Utilizzando il secondo metodo, molto più veloce e sbrigativo, si realizza un’hot-link, rimanderete sempre all’immagine che risiede sul server dove è ospitato il sito dove l’avete trovata.

In particolare, gli hot-link sono usati con immagini di grosse dimensioni provenienti da altri siti web. Tale procedura comporta un forte sfruttamento in termini di banda e risorse del server in cui sono realmente memorizzate e un utilizzo praticamente nullo del server che contiene il sito web visualizzato.

Tale procedura non è molto corretta e neppure gradita da molti siti, infatti l’utilizzo di hot-link viene spesso proibito, perche` ruba della banda, oltre che dello spazio e delle risorse da un server che non appartiene a chi realizza l’hot-link, e questo non è bello né certamente educato.

Vediamo ora con un esempio pratico perche` realizze un hot-link e` una gran brutta idea.

Un po’ di giorni fa vedo nei file di log di questo web server che e` stato realizzato un hot-link ad un’immagine che avevo postato tempo fa senza nemmeno citarmi come fonte. Oggi e` venerdi`, mi sento buono, e non riporto chi ha realizzato l’hot-link.

Non che a me interessi se mi ruba un po’ di banda o qualche ciclo di CPU, per mia fortuna questo server e` abbastanza sovradimensionato, ma vorrei spiegare cosa comporta quel hot-link e cosa poteva accedere, al di la` di qualche megabyte di banda.

1. Se fossi stato di fretta
   Se volevo risolvere velocemente la questione, rinomivavo o spostavo l’immagine. Il mio sito non avrebbe avuto problemi ma chi avrebbe visualizzato la pagina contentente l’hot-link non avrebbe visualizzato l’immagine, avrebbe ottenuto un errore di immagine mancante, e avrebbe dato la colpa ad un webmaster incompetente.
2. Se fossi stato professionale
   Se volevo risolvere la questione in modo professionale avrei aggiunto qualche riga per mod_rewrite come queste:

   RewriteEngine on
   RewriteCond %{HTTP_REFERER} !^$
   RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?miosito.it [NC]
   RewriteRule \.(jpg|jpeg|png|gif|bmp)$ - [NC,F,L]

   Cosi che tutti i visitatori che richiedessero l’immagine provenendo dal sito con l’hot-link non la visualizzassero. I visitatori avrebbero dato la colpa nuovamente al webmaster.

3. Se fossi stato vena di scherzi
   Avrei sostituito l’immagine con un altra. L’immagine oggetto del’hot-link e sul mio sito, quindi sotto il mio totale controllo. E posso farci quello che voglio, se fossi stato in vena di scherzi l’avrei sostituita con un immagine pornografico o di insulti verso i navigatori. Immagino che i visitatori del sito in cui viene visualizzata tale immagine non sarebbero molto felici, e se la prenderebbero con il webmaster di tale sito. E questo ne e` un esempio. (V.M. 27).
4. Se fossi stato cattivo
   Avrei fatto in modo di sostituire l’immagine con un mio script javascript. Questo sarebbe stato eseguito dal browser del visitatore del sito che mi hot-linka.
   A quello script potrei far fare molte cose, ad esempio far apparire come defacciato il sito al visitatore.
5. Se fossi veramente cattivo
   Avrei fatto in modo di sostituire l’immagine con un mio script javascript. Questo sarebbe stato eseguito dal browser del visitatore del sito che mi hot-linka.
   Tale javascript avrebbe mostrato l’immagine originaria, come nulle fosse, con la differenza che ad esempio richiamava attack-api, rubava le credenziali e dati di ogni visitatore del sito, e me le inviava. Ogni visitatore di quel sito sarebbe stato attaccato, la privacy della maggior parte di loro sarebbe stata violata e dei dati importanti sarebbere stati trafugati. Con un po’ di fortuna avrei rubato anche le credenziali dell’amministratore del sito che mi ha fatto l’hot-link.

Ora, siamo d’accordo che l’hot-link e` cosa brutta?

