HijackThis

- A general Homepage Hijacker Detector and Removal Tool

By: Tahira Farid

60-564 Project 1

Fall 2004

Overview

Browser Hijacking and Why The Techniques Preventing a Hijack HijackThis- A Hijack Removal Tool Download Information Getting around with the tool

Overview (cont.)

Testing Summary Important things learnt Useful Links References

What is Browser Hijacking?

Where browser’s default settings is forcibly modified by using scripting tools

Spyware takes over our internet settings, Redirects our searches and steals our homepage

adding links to favourites

changing homepage persistently - scripting- changing registry values- auto-running programs- secret files put on the hard disk

Why Hijacking?

Bring us back to a website or a sponsor’s site of Hijacker’s choice

Generate advertising revenues Keep users trapped in their sites Expand website’s traffic Is it Reversible?

-as easy as to switch the internet options back

-as crucial as to undo the changes by going to windows registry

The Techniques

Multiple Windows pop-ups while leaving the site Windows half off screen hard to close and allows no control Offering “freebies” in their sites Installing AOL software, messenger, ICQ adds http://

free.aol.com to IE’s trusted sites zone without our permission-can download activeX, run scripts, perform various actions.

Removing internet options from tool menu and control panel Changing reg settings to reset homepage Installing program to reset homepage on reboot

Preventing Hijack

Various anti-hijacking and anti-virus tools available.

HijackThis- utility tool to remove browser hijacks, viruses, trojans & spyware

Does not target specific prog./URLs Targets methods used by hijackers

HijackThis

Developed by Marijn Freeware 178 KB latest version: 1.98.2 Intended for advanced users Increasingly updated to detect & remove new

hijacks Runs on all windows OS

Download Info & caution

http://www.spychecker.com/program/hijackthis.html Required to place it in its own folder otherwise

backups will not be made. Recommended to be used after running spybot or

spyware/hijacker remover- malware files will be left behind.

Requires knowledge in windows and OS in general. If deleted entries without knowing- problems as IE

not working, running windows.

Caution (cont)

Scans registry and various files in HD. Entries similar to what a spyware/hijacker

program would leave behind Interpreting the results can be tricky. Legitimate programs get installed in similar

way hijackers get installed. Extra causion should be taken fixing a

problem.

Getting started

Go to the desired

folder where hijackthis

was created from zip

unpack. Double click

on hijackthis.exe

Scan results

Each line

starts with

a section

name

Info on selected items

To know info

about a

selected obj

Fix entries

Select an

item to

fix/remove

Restoring items deleted mistakenly

We can make

backup & restore

items for erroneous

scenarios for

items which were

removed but

legitimate. Under config

button

Generating startup listing

Has a built-in tool

to generate listing

of all the prog that

launch when comp

starts. Under config,

Misc tools option.

Process Manager

Built-in tool to

1) Kill processes that

are currently running

2) Check what DLLs

are loaded in a

particular process Under config,

Misc tools option

Process Manager (cont.)

Hosts File Manager

View our host file, Delete lines Toggle lines on/off HijackThis will

add a “#” sign

before the line

to comment it

out so that it will not

be used by Windows.

Delete on reboot

Sometimes files

obstinately reject

to get deleted from

the system by any

traditions means. Could be virus/

spyware HijackThis allows

windows to delete

the file on reboot.

HijackThis log

Each line on the

scan list starts

with a section name Each entry has a

2-letter code to say

what it is.

Testing

Windows XP SP2 Running spybot S&D, ad-aware Specific problem in IE: always redirects to http://213.159.117.134/index.php Even using spybot S&D, AboutBuster, Spywareblaster, Ad-aware

problem was still there Following entries were deleted after scan:

O2 - BHO: (no name) - {549B5CA7-4A86-11D7-A4DF-000874180BB3} - (no file)02 entries refers to BHO- plugins for browser that extend the functionality of it. Used by spyware & legitimate programs.CLSID refers to reg. entries that contains info about BHO/toolbars. This particular entry means the entry exists in the registry but the associated file does not exist. Therefore cleaned to tidy up the registry.

Testing (cont.)

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://213.159.117.134/index.php

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://213.159.117.134/index.php

R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://213.159.117.134/index.php

R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://213.159.117.134/index.php

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page = http://213.159.117.134/index.php

R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = http://213.159.117.134/index.php

R0,R1 entries refer to IE start page & search functions. The url R0, R1 are pointing to is unwanted. Therefore cleaned to get rid of it.

Testing (cont.)

O4 - HKLM\..\Run: [SysTime] startup item C:\WINDOWS\system32\systime.exe Trojan downloaded

O4 - HKCU\..\Run: [SysTime] C:\WINDOWS\system32\systime.exe

04 entries refer to app that are listed in certain keys in reg/startup folders and are loaded automatically when windows starts. Here 04 entry shows a CoolWebSearch Trojan. Therefore fixed by HijackThis. The corresponding file

C:\WINDOWS\system32\systime.exe

was deleted by running windows on safe mode after fixing with HijackThis.

Testing (cont.)

O16 - DPF: {15AD4789-CDB4-47E1-A9DA-992EE8E6BAD6} - http://public.windupdates.com/get_file.php...edceabcca450006

016 entries refer to ActiveX obj-programs that are downloaded from websites and stored in our computer. Also referenced in the reg by their CLSID.

Here the object/URL could not be recognized from where it was downloaded. Therefore cleaned by HijackThis. HijackThis also deletes the offending file from C:\Windows\Downloaded Program Files-where the these types of objects are stored.

Testing (cont.)

Booting with safe mode following file was deleted

C:\WINDOWS\system32\systime.exe Temp internet files were deleted System rebooted normally, Ad-aware was run to do

some more cleanup. No bad entries were found in the new log.

Summary

HijackThis is a very powerful tool to root out serious infestation or attack in our system.

we should be cautious enough, since incorrectly removing inappropriate objects can cause problems with legitimate programs and compromise our system.

Many online forums & tutorials for inspecting logfiles. Useful links available for CLSID, startup lists. we need a great deal of devotion, commitment and knowledge

towards our system security. HijackThis by itself can not make our system secure from

Hijackers, we need other relevant tools as well to detect and remove spyware and viruses.

Important things learnt

In order to keep computer clean and secure: Make our Internet Explorer more secure by customizing

security options. Use an AntiVirus Software Use Spyware & Malware remover utility tools

Spybot S&D, Ad-aware, CWShredder , HijackThis, SpywareBluster

Update our AntiVirus Software Use a Firewall Visit Microsoft's Windows Update Site Frequently Update all these programs regularly

Useful links

HijackThis log file analysis:

http://www.hijackthis.de/index.php?langselect=english TonyK's Browser Helper Obj (BHO) & Toolbar list:

http://www.sysinfo.org/bholist.php PacMan's Start-up list to find the entry and see if it's good or

bad.

http://www.sysinfo.org/bholist.php

References

http://www.spywareinfo.com/%7Emerijn/htlogtutorial.html

http://www.bleepingcomputer.com/forums/index.php?showtut orial=42#RDiag

Thank You!