EAECEDF89AAFB3

GET;http://201907dd1009.kathell.com/get2.php?c=HNCHAIMZ&d=26606B67393435363E2F676268307D3F222022222525253177757E4469747A22461516161D1444440E5C434F116E1E6B76000A7006760E06090D0A080D7F0A0674707B00007007057F087C7A756B2C263E273721696461647E31333F61683B6C520557505643070305545A4D031E180A024C472C455329031B12474A4C454D49B2B2B2B4BCA3F6F5E7EAB7CEF4FDE2E0E2F4E0BDD1CDD3B1F4FDABC4F9A0AFB9C3CDCCD7FBC09B978EDE9C9F919D88C98D818095D0D0DAD6C1848A8B8C8D8E8FF0F0E4A0AAA1AAFA859A81FAF5F8FBE1BDA2B9FDA6BBF8A5ADFFB3BFBDA9BBE2D1D3DADBDCD7D4D6D8D9CCAEA3BF

<method>GET</method><domain><domainlevels>3</domainlevels><domainlengthmin>24</domainlengthmin><domainlengthmax>24</domainlengthmax><domainconstants>kathell#com</domainconstants></domain><URL><urlmin>438</urlmin><urlmax>498</urlmax><numberofdirs>1</numberofdirs><urlconstants>get2#php</urlconstants><hashinurl>False</hashinurl></URL><Ports></Ports><Useragent></Useragent>/* Only for POST method */ <ref>False</ref>

Classification methods

Expert Systems Supervised Learning & Unsupervised Learning Probabilistic Classifiers Bayes Classifiers Neural Network Classifier Markov-chainand so on

Expert System

Expert System - is a computer system that emulates the decision-making ability of a human expert (Thank you, Wikipedia ;-))

Neural Networks

Artificial Neural Networks (ANF) - artificial neural networks are computational models inspired by animal central nervous systems (in particular the brain) that are capable of machine learning and pattern recognition. They are usually presented as systems of interconnected "neurons" that can compute values from inputs by feeding information through the network. (wikipedia ;))

First try

Method Input data Need to recognize

Total matches Found False positives

Comparision based expert system

>15000000 lines

361 lines 667 lines 335 lines 332 lines

Weight-based expert system

>15000000 lines


Neural Network >15000000 lines


Correction

Add new features, or modify existing Correct the decision system logic Add whitelists Extend the training set

After correction

Method Input data Need to recognize

Total matches Found False positives

Comparision based expert system

>15000000 lines


Weight-based expert system

>15000000 lines


Neural Network

>15000000 lines


Comparison based

Weight-based method

Neural network

eonudr.newyearsevemagical.biz 142.4.194.2

iewc7.valentinesdaypearl.biz 142.4.194.2

m32fa1o.electiondaypretty.biz 142.4.194.2

mcojt0a.purimcharming.biz 142.4.194.2

rum49.newyearsevemagical.biz 142.4.194.2

hword.meok.info 67.211.199.230

katadod.pp.ua 82.146.58.179

tatytol.pp.ua 82.146.58.179

142.4.194.2

67.211.199.230

82.146.58.179

Выгрузка по обнаруженным IP

Метод Обнаружено различных IP

Количество строк при поиске по IP

Необходимо распознать

Экспертная система на основе сравнений

3 IP 361 строку 361 строку

Экспертная система на основе весов

3 IP 361 строку 361 строку

Нейронная сеть 3 IP 361 строку 361 строку

GET;http://img.downloadcontent.info/jquery.phtml?jsoncallback=jQuery1101008466942954555645_1383617770561&_=1383617770562;HTTP/1.1 67.211.199.230



GET;http://hellobodydown.info/iRDgI.gif?44662;HTTP/1.1 67.211.199.230

GET;http://hword.meok.info/viewtopic.php?p=23438&sid=8dba5ca35;HTTP/1.1 67.211.199.230

GET;http://hword.meok.info/engine/classes/js/jquery.js;HTTP/1.1 67.211.199.230

GET;http://hword.meok.info/counter.php;HTTP/1.1 67.211.199.230


GET;http://hellobodydown.info/BLPXdu5e.gif?179612;HTTP/1.1 67.211.199.230

GET;http://hword.meok.info/viewtopic.php?p=99505&sid=a83f64f;HTTP/1.1 67.211.199.230




GET;http://hellobodydown.info/KeyAKRx.gif?1755;HTTP/1.1 67.211.199.230

GET;http://hword.meok.info/viewtopic.php?p=58087&sid=bf5532a8118;HTTP/1.1 67.211.199.230



Kolmogorov complexity

In algorithmic information theory (a subfield of computer science and mathematics), the Kolmogorov complexity (also known as descriptive complexity, Kolmogorov–Chaitin complexity, algorithmic entropy, or program-size complexity) of an object, such as a piece of text, is a measure of the computational resources needed to specify the object.

Brainfuck

One of esoteric programming languages invented by Urban Muller in 1993.

Example

'http://uhvfsd.servebbs.net/haperka.php'

>++++++++++++++++[>++++++>+++++++>+++>++<<<<-]>>--------.++++++++++++..----.>+++

+++++++.-----------..<+++++.<++++++++.>+.<--.>---.<--.>>-.<.<+.>-.++++.<.---..>---.>.<-----.<+++.>++++++.>+.<<+++.-------.>----.<++++.>++.<++++++.----------.>>-.<--.<+++++++.>.>>[[-]<]<

http://uhvfsd.servebbs.net/haperka.php

Example 2

http://adylody.pp.ua/hit-partner-stat/f8850826775010c65885e32c1a7f29ff?x=160

>++++++++++++++++[>++++++>+++++++>+++>++<<<<-]>>--------.++++++++++++..----.>++++++++++.-----------..<<+.+++.>+++++++++.<++++++++.+++.-----------.>.>-.<---------..>.<+++++.<---.>>+.<<+++++++.+.>-.>--.<----.<--------.>++.++.------.<++++.>++++.>.<+.+.<----.>.>++.<<+++++.>>+++++++++..---.-----.++++++++.------.++++.+..--.-----.+.-.<<---.>>++++++.-.+++..---.<<++.>>--.-.<<--.>>-.<<--.>>++++++.<<+++++.>>-----.+++++++.<<..>>++++++.<++++.>--.------------.+++++.------.>[[-]<]<

Passive HTTP monitoringand anomaly detection

Passive DNS data is used to identify DGA malware C2 servers

Useful resources

https://github.com/xoseperez/Brainfuck-Code-Generator — Generator and Intepreter of Brainfuck code.

Date post:	19-Mar-2016
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Detecting network attacks with mathematical methods and OCR algorithms With novel case studies :)

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