Knowledge Base

With TeamViewer policies it is possible to automatically upload remote control session recordings to a self-hosted or cloud-hosted SFTP storage. Storing recordings for later reviews can be useful for quality assessments, trainings, and auditing. This article explains how to set up the required TeamViewer policy rule(s) to achieve this. To learn more about how to initiate a recording of a remote control session, you can read this article.

This article applies to TeamViewer Tensor license holders using Windows and Linux.

Set up a TeamViewer policy

To configure your setup for the automatic remote control session recording upload you will have to create a new or update an existing TeamViewer policy and add the following policy rule(s). You can combine multiple policy rules within the policy to achieve your specific goal. Once the policy is then applied to the desired devices, the configuration will take effect. Learn how to apply a policy to your devices here.

The following guide will primarily focus on the setup for the Upload session recording to custom storage policy rule, which offers the capability to upload recordings to your SFTP server. There are two other rules that should be evaluated, as they further enhance control over when recordings are started and stopped.

Enforce auto recording of remote control sessions, which will automatically start recording as soon as an outgoing connection is made from the device with the policy applied. If you want to prevent the user in front of the device from stopping or pausing the recording before the remote control session ends, you can also add the Disable stopping and pausing session recordings policy rule. Both rules can be added and enabled without any further setup required.

How to set up the automatic recording uploads policy rule

When you add the Upload session recording to custom storage rule to your policy, there are a few required and optional fields to configure, which the following paragraphs will explain in more detail.

Required fields

Currently, only SFTP servers, which can be hosted in an on-premises data center or in a cloud-based environment such as Azure or Amazon Web Services, are supported as the Service Type.

There are two authentication types available:

• Password authentication

• Public key authentication

Choose your preferred option and verify that it is supported by your SFTP server or service. You should configure the new account and its authentication before continuing, because the password or private key are required in the next paragraphs.

Enter the Username of the account that should be used to authenticate with your server and upload the recording. Specify your Destination URL, which must be an SFTP URL targeting your server, including the path to the folder where the remote control session recordings should be uploaded. It is recommended that you minimize the permissions of the chosen account, granting only write access to the specific folder designated for uploading recordings.

Encrypted password or encrypted private key field

Only you and the uploading device can access the credentials of the SFTP account securely, and the password or private key needs to be encrypted using a user-defined certificate to deliver the credentials of the SFTP account securely.

The encrypted credentials will then be added into the policy rule as Encrypted password or Encrypted private key. The reason why you need a certificate for the encryption is that it will be rolled out to multiple devices later for the decryption. Your SFTP server will not handle the encrypted credentials, as the TeamViewer Application will decrypt them beforehand. It is recommended for this setup to have OpenSSL installed on your system.

There are many ways to generate certificates, depending on the operating system and the tools used. All of them should be viable, if the important parameters required for the x509 certificate are specified correctly:

• Key Usage: KeyEncipherment, DataEncipherment, KeyAgreement

• Type/Extended Key Usage: DocumentEncryptionCert, also known as 1.3.6.1.4.1.311.80.1

If you want to use self-signed certificates, then you can use the openssl req command (please find its documentation here), replacing <CertificateAndKeyName> with a name of your choice:

openssl req -x509 \

-newkey rsa:2048 \

-keyout <CertificateAndKeyName>.pem \

-out <CertificateAndKeyName>.crt \

-addext keyUsage='keyEncipherment, dataEncipherment, keyAgreement' \

-addext extendedKeyUsage='1.3.6.1.4.1.311.80.1'

This command will generate a certificate CRT and a private key PEM file, which are capable of encrypting and decrypting data. These files will have to be converted to PFX before they can be rolled out to Windows devices, which will be explained in a later paragraph.

Once you have your certificate file, you can verify its key parameters by running the following command, replacing <CertificateAndKeyName> with your real certificate, to check if it is compatible. This is especially important, if you want to verify whether an existing certificate or one from a third party can be used:

openssl x509 -text -in <CertificateAndKeyName>.crt

If your key generation was successful, you can then see the following lines within the output of your terminal. If they are not present, then the encryption and decryption of your credentials will fail.

X509v3 Key Usage: critical

Key Encipherment, Data Encipherment, Key Agreement

X509v3 Extended Key Usage:

1.3.6.1.4.1.311.80.1

Your chosen credential must be encrypted into the Cryptographic Message Syntax (CMS, you can read more about it in RFC 5652) using your certificate. This can be done by running the openssl cms command (please find its documentation here). For the following commands, you can also specify -out <FileName> to redirect the output from the terminal into a file instead.

To generate the Encrypted password, you will need to replace <Password> with the password of your SFTP server account and the <CertificateAndKeyName> with the name of your certificate file. Please use echo -n on Linux to avoid adding a new-line character at the end of your password:

echo "<Password>" | openssl cms -encrypt -outform PEM <CertificateAndKeyName>.crt

If you want to use the Encrypted private key instead, you will need to replace the <PathToPrivateKey> with the relative or absolute path to your private key of the SFTP server account.

openssl cms -encrypt -in <PathToPrivateKey> -outform PEM <CertificateAndKeyName>.crt

Once the credentials are successfully encrypted, the resulting output will look like the following example:

-----BEGIN CMS-----

MIIBwgYJKoZIhvcNAQcDoIIBszCCAa8CAQAxggFqMIIBZgIBADBOMDoxCzAJBgNVBAYTAkRFMSsw

(...)

hvcNAQcBMB0GCWCGSAFlAwQBKgQQddXx6ufF4KafytY5RKIZqYAQtpGNqX/eU+Oz+lxUnYUTJQ==

-----END CMS-----

Take the respective output of your chosen command and copy it over into the rule field, including the header and footer of the output that signify the beginning and end of the message.

The preparations for the policy rule using this certificate are done, but the generated PEM and CRT files are still required when the certificate is rolled out to the devices. There are additional optional fields in the policy rule that are explained in the following paragraphs.

Optional field

Download prefix URL is an optional field, that can be specified to offer direct downloads of recordings from your servers. This information is then available via our Web API (read more about it here), or in our integrations with Salesforce and ServiceNow. The field expects a web URL including the path, which contains your recordings. Since TeamViewer does not have any access to your storage, the recordings will need to retain their original name from the upload for the paths to stay valid.

While TeamViewer caches the public host-key of your SFTP server upon the first connection to check the server’s identity and prevent man-in-the-middle attacks, you can also specify it explicitly with the optional SSH public host-key setting, which is then used to verify the server identity instead. This is especially useful when you need to replace the host-key of your SFTP server at some point and tell the devices to expect a different host-key than they have initially cached.

In most cases, you can specify the public host-key during the setup of your SFTP server or you can look it up in the configuration files or the dashboards of your SFTP server. If you do not have access to these values, you can also get them from your current device.

In case you have connected to the server before using ssh, you can get it from the known_hosts file within your .ssh folder. Alternatively, you can use the following command, replacing <SftpServerDomain> with your server:

ssh-keyscan <SftpServerDomain>

When you copy over the host-key into the settings field, be sure that you only copy over the host key fingerprint, not the server’s name, IP address, key type or comment.

This concludes the setup of the policy setting. You can extend the policy with more settings or save it now.

Preparing and rolling out the certificate

For the TeamViewer application to be able to upload the remote control session recordings to the SFTP server, it needs to be able to decrypt the credentials. For this, the created certificate must be converted to the format of the receiving device's operating system, before they are rolled out. The same policy can be deployed to both Windows and Linux machines if the underlying keys are the same.