Dennis Pellikaan Thijs Houtenbos · Automated vulnerability scanning and exploitation Dennis...

Automated vulnerability scanning and exploitation

Dennis Pellikaan Thijs Houtenbos

University of AmsterdamSystem and Network Engineering

October 22, 2013

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Introduction

Open Source scriptsShared on the internet, can be used by anyoneLots of attention for large projects (Wordpress, Joomla, etc)What about the rest?

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System overview

Completely automated system which gathers source code as inputand outputs a list of vulnerable servers.

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Sourceforge

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Github

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Github

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System parts

Collect a large number of projectsAnalyse code for possible vulnerabilitiesExploit the findings in a local environment to confirmSearch installations of the project onlineValidate the found installation matches the project

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Collect projects

Two sourcesSourceforgeGitHub

Focus on PHP scriptsAutomated download and extraction

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Collect projects

Collected projects

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Analyse code

SQL Injectionmysql_query ("SELECT * FROM users WHERE id=’$_GET[id]’");

File Inclusionrequire $_POST["lang_install"].".php";

Command Injectionexec ($_GET[’com’], $result);

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Regular Expressions

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Analyse projects

Vulnerable projects

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Analyse projects

Vulnerable projects

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Analyse projects

Vulnerability categories

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Exploit vulnerabilities

SQL Injectionmysql_query ("SELECT * FROM users WHERE id=’$_GET[id]’");

File Inclusionrequire $_POST["lang_install"].".php";

Command Injectionexec ($_GET[’com’], $result);

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Exploit vulnerabilities

SQL Injectionoverride_function (mysql_query, log_function);

Script sourcesmysql_query ("SELECT * FROM users WHERE id=’$_GET[id]’");

Executedlog_function ("SELECT * FROM users WHERE id=’$_GET[id]’");

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Exploit vulnerabilities

File Inclusionrequire $_POST["lang_install"].".php";log_function ($_POST["lang_install"].".php");

Command Injectionexec ($_GET[’com’], $result);log_function ($_GET[’com’], $result);

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Exploit vulnerabilities

Request the pagehttp://localhost/myscript/admin.php?id=hacklu

Log functionWrite the function arguments to a logfile

Logfileadmin.php:137 mysql_querySELECT * FROM users WHERE id =’hacklu’

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Exploit vulnerabilities

Request the pagehttp://localhost/myscript/admin.php?id=hack’lu

Log functionWrite the function arguments to a logfile

Logfileadmin.php:137 mysql_querySELECT * FROM users WHERE id =’hack’lu’

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Exploit vulnerabilities

Confirmation of results

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Search

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Search

Google Advanced Search Operators

allinurlpage.php: require $_GET[’page_id’];allinurl:"/page.php?page_id="allintitleindex.php: echo "<title>" . $title . "</title>";allintitle:"My special script v0.2a"

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Search

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Search

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Search

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Search

Rotate between 13 IPv4 addressesPause for 8 seconds between each request

20,000 search queries per day120,000 results with 22,000 queries

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Validate search results

Find the project’s installation rootIdentify six common file typesCompare locally identified files with the remote hostCalculate a score

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Validate search results

Installation root: deterministic approach

Google result: http://example.com/user/app/login.php?token=432

Local script Remote script/script/app/admin/login.php /example.com/user/app/admin/login.php/script/app/admin/ /example.com/user/app/admin//script/app/ /example.com/user/app//script/ /example.com/user/

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Validate search results

Installation root: probabilistic approach

Google result: http://example.com/user/app/guide.html

Local script/script/a/docs/examples/index.php/script/b/index.html/script/index.php/script/

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Validate search results

Common file types

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Validate search results

Comparing files

Local file Remote file/script/images/file1.gif /example.com/user/images/file1.gif/script/images/logo.png /example.com/user/images/logo.png/script/app/js/code.js /example.com/user/app/js/code.js/script/contact.html /example.com/user/contact.html

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Validate search results

Text matching

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Validate search results

Text matching

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Validate search results

MD5 Hash Matching

md5(Local File) 6= md5(Remote File)LocalScore = 0RemoteScore = 0

md5(Local File) = md5(Remote File)LocalScore = 100RemoteScore = 100

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Validate search results

Calculating the final score

Score between 0 and 100Number of identified files is taken into accountLocalScore and the RemoteScore are weighted

Score =∑N

i=1 SiN +

∑Ni=1 Si ∗ 1

6

Si = LocalScorei+RemoteScorei4

N = Total number of selected files

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Validate search results

Validated website scores

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Results

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System overview

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Questions

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Contact

Contact:Dennis: dennis.pellikaan@os3.nlThijs: thijs.houtenbos@os3.nl

Paper reference:http://rp.delaat.net/2012-2013/p91/report.pdf

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