This article applies to all TeamViewer users.
All TeamViewer versions use full encryption. Encryption is based on 4096bit RSA private/public key exchange and 256 Bit AES session encoding. This uses the same security level as https/SSL and is considered completely safe by today's standards.
The key exchange also guarantees that the data transfer is completely encoded from client to client and that any routers or servers in between (including our routers) are unable to read or analyze the data stream.
Security and privacy have always been a top priority during development.
We invite you to visit our TeamViewer Trust Center
This article is aimed at professional network administrators. The information in this document is of a rather technical nature. Based on this information, IT professionals will receive pictures of the security standards at TeamViewer and will have any concerns resolved before deploying our software. Please feel free to distribute this article to your customers in order to alleviate any possible security concerns.
If you do not consider yourself to be part of the target group,the soft facts in the section "The Company / the Software" will still help you get a clear picture of how we take security seriously.
The Company and the Software
TeamViewer GmbH was founded in 2005 and is based in southern Germany, in the city of Göppingen (near Stuttgart), with subsidiaries in Australia and the United States. We exclusively develop and sell secure systems for web-based collaboration. Within a short span of time, our Freemium licensing has led to rapid growth, with more than 200 million users of the TeamViewer software on more than 1.4 billion devices, in more than 200 countries around the globe. The software is available in more than 30 languages.
Our understanding of Security
TeamViewer is used by more than 30 million users at any given point any day.
These users are providing spontaneous support over the internet, accessing unattended computers (e.g. remote support for servers), and are hosting online meetings.
Depending on the configuration, TeamViewer can be used to remotely control another computer, as if one were sitting right in front of it.
If the user who is logged on to a remote computer is a Windows, Mac, or Linux administrator, this person will be granted administrator rights on that computer as well. It is clear that such powerful functionality over the potentially unsafe internet has to be protected against attacks with great scrutiny.
In fact, the topic of security dominates all of our development goals and is something we live and breathe in everything we do. We want to ensure access to your computer is safe and to protect our own interests: millions of users worldwide only trust a secure solution, and only a secure solution assures our long-term success as a business.
From our understanding, security management is unthinkable without an established quality management system.
TeamViewer GmbH is one of the few providers on the market that practices certified quality management in accordance with ISO 9001. Our quality management follows internationally recognized standards. We have our QM system reviewed by external audits on an annual basis.
External Expert Assessment
Our software, TeamViewer, has been awarded a five-star quality seal (maximum value) by the Federal Association of IT Experts and Reviewers (Bundesverband der IT- Sachverständigen und Gutachter e.V., BISG e.V.). The independent reviewers of the BISG e.V. inspect products of qualified producers for their quality, security, and service characteristics.
Currently, TeamViewer is used by more than a 200million users.
International top corporations from all kinds of industries (including such highly sensitive sectors as banking, finance, healthcare, and government) are successfully using TeamViewer.
We invite you to have a look at our references all over the internet, in order to gain a first impression of the acceptance of our solution. You’ll find that presumably most other companies had similar security and availability requirements before they -after an intensive examination - finally decided on TeamViewer.
To form your own impression though, please find some technical details in the rest of this document.
Creating a Session and Types of Connections
When establishing a session, TeamViewer determines the optimal type of connection. After the handshake through our master servers, a direct connection via UDP or TCP is established in 70% of all cases (even behind standard gateways, NATs, and firewalls).
The rest of the connections are routed through our highly redundant router network via TCP or http-tunneling.
You do not have to open any ports in order to work with TeamViewer!
As described in the next paragraph Secure Connections, not even we, as the operators of the routing servers, can read the encrypted data traffic.
TeamViewer traffic is secured using RSA public/private key exchange and AES (256 bit) session encryption. This technology is used in a comparable form for https/TLS and is considered completely safe by today's standards.
As the private key never leaves the client computer, this procedure ensures that interconnected computers, including the TeamViewer routing servers, cannot decipher the data stream. Each TeamViewer client has a Certificate of the master cluster and can thus verify certificates of the TeamViewer system.
These certificates are used in a handshake between participants of the TeamViewer network. A simplified overview of this handshake can be seen in the following diagram.
The session key derived from this handshake is afterward used to encrypt the communication between parties using AES.
During TeamViewer's password authentication, no password equivalent data is shared because the Secure Remote Password (SRP) protocol version 6 is used.
Only a password verifier is stored on the local computer. For more details check the section TeamViewer Account.
Validation of TeamViewer IDs
TeamViewer IDs are based on various hardware and software characteristics and are automatically generated by TeamViewer. The TeamViewer servers check the validity of these IDs.
Prospective customers who inquire about the security of TeamViewer regularly ask about encryption. Understandably, the risk that a third party could monitor the connection or that the TeamViewer access data is being tapped is feared most. However, the reality is that rather primitive attacks are often the most dangerous ones.
In the context of computer security, a brute-force attack is a trial-and-error-method to guess a password that is protecting a resource. With the growing computing power of standard computers, the time needed for guessing long passwords has been increasingly reduced.