The Microsoft .NET framework comes with a request validation feature, configurable by the ValidateRequest setting. ValidateRequest has been a feature of ASP.NET since version 1.1. This feature consists of a series of filters, designed to prevent classic web input validation attacks such as HTML injection and XSS (Cross-site Scripting).

Procheckup describe how bypass ValidateRequest in a whitepaper.

On the other side, some ASP.NET controls offers by default automatic html encoding, a great resource when you are reviewing your code for possible Cross-Site Scripting (XSS) or double encoding problems is this table that list all ASP.NET control and which property offers html, script or url encoding.

You can read a detailed article of Trevor McCaulery here: http://www.adobe.com/devnet/flashplayer/articles/fplayer10_security_changes.html

It seems that the Adobe security is based on:

• require user interaction: to avoid automatic explotation and warn user about flash actions
• new features that ovverride olds with a more secure implemtation

After almost a year of extensive programming I am done with complete code refactoring, many bugs fixes and many new features.
Some of the new features include:

• Added multithreading support to set the maximum number of concurrent HTTP requests.
• Implemented SQL shell (–sql-shell) functionality and fixed SQL query (–sql-query, before called -e) to be able to run whatever SELECT statement and get its output in both inband and blind SQL injection attack.
• Added an option (–privileges) to retrieve DBMS users privileges, it also notifies if the user is a DBMS administrator.
• Added support (-c) to read options from configuration file, an example of valid INI file is sqlmap.conf and support (–save) to save command line options on a configuration file.
• Implemented support for HTTPS requests over HTTP(S) proxy.
• Enhanced logging system: added three more levels of verbosity to show also HTTP sent and received traffic.

Complete list of changes at http://sqlmap.sourceforge.net/doc/ChangeLog.

Information gathering

• Whois and geo-location
  • ShowIP
    : Show the IP address of the current page in the status bar. It also
    allows querying custom services by IP (right mouse button) and Hostname
    (left mouse button), like whois, netcraft.
  • Shazou
    : The product called Shazou (pronounced Shazoo it is Japanese for
    mapping) enables the user with one-click to map and geo-locate any
    website they are currently viewing.
  • HostIP.info Geolocation : Displays Geolocation information for a website using hostip.info data. Works with all versions of Firefox.
  • Active Whois : Starting Active Whois to get details about any Web site owner and its host server.
  • Bibirmer Toolbar
    : An all-in-one extension. But auditors need to play with the toolbox.
    It includes ( WhoIs, DNS Report, Geolocation , Traceroute , Ping ).
    Very useful for information gathering phase

• Enumeration / fingerprinting
  • Header Spy: Shows HTTP headers on statusbar
  • Header Monitor
    : This is Firefox extension for display on statusbar panel any HTTP
    response header of top level document returned by a web server.
    Example: Server (by default), Content-Encoding, Content-Type,
    X-Powered-By and others.

• Social engineering
  • People Search and Public Record:
    This Firefox extension is a handy menu tool for investigators,
    reporters, legal professionals, real estate agents, online researchers
    and anyone interested in doing their own basic people searches and
    public record lookups as well as background research.

• Googling and spidering
  • Advanced dork
    : Gives quick access to Google’s Advanced Operators directly from the
    context menu. This could be used to scan for hidden files or narrow
    in a target anonymously (via the scroogle.org option) 
  • SpiderZilla : Spiderzilla is an easy-to-use website mirror utility, based on Httrack from www.httrack.com.
  • View Dependencies
    : View Dependencies adds a tab to the "page info" window, in which it
    lists all the files which were loaded to show the current page. (useful
    for a spidering technique)

Security Assessment / Code auditing

• Editors
  • JSView
    : The ’view page source’ menu item now opens files based on the
    behavior you choose in the jsview options. This allows you to open the
    source code of any web page in a new tab or in an external editor.
  • Cert Viewer Plus
    : Adds two options to the certificate viewer in Firefox or Thunderbird:
    an X.509 certificate can either be displayed in PEM format (Base64/RFC
    1421, opens in a new window) or saved to a file (in PEM or DER format -
    and PKCS#7 provided that the respective patch has been applied - cf.
  • Firebug
    : Firebug integrates with Firefox to put a wealth of development tools
    at your fingertips while you browse. You can edit, debug, and monitor
    CSS, HTML, and JavaScript live in any web page
  • XML Developer Toolbar:allows XML Developer’s use of standard tools all from your browser.
  • Web developer : Adds a menu and a toolbar with various web developer tools.

