Discovery / credits: Malvuln (John Page aka hyp3rlinx) (c) 2024
Original source: https://malvuln.com/advisory/0eb4a9089d3f7cf431d6547db3b9484d.txt
Contact: malvuln13@gmail.com
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 successfully 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;
}


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