Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2022 Original source: https://malvuln.com/advisory/d871836f77076eeed87eb0078c1911c7_B.txt Contact: malvuln13@gmail.com Media: twitter.com/malvuln Threat: Trojan.Win32.Autoit.fhj Vulnerability: Named Pipe Null DACL Family: Autoit Type: PE32 MD5: d871836f77076eeed87eb0078c1911c7 Vuln ID: MVID-2022-0638 Disclosure: 09/06/2022 Description: The malware creates two processes "xservice.exe" and a child process "xps.exe". The process creates an IPC pipe with a NULL DACL allowing RW for the Everyone user group. RManFUSCallbackNotify32 RManFUSServerNotify32 \\.\Pipe\RManFUSCallbackNotify32 RW Everyone Local low privileged users can modify the DACL to remove rights for the Everyone users group, denying access to use the pipe for further RW interprocess communications. Exploit/PoC: #include "windows.h" #include "stdio.h" #include "accctrl.h" #include "aclapi.h" /* Trojan.Win32.Autoit.fhj.d871836f77076eeed87eb0078c1911c7 NamedPipe Exploit Deny Access to Everyone By Malvuln **/ #define VULN_TROJAN_PIPE "\\\\.\\pipe\\RManFUSCallbackNotify32" int main(void){ HANDLE hPipe = CreateFileA((LPCSTR)VULN_TROJAN_PIPE, GENERIC_WRITE | WRITE_DAC, 0, NULL, OPEN_EXISTING, NULL, NULL); PACL pOldDACL = NULL; PACL pNewDACL = NULL; if (hPipe == INVALID_HANDLE_VALUE){ printf("%d", GetLastError()); return 1; } if(GetSecurityInfo(hPipe, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, &pOldDACL, NULL, NULL) != ERROR_SUCCESS){ printf("%d", GetLastError()); return 1; } TRUSTEE trustee[1]; trustee[0].TrusteeForm = TRUSTEE_IS_NAME; trustee[0].TrusteeType = TRUSTEE_IS_GROUP; trustee[0].ptstrName = TEXT("Everyone"); trustee[0].MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE; trustee[0].pMultipleTrustee = NULL; EXPLICIT_ACCESS explicit_access_list[1]; ZeroMemory(&explicit_access_list[0], sizeof(EXPLICIT_ACCESS)); explicit_access_list[0].grfAccessMode = DENY_ACCESS; explicit_access_list[0].grfAccessPermissions = GENERIC_ALL; explicit_access_list[0].grfInheritance = NO_INHERITANCE; explicit_access_list[0].Trustee = trustee[0]; if(SetEntriesInAcl(1, explicit_access_list, pOldDACL, &pNewDACL) != ERROR_SUCCESS){ printf("%d", GetLastError()); return 1; } if(SetSecurityInfo(hPipe, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, pNewDACL, NULL) != ERROR_SUCCESS){ printf("%d", GetLastError()); return 1; }else{ printf("Trojan.Win32.Autoit.fhj PWNED!\n"); printf("By Malvuln\n"); } LocalFree(pNewDACL); LocalFree(pOldDACL); CloseHandle(hPipe); system("pause"); return 0; } 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).