IntroductionThis article is about HTML and Javascript injection techniques used to exploit web site vulnerabilities. Nowadays it's not usual to find a completely vulnerable site to this type of attacks, but only one is enough to exploit it.
I'll make a compilation of these techniques all together, in order to facilitate the reading and to make it entertaining.
HTML injection is a type of attack focused upon the way HTML content is generated and interpreted by browsers at client side.
Otherwise, Javascript is a widely used technology in dynamic web sites, so the use of technics based on this, like injection, complements the nomenclature of 'code injection'. Code injectionThis type of attack is possible by the way the client browser has the ability to interpret scripts embedded within HTML content enabled by default, so if an attacker embeds script tags such <SCRIPT>, <OBJECT>,<APPLET>, or <EMBED> into a web site, web browser's Javascript engine will execute it.
A typical target of this type of injection are forums, guestbooks, or whatever section where administrator allows the insertion of text comments; if the design of the web site isn't parsing the comments inserted and takes '<' or '>' as real chars, a malicious user could type : I like this site because <script>alert('Injected!');</script> teachs me a lot
If it works and you can see the message box, the door is opened to attacker's imagination limits!. A common code insertion used to drive navigation to another website is something like this: <H1> Vulnerability test </H1> <META HTTP-EQUIV="refresh" CONTENT="1;url=http://www.test.com"> Same within <FK> or <LI> tag : <FK STYLE="behavior: url(http://<<Other website>>;">Other tags used to execute malicious Javascript code are, for example, <BR>, <DIV>, even background-image:<BR SIZE="&{alert('Injected')}">
<DIV STYLE="background-image: url(javascript:alert('Injected'))">
<TITLE> tag is a common weak point if it's generated dynamically. For example, suppose this situation: <HTML>
<HEAD>
<TITLE><?php echo $_GET['titulo']; ?>
</TITLE>
</HEAD>
<BODY>
...
</BODY>
</HTML>Read more: Codeproject
I'll make a compilation of these techniques all together, in order to facilitate the reading and to make it entertaining.
HTML injection is a type of attack focused upon the way HTML content is generated and interpreted by browsers at client side.
Otherwise, Javascript is a widely used technology in dynamic web sites, so the use of technics based on this, like injection, complements the nomenclature of 'code injection'. Code injectionThis type of attack is possible by the way the client browser has the ability to interpret scripts embedded within HTML content enabled by default, so if an attacker embeds script tags such <SCRIPT>, <OBJECT>,<APPLET>, or <EMBED> into a web site, web browser's Javascript engine will execute it.
A typical target of this type of injection are forums, guestbooks, or whatever section where administrator allows the insertion of text comments; if the design of the web site isn't parsing the comments inserted and takes '<' or '>' as real chars, a malicious user could type : I like this site because <script>alert('Injected!');</script> teachs me a lot
If it works and you can see the message box, the door is opened to attacker's imagination limits!. A common code insertion used to drive navigation to another website is something like this: <H1> Vulnerability test </H1> <META HTTP-EQUIV="refresh" CONTENT="1;url=http://www.test.com"> Same within <FK> or <LI> tag : <FK STYLE="behavior: url(http://<<Other website>>;">Other tags used to execute malicious Javascript code are, for example, <BR>, <DIV>, even background-image:<BR SIZE="&{alert('Injected')}">
<DIV STYLE="background-image: url(javascript:alert('Injected'))">
<TITLE> tag is a common weak point if it's generated dynamically. For example, suppose this situation: <HTML>
<HEAD>
<TITLE><?php echo $_GET['titulo']; ?>
</TITLE>
</HEAD>
<BODY>
...
</BODY>
</HTML>Read more: Codeproject
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