Hacklog Volume 1 Anonymity: it security & Ethical Hacking Handbook

particular vulnerability on the researchers GitHub page, which includes a proof-
of-concept and a technical explanation of the attack.
6.9.2 Controlling WebRTC
To  be  quite  honest,  the  WebRTC  is  not  so  good  at  all!  Personally,  I
recommend everyone disable it directly from the browser, using extensions/add-
ons like:
-
     
WebRTC  Network  Limiter  for  Chrome
[75]
,  ScriptSafe
[76]
 for  Opera  and
Chrome
-
Disable WebRTC Addon
[77]
for Firefox
With Firefox, you can also disable the feature directly from the browser, just
type
“about:config”
on
the
address
bar,
search
the
string
“media.peerconnection.enabled” and double-click to set its value to false.
6.10 Browser Fingerprinting
All the technologies we covered so far have been analyzed to show how they
can  become  a  security  problem  for  the  user.  Now  we  have  to  explain  that  all
these technologies together form the so-called browser fingerprinting.
The  term  fingerprinting  relates  to  a  unique  value  that  is  assumed  by  the
browser when the sum of all the related information take to a unique result. For
the  sake  of  clarity,  imagine  you  can  literally  disassemble  your  browser.  Each
part belongs to a puzzle, and if such puzzle has an unique sorting in its structure,
then  it  automatically  assumes  a  unique  identity;  if  you  are  matched  to  such
identity, no proxy/VPN/Tor will ever protect you. But what those parts are?
6.10.1 Defining the Browser Fingerprinting
First  of  all,  we  must  clarify  that  fingerprinting  is  an  extremely  complex
operation, and is only performed by purpose-specific pieces of software. When

---

we navigate the web, our browser leaves a channel “open”, allowing any site to
get the following information:
-
Resolution, color depth
-
Active plug-ins and the related versions
-
Current time and Timezone
-
WebGL Fingerprint
-
List of fonts in the Operating System
-
Current language
-
Operating System and version
-
     
User  Agent,  namely  the  browser  and  the  underlying  technology,  and  its
version
-
External devices, like a Touchpad
-
Use of AdBlock
-
... and all what we have already discussed of.
You will be amazed by knowing the amounts of information we release over
the websites we visit. If you wish, you can run a test on the Panopticlick site
[78]
,
developed by EFF. Using Opera on a freshly formatted OSX 10.11.5, the result
shows that the browser is unique across more than 139,000 tests (Figure 23).

---

Figure 23: results of a conventional Opera browser on Panopticlick

---

6.10.2 Defending yourself from Browser Fingerprinting
If  you  accurately  followed  each  single  recommendation  from  the  previous
topics,  your  browser  is  probably  quite  secure.  You  can  do  more,  however.  The
trick  is  changing  the  game,  handling  the  aforementioned  resources.  Each
browser  allows  some  “covering-up”,  such  as  changing  the  font  list,  disabling
plug-ins,  etc.  However,  this  topic  would  require  more  than  a  single  book!  You
can use some extensions/add-ons, though, for example:
-
FireGloves
[79]
, available for Mozilla Firefox
-
StopFingerprinting
[80]
, available for Google Chrome
6.11 File Downloading
This  category  includes  all  the  files  that  are  downloaded  but,  once  opened,
may  reveal  information  about  your  online  data.  When  you  need  to  open  any
files,  you  should  use  tools  like  a  Virtual  Machine  on  a  host  computer  not
connected  to  Internet.  Files  downloaded  from  the  Internet  may  contain
executable code capable of communicating outside the anonymous network: for
example,  with  the  proper  knowledge,  some  arbitrary  scripting  code  can  be
inserted  into  Word  or  PDF  files,  not  mentioning,  of  course,  the  classic
executables available for your operating system (.exe, .dmg, .sh and so on).
6.12 Browser Security Test
Browser Security is a very complex and ever changing topic, and requires an
extensive  knowledge  from  multiple  fields.  Currently,  the  most  complete  and
reliable tool to test your browser and its security is offered by BrowserSPY
[81]
,
allowing  to  verify  the  existence,  or  rather  the  exposition,  of  any  technology  in
the browser.
Using this tool is quite simple: each item on the left side of the screen will
open a technology summary tab, and a list of values exposed to the network. You
must  ensure  that  all  the  items  that  may  somehow  compromise  your  anonymity
are  properly  hidden,  possibly  exploring  the  ones  that  have  not  been  covered  in
this document.

---

7. Data Security
If,  despite  all  precautions,  somebody  is  accused  of  a  crime  –  something  I
would not want anybody to go through – all IT devices potentially leading to a
crime may be confiscated.
Computer forensics is the IT branch that studies methods and approaches to
find any data inside an IT device. Such field has been quite successful in recent
years: just think about the number of cases solved thanks a phone call, a picture
taken  by  a  smartphone  or  recovered  files  from  a  criminal’s  computer.
Furthermore,  it  has  deeply  changed  and  evolved:  until  a  couple  of  years  ago,
everything  was  confiscated  together  with  the  computers:  keyboards,  monitors
and mouse mats, and for no good reason!
Nowadays,  labs  and  highly  trained  personnel  are  involved  and  results  are
often excellent. The forensic research practices may be used by law enforcement
bodies – their actions are subject to the applicable laws – as well as by anyone
skilled  enough  to  perform  them.  As  we  will  see,  some  of  these  skills  can  be
easily learned and, except in rare cases, won’t require any particular tool. In this