TROJAN:WIN32/ALYAK.B / Remote Stack Corruption

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

Discovery / credits: malvuln - (c) 2021 Original source: Contact: Media: Threat: Trojan:Win32/Alyak.B Vulnerability: Remote Stack Corruption Description: Read access violation results in stack corruption and crash. Specimen makes HTTP request for a plain text-file "1.txt" in the "images" directory Port 80. Point test machine gateway to a system you control and redirect DNS traffic for PoC. Send large payload of junk chars in server response for the requested "images/1.txt" file. Type: PE32 MD5: 6547f34243104ba6e21154ad96b799a5 Vuln ID: MVID-2021-0004 Dropped files: AYLaunch.exe ASLR: False DEP: False Safe SEH: True Disclosure: 01/01/2021 [+] Download advisory Memory Dump: 0:000> .ecxr eax=0019c7c4 ebx=00000000 ecx=00000000 edx=6d6d6d6d esi=76e34f60 edi=00000000 eip=6d6d6d6d esp=0019a3a4 ebp=6d6d6d6d iopl=0 nv up ei pl nz na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206 6d6d6d6d ?? ??? 0:000> .exr -1 ExceptionAddress: 6d6d6d6d ExceptionCode: c0000005 (Access violation) ExceptionFlags: 00000000 NumberParameters: 2 Parameter[0]: 00000000 Parameter[1]: 6d6d6d6d Attempt to read from address 6d6d6d6d dd 0019D3C4 0:000> dd 0019D3C4 0019d3c4 41414141 41414141 41414141 41414141 0019d3d4 41414141 41414141 41414141 41414141 0019d3e4 41414141 41414141 41414141 41414141 0019d3f4 41414141 41414141 41414141 41414141 0019d404 41414141 41414141 41414141 41414141 Exploit/PoC: python -c "print 'A'*60000" > 1.txt Start server. python -m http.server 80 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 occuring 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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