Functions/Test-JsonWebToken.ps1
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function Test-JsonWebToken { <# .SYNOPSIS Validates a JSON Web Token. .DESCRIPTION Validates a JSON Web Token signature and date range. If the SkipExpirationCheck parameter is used then only the token signature is validated. .PARAMETER JsonWebToken The JSON Web Token that is to validated. .PARAMETER HashAlgorithm The hash algorithim for the signature. Acceptable values are SHA256, SHA384, and SHA512. Default value is SHA256. .PARAMETER VerificationCertificate The certificate containing the public key that will be used to verify the signature of the JSON Web Token. .PARAMETER Key The secret key used to validate an HMAC signature expressed as a string. .PARAMETER SecureKey The secret key used to validate an HMAC signature expressed as a System.Security.SecureString. .PARAMETER JsonWebKey The JSON Web Key (X509 certificate public key) to verify the signature of the JSON Web Token per RFC 7517. .PARAMETER Uri Specifies the Uniform Resource Identifier (URI) containing the JSON Web Keys to validate the JSON Web Token against. Can be a well-known OpenID Connect discovery endpoint or a link containing the JWKs directly. .PARAMETER SkipExpirationCheck Tells this function to verify the signature of the JWT only and not to evaluate token expiration. .EXAMPLE $signingCertThumbprint = "6C85DF2F915D0E28B719AEC188367092A0FD0CD2" $certPath = Join-Path -Path Cert:\LocalMachine\My -ChildPath $signingCertThumbprint $cert = Get-Item -Path $certPath $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCNTMjU2IjoiYklYZkw1RmREaWkzR2E3QmlEWndrcUQ5RE5JIn0.eyJHaXZlbk5hbWUiOiJUb255IiwiTmFtZUlkIjoidG9ueS5ndWltZWxsaUBmbWdsb2JhbC5jb20iLCJTdXJuYW1lIjoiR3VpbWVsbGkiLCJqdGkiOiIyOUM1NTkwMWRiZDE0NmJDYjA3MjM5MDg5ZDJmQzJGRCIsImlhdCI6MTQ2NzgyODg1NywibmJmIjoxNDY3ODI4ODU3LCJleHAiOjE0Njc4MjkxNTd9.DgdcHarlI6gi6A4uX3kfQEfXRtD4fORp1svlIE8M_Ynr4cGjfncMyNkhPSplREX2509-pjbf90BpDqCoveGuvXKnWYFnGkfH8Cad-1qmurPQMyx_LTBW0jaw9lI7mVRFyN-I2lC0bw4QjC7QWrWctUE_v-OMSQIrAoNbaAKTVWjAcFC2reQymLL0zvLJ9MJ0RV4kQWBqMBaye7BuEnRfiEicJ57lg7cGCge2jYNYFNL2lBrOblr0SS4p8SUzQ-5WXj3gMT9K75_ai3Mg4UCHTZ9DAIDP29jHRdX7YTACVagQDZDPuZB1coJiemaSEJGvrDtfLOuR-MnGkRwCa88wfw" Test-JsonWebToken -JsonWebToken $jwt -HashAlgorithm SHA256 -VerificationCertificate $cert Validates a JSON Web Token's structure and verifies the signature against the certificate found in the local machine store with a thumbprint of 6C85DF2F915D0E28B719AEC188367092A0FD0CD2. .EXAMPLE $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpYXQiOjE2MDU5ODU5NjUsIm5iZiI6MTYwNTk4NTk2NSwiZXhwIjoxNjA1OTg2MjY1LCJzdWIiOiJ0b255In0.8ReUtDR9hiFtvvZtbtAvD1s3IYmt7uhXdLQyXY1Q4UM" Test-JsonWebToken -JsonWebToken $jwt -HashAlgorithm SHA256 -Key "secretkey" -SkipExpirationCheck .EXAMPLE $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpYXQiOjE2MDU5ODY1ODgsIm5iZiI6MTYwNTk4NjU4OCwiZXhwIjoxNjA1OTg2ODg4LCJzdWIiOiJ0b255In0.L2-gWEAJvkb5UtPav_v8zqWplJkUVULX_-QOE3jVbqY" $secureStringKey = "secretKey" | ConvertTo-SecureString -AsPlainText -Force Test-JsonWebToken -JsonWebToken $jwt -HashAlgorithm SHA256 -SecureKey $secureStringKey -SkipExpirationCheck Validates an HMAC-SHA256 signature only (not date range check) against a JWT with the HMAC key passed as a SecureString. .EXAMPLE $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyIsImtpZCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyJ9.eyJpYXQiOjE2MTgyNTAzODksIm5iZiI6MTYxODI1MDM4OSwiZXhwIjoxNjE4MjU1MTg5LCJzdWIiOiJ0b255In0.X-RZm-3Hto5U-8Q-Wp1ggqWTFPkO5-Cz9lzoKsH5-1RR9GOrGPuWn-bjIv1YJ46h5Bw-KpiX-dOS47TAq2A0BWdAwczLVA6pzha1WswkT_u3cO1_KSoOjD9qFLjCgk-ns7A48iXpNcOoPBFXgfx8G0rRK68sSnokJ7N2NH-YNUOjg3U7DNJ_-iz8WZ5dNlOvpDsTy0BHMX-lho18sUmakUNpadJr-oD7BXIp--Z57UERBFibppaoxseYRo3VfmhgHibTxP-39mcxU6sH9a99fEEt80hj4w6rZobRxZV-pFPS22B8TBAfVf8L9faMLaXmgV7xtQohqQZgL6oKdJzFPQ" $jwk = ' { "kty": "RSA", "use": "sig", "e": "AQAB", "n": "0yvTvlqT5yrk6lDzmK5_i6e-NKW4Bw8J9U62rcWI4IAr-vKaNqitmSwVLr2jJu29xQ__W22iGu584A82AS5N5YrwA6Rek-7WuHinwupFtCN-cCTzJlAcXUxyU7H0LfFxsXS1LUxSl7F_liIKH81QFE5RvI97R9bmbCn_BXpK4pHnTBGJigA8gJQ0U__YFk7AOSFUBeursQfCVPID99FpQ6pyj-h9WgdOneAfWde4SM1Pnovw59T2UT-JO-ObA5WOtvl0xW21djhhBRusVGWJuncNElhhRpUqNSOcsNQVe026zw8dX1wiMs9migQmz_LokH1bHENIuybdK9xBhXRRbw", "kid": "2yCvZnk7k8W66wR2LXR9WCswhAc" } ' Test-JsonWebToken -JsonWebToken $jwt -HashAlgorithm SHA256 -JsonWebKey $jwk Verifies a JSON Web Token's digital signature against a JSON Web Key as well as determining that that token is not expired. .EXAMPLE $jwt = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyIsImtpZCI6IjJ5Q3Zabms3azhXNjZ3UjJMWFI5V0Nzd2hBYyJ9.eyJpYXQiOjE2MTgyNTAzODksIm5iZiI6MTYxODI1MDM4OSwiZXhwIjoxNjE4MjU1MTg5LCJzdWIiOiJ0b255In0.X-RZm-3Hto5U-8Q-Wp1ggqWTFPkO5-Cz9lzoKsH5-1RR9GOrGPuWn-bjIv1YJ46h5Bw-KpiX-dOS47TAq2A0BWdAwczLVA6pzha1WswkT_u3cO1_KSoOjD9qFLjCgk-ns7A48iXpNcOoPBFXgfx8G0rRK68sSnokJ7N2NH-YNUOjg3U7DNJ_-iz8WZ5dNlOvpDsTy0BHMX-lho18sUmakUNpadJr-oD7BXIp--Z57UERBFibppaoxseYRo3VfmhgHibTxP-39mcxU6sH9a99fEEt80hj4w6rZobRxZV-pFPS22B8TBAfVf8L9faMLaXmgV7xtQohqQZgL6oKdJzFPQ" $jwkUri = "https://app.mycompany.com/common/discovery/keys" Test-JsonWebToken -JsonWebToken $jwt -Uri $jwkUri -HashAlgorithm SHA256 -SkipExpirationCheck -Verbose Attempts to validate a JSON Web Token signature against a collection of JSON Web Keys in https://app.mycompany.com/common/discovery/keys and provides verbose output detailing what JWK was used to verify the signature. .OUTPUTS System.Boolean .LINK https://tools.ietf.org/html/rfc7519 https://tools.ietf.org/html/rfc7517 New-JsonWebToken #> [CmdletBinding()] [Alias('tjwt', 'ValidateJwt')] [OutputType([System.Boolean])] Param ( [Parameter(Mandatory = $true, ValueFromPipeline = $false, Position = 0)] [ValidateLength(16, 8192)][Alias("JWT", "Token")][String]$JsonWebToken, [Parameter(Mandatory = $false, Position = 2)] [ValidateSet("SHA256", "SHA384", "SHA512")] [String]$HashAlgorithm = "SHA256", [Parameter(Mandatory = $true, ParameterSetName = "RSA", Position = 3)][Alias("Certificate", "Cert")] [ValidateNotNullOrEmpty()][System.Security.Cryptography.X509Certificates.X509Certificate2]$VerificationCertificate, [Parameter(Mandatory = $true, ParameterSetName = "HMAC", Position = 3)] [ValidateLength(4, 32768)] [String]$Key, [Parameter(Mandatory = $true, ParameterSetName = "HMACSecure", Position = 3)] [ValidateNotNullOrEmpty()] [System.Security.SecureString]$SecureKey, [Parameter(Mandatory = $true, ParameterSetName = "JWK", Position = 3)][Alias("jwk")][ValidateLength(12, 1073741791)][String]$JsonWebKey, [Parameter(Mandatory = $true, ParameterSetName = "URI", Position = 3)][Alias('OidcUri', 'JwkUri')][System.Uri]$Uri, [Parameter(Mandatory = $false, Position = 4)] [Switch]$SkipExpirationCheck ) BEGIN { $decodeExceptionMessage = "Unable to decode JWT." $ArgumentException = New-Object -TypeName ArgumentException -ArgumentList $decodeExceptionMessage } PROCESS { [bool]$jwtIsValid = $false [bool]$signatureIsValid = $false [bool]$tokenIsNotExpired = $false [bool]$hasValidJwtStructure = Test-JwtStructure -JsonWebToken $JsonWebToken -VerifySignaturePresent if (-not($hasValidJwtStructure)) { Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } [string]$missingDateExceptionMessage = "Unable to validate token lifetime due to missing exp claim in payload. If signature validation only is required use the SkipExpirationCheck parameter." # Verbose messages: [string]$sigValidMessage = "Signature was verified." [string]$sigInvalidMessage = "Signature was not verified." [string]$dateRangedValidMessage = "JWT date range is valid." [string]$dateRangedNotValidMessage = "JWT is expired." $headerTable = Get-JsonWebTokenHeader -JsonWebToken $JsonWebToken if ($null -ne $headerTable["kid"]) { $kid = $headerTable["kid"] $kidMessage = "Identifier of the signing key for the JWT: {0}" -f $kid Write-Verbose -Message $kidMessage } if ($PSCmdlet.ParameterSetName -eq "RSA") { try { $signatureIsValid = Test-JwtSignature -JsonWebToken $JsonWebToken -HashAlgorithm $HashAlgorithm -VerificationCertificate $VerificationCertificate -ErrorAction Stop } catch { Write-Error -Exception $_ -Category InvalidResult -ErrorAction Stop } if ($PSBoundParameters.ContainsKey("SkipExpirationCheck")) { $jwtIsValid = $signatureIsValid } else { [bool]$tokenIsNotExpired = $false try { $tokenIsNotExpired = Test-JwtDateRange -JsonWebToken $JsonWebToken -ErrorAction Stop } catch { $ArgumentException = New-Object -TypeName System.ArgumentException -Argument $missingDateExceptionMessage Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } $jwtIsValid = $signatureIsValid -and $tokenIsNotExpired } } elseif ($PSCmdlet.ParameterSetName -eq "JWK") { try { $signatureIsValid = Test-JwtSignature -JsonWebToken $JsonWebToken -HashAlgorithm $HashAlgorithm -JsonWebKey $JsonWebKey -ErrorAction Stop } catch { Write-Error -Exception $_.Exception -Category InvalidResult -ErrorAction Stop } if ($PSBoundParameters.ContainsKey("SkipExpirationCheck")) { $jwtIsValid = $signatureIsValid } else { [bool]$tokenIsNotExpired = $false try { $tokenIsNotExpired = Test-JwtDateRange -JsonWebToken $JsonWebToken -ErrorAction Stop } catch { $ArgumentException = New-Object -TypeName System.ArgumentException -Argument $missingDateExceptionMessage Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } $jwtIsValid = $signatureIsValid -and $tokenIsNotExpired } } elseif ($PSCmdlet.ParameterSetName -eq "URI") { $jsonWebKeys = @() try { $jsonWebKeys += (Get-JwkCollection -Uri $Uri -AsJson -ErrorAction Stop) } catch { Write-Error -Exception $_.Exception -ErrorAction Stop } foreach ($jwk in $jsonWebKeys) { try { if (Test-JwtSignature -JsonWebToken $JsonWebToken -HashAlgorithm $HashAlgorithm -JsonWebKey $jwk -ErrorAction Stop) { $signatureIsValid = $true $jwkValidMessage = "Verified signature against the following JWK: {0}" -f $jwk Write-Verbose -Message $jwkValidMessage break } else { $jwkInvalidMessage = "Unable to verify signature against the following JWK: {0}" -f $jwk Write-Verbose -Message $jwkInvalidMessage } } catch { Write-Error -Exception $_.Exception -Category InvalidResult -ErrorAction Stop } } if ($PSBoundParameters.ContainsKey("SkipExpirationCheck")) { $jwtIsValid = $signatureIsValid } else { [bool]$tokenIsNotExpired = $false try { $tokenIsNotExpired = Test-JwtDateRange -JsonWebToken $JsonWebToken -ErrorAction Stop } catch { $ArgumentException = New-Object -TypeName System.ArgumentException -Argument $missingDateExceptionMessage Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } $jwtIsValid = $signatureIsValid -and $tokenIsNotExpired } } else { # Parameter set is HMAC or HMACSecure if ($PSCmdlet.ParameterSetName -eq "HMACSecure") { try { $signatureIsValid = Test-JwtSignature -JsonWebToken $JsonWebToken -HashAlgorithm $HashAlgorithm -SecureKey $SecureKey -ErrorAction Stop } catch { Write-Error -Exception $_ -Category InvalidResult -ErrorAction Stop } } else { try { $signatureIsValid = Test-JwtSignature -JsonWebToken $JsonWebToken -HashAlgorithm $HashAlgorithm -Key $Key -ErrorAction Stop } catch { Write-Error -Exception $_ -Category InvalidResult -ErrorAction Stop } } if ($PSBoundParameters.ContainsKey("SkipExpirationCheck")) { $jwtIsValid = $signatureIsValid } else { [bool]$tokenIsNotExpired = $false try { $tokenIsNotExpired = Test-JwtDateRange -JsonWebToken $JsonWebToken -ErrorAction Stop } catch { $ArgumentException = New-Object -TypeName System.ArgumentException -Argument $missingDateExceptionMessage Write-Error -Exception $ArgumentException -Category InvalidArgument -ErrorAction Stop } $jwtIsValid = $signatureIsValid -and $tokenIsNotExpired } } if (-not($PSBoundParameters.ContainsKey("SkipExpirationCheck"))) { if ($tokenIsNotExpired) { Write-Verbose -Message $dateRangedValidMessage } else { Write-Verbose -Message $dateRangedNotValidMessage } } if ($signatureIsValid) { Write-Verbose -Message $sigValidMessage } else { Write-Verbose -Message $sigInvalidMessage } return $jwtIsValid } } |