As a defense against brute-force attacks, TeamViewer exponentially increases the latency between connection attempts. It thus takes as many as 17 hours for 24 attempts. The latency is only reset after successfully entering the correct password.
TeamViewer not only has a mechanism in place to protect its customers from attacks from one specific computer but also from attackers controlling a large number of computers trying to access a specific target computer, e.g. using a botnet.
As an additional security feature, all of our software is signed via DigiCert Code Signing. In this manner, the publisher of the software is always readily identifiable. If the software has been changed afterward, the digital signature automatically becomes invalid.
Datacenter & Backbone
To provide the best possible security and availability of the TeamViewer services, all TeamViewer servers are located in data centers that are compliant with ISO 27001, leverage multi-redundant carrier connections and redundant power supplies. Furthermore, only state-of-the-art hardware is used. Additionally, all servers that store sensitive data are located within Germany or Austria.
Being ISO27001-certified mean that personal access control, video camera surveillance, motion detectors, 24x7 monitoring, and on-site security personnel ensure access to the data center is only granted to authorized persons and guarantee the best possible security for hardware and data. There is also a detailed identification check at the single point-of-entry to the data center.
TeamViewer accounts are hosted on dedicated TeamViewer servers. For information on access control, please refer to Datacenter & Backbone above. For authorization and the Secure Remote Password protocol (SRP) version 6 is used. This protocol combines the advantages of conventional ways of password storage. We do not store any information on our servers that could be used by an attacker to authenticate as the given account. In addition, a password is never sent to our servers during the authentication. Instead, a proof is used that is only valid for the single authentication run and can't be reused afterward.
Data stored in the account, e.g. passwords, keys, chat logs, etc. are encrypted using a combination of RSA and AES, where the root key for the encryption is derived from the user's password. This ensures that an attacker without the password can not access the data stored in the account.
The TeamViewer Management Console is a web-based platform for user management, connection reporting, and managing Computers & Contacts.
It is hosted in ISO-27001 certified, HIPAA compliant data centers. All data transfer is through a secure channel using TSL(Transport SecurityLayer) encryption, the standard for secure Internet network connections. Sensitive data is stored using the same encryption and authentication mechanisms described for the TeamViewer Account.
From within the TeamViewer Management Console, users are able to define, distribute, and enforce setting policies for the TeamViewer software installations on devices that belong specifically to them.
Setting policies are digitally signed by the account that generates them. This ensures that the only account permitted to assign a policy to a device is the account to which the device belongs.
Application Security in TeamViewer
Block- and Allowlist
Especially when TeamViewer is used for unattended maintenance of a computer (i.e. nobody is in front of the computer), the Allowlist allows to tighten security. Using this option the number of people who can get access to the machine is limited and even if e.g. the password is stolen an attacker can't get access to the device.
The restrictions can either be done to allow only specific TeamViewer ID's or TeamViewer accounts to access the computer remotely. Allowlists can be managed using the Policies described in the Management Console section.
Chat messages and their history are end-to-end encrypted and stored in the TeamViewer account using RSA/AES as described in the chapter TeamViewer Account. Only participants in a chatroom or 1:1 chat can access the messages and history.
No Stealth Mode
There is no function that enables you to have TeamViewer running completely in the background.
Even if the application is running as a Windows service in the background, TeamViewer is always visible by means of an icon in the system tray. After establishing a connection there is always a small control panel visible above the system tray. Therefore, TeamViewer is intentionally unsuitable for covertly monitoring computers or employees.
This allows users to make sure that no sensitive data is shown on their screen during a TeamViewer session.
For spontaneous customer support, TeamViewer (TeamViewer QuickSupport) generates a random password that can be changed at any time. If your customer tells you their password, you can connect to their computer by entering their ID and password. Depending on the settings, a new password will be generated on the customer's computer either after a restart of TeamViewer, after the session, or when manually requested.
When using TeamViewer for unattended remote support (e.g. of servers), we recommend to
In the combination with the Two-Factor-Authentication, this protection covers accessing the account as well as any machine you are supporting via TeamViewer.
All passwords are verified using the same SRP protocol described in the "TeamViewer Account" section.
Incoming and Outgoing Access Control
You can individually configure the connection modes of TeamViewer. For instance, you can configure your remote support or meeting computer in a way that no incoming connections are possible.
Limiting functionality to those features actually needed always means limiting possible weak points for potential attacks.
Two Factor Authentication
TeamViewer assists companies with their HIPAA and PCI compliance requirements. Two-factor authentication adds an additional security layer to protect TeamViewer accounts from unauthorized access.
In addition to both username and password, the user must enter a code in order to authenticate. This code is generated via the time-based one-time password (TOTP) algorithm. Therefore, the code is only valid for a short period of time.
Through two-factor authentication and limiting access by means of whitelisting, TeamViewer assists in meeting all necessary criteria for HIPAA and PCI certification.
Both TeamViewer infrastructure and the TeamViewer Software is subject to penetration tests on a regular basis. The tests are performed by independent companies, specialized in security testing.