• Headers manipulation
  • HeaderMonitor
    : This is Firefox extension for display on statusbar panel any HTTP
    response header of top level document returned by a web server.
    Example: Server (by default), Content-Encoding, Content-Type,
    X-Powered-By and others.
  • RefControl : Control what gets sent as the HTTP Referer on a per-site basis.
  • User Agent Switcher :Adds a menu and a toolbar button to switch the user agent of the browser

• Cookies manipulation
  • Add N Edit Cookies : Cookie Editor that allows you add and edit "session" and saved cookies.
  • CookieSwap
    : CookieSwap is an extension that enables you to maintain numerous sets
    or "profiles" of cookies that you can quickly swap between while
    browsing
  • httpOnly : Adds httpOnly cookie support to Firefox by encrypting cookies marked as httpOnly on the browser side
  • Allcookies : Dumps ALL cookies (including session cookies) to Firefox standard cookies.txt file

• Security auditing
  • HackBar
    : This toolbar will help you in testing sql injections, XSS holes and
    site security. It is NOT a tool for executing standard exploits and it
    will NOT learn you how to hack a site. Its main purpose is to help a
    developer do security audits on his code.
  • Tamper Data : Use tamperdata to view and modify HTTP/HTTPS headers and post
    parameters.
  • Chickenfoot
    : Chickenfoot is a Firefox extension that puts a programming
    environment in the browser’s sidebar so you can write scripts to
    manipulate web pages and automate web browsing. In Chickenfoot, scripts
    are written in a superset of Javascript that includes special functions
    specific to web tasks.

Proxy/web utilities

• FoxyProxy
  : FoxyProxy is an advanced proxy management tool that completely
  replaces Firefox’s proxy configuration. It offers more features than
  SwitchProxy, ProxyButton, QuickProxy, xyzproxy, ProxyTex, etc
• SwitchProxy:
  SwitchProxy lets you manage and switch between multiple proxy
  configurations quickly and easily. You can also use it as an anonymizer
  to protect your computer from prying eyes
• POW (Plain Old WebServer)
  : The Plain Old Webserver uses Server-side Javascript (SJS) to run a
  server inside your browser. Use it to distribute files from your
  browser. It supports Server-side JS, GET, POST, uploads, Cookies,
  SQLite and AJAX. It has security features to password-protect your
  site. Users have created a wiki, chat room and search engine using SJS.
• Torbutton : Torbutton provides a button to securely and easily enable or disable
  the browser’s use of Tor. It is currently the only addon that will
  safely manage your Tor browsing to prevent IP address leakage, cookie
  leakage, and general privacy attacks.

Misc

• Hacks for fun
  • Greasemonkey : Allows you to customize the way a webpage displays using small bits of JavaScript (scripts could be download here)

• Encryption
  • Fire Encrypter
    : FireEncrypter is an Firefox extension which gives you
    encryption/decryption and hashing functionalities right from your
    Firefox browser, mostly useful for developers or for education &
    fun.

• Malware scanner
  • QArchive.org web files checker
    : llowing people to check web files for any malware (viruses, trojans,
    worms, adware, spyware and other unwanted things) inclusions.
  • Dr.Web anti-virus link checker : This plugin allows you to check any file you are about to download, any page you are about to visit
  • ClamWin Antivirus Glue for Firefox : This extension scans every downloaded file automatically with ClamWin.

• Anti Spoof
  • refspoof
    : Easy to pretend to origin from a site by overriding the url referrer
    (in a http request). — it incorporates this feature by using the
    pseudo-protocol spoof:// .. thus it’s possible to store the information
    in a "hyperlink" - that can be used in any context .. like html pages
    or bookmarks