RE: Web Site Hacks

[Denis Gordon <denis () dcc govt nz>]

Edward Cracknell <edward () securIT net> said:

> Web Site Hacks:
>
> Phillip Mau <philbo () dmc net>  wrote:

[[  snip  ]]

> Assuming the Web server is behind the firewall and only http is
allowed:
> a) The ability to run cgi-bin scripts or html form processing in a way
> which will create an html page as output. (Many form-based pages take
> input and produce a page for output). As a result, it might be
possible
> to create a page that contains a URL like:
>
> <A HREF=telnet://target.system.behi nd.firewall> Click here </A>
>
> This would generally allow a telnet session from the web server to the
> target system and the firewall rules of ONLY http allowed through
would
> not stop this.

But the 'page' this cgi script produces would be sent back to the
browser. To be activated, the user at the browser has to click it. So
any connection to 'target.system.behind.firewall' would be from the
browser, not from the firewall.

Or have I missed something fundamental here?

Denis Gordon - <denis () dcc govt nz>