Tails is safer than any regular operating system. But Tails, or any software or operating system, cannot protect you from everything—even if they pretend to.

The recommendations below will keep you even safer, especially if you are at high risk.

Protecting your identity when using Tails

Tails is designed to hide your identity.

But some of your activities could reveal your identity:

  • Sharing files with metadata, such as date, time, location, and device information
  • Using Tails for more than one purpose at a time

Limitations of the Tor network

Tails usa la red Tor porque es la red más fuerte y popular para protegerse de la vigilancia y la censura.

But Tor has limitations if you are concerned about:

  • Hiding that you are using Tor and Tails
  • Protecting your online communications from determined, skilled attackers

Reducir los riesgos al utilizar equipos que no son de confianza

Tails puede ejecutarse de forma segura en una computadora que tenga un virus.

Pero Tails no siempre puede protegerte cuando:

  • Instalación desde una computadora infectada
  • Ejecutar Tails en una computadora con BIOS, firmware o hardware comprometidos

Because you always have to adapt your digital security practices to your specific needs and threats, we encourage you to learn more by reading the following guides:

Protegiendo tu identidad al usar Tails

Limpiar los metadatos de los archivos antes de compartirlos

Muchos archivos contienen datos ocultos o metadatos:

  • JPEG and other image files often contain information about where a picture was taken and which camera was used.

  • Office documents often contain information about their author, and the date and time the document was created.

To help you clean metadata, Tails includes mat2, a tool to remove metadata in a wide range of file formats.

Metadata has been used in the past to locate people from pictures they took. For an example, see NPR: Betrayed by metadata, John McAfee admits he's really in Guatemala.

Use Tails sessions for only one purpose at a time

If you use Tails sessions for more than one purpose at a time, an adversary could link your different activities together.

For example, if you log into different accounts on the same website in a single Tails session, the website could determine that the accounts are used by the same person. This is because websites can tell when 2 accounts are using the same Tor circuit.

To prevent an adversary from linking your activities together while using Tails, restart Tails between different activities. For example, restart Tails between checking your work email and your whistleblowing email.

We are not aware of any such attacks to deanonymize people online who used Tails for different purposes at a time.

If you worry that the files in your Persistent Storage could be used to link your activities together, consider using a different Tails USB stick for each activity. For example, use one Tails USB stick for your activism work and another one for your journalism work.

Limitaciones de la red Tor

Tails deja en claro que estás usando Tor y probablemente Tails

Todo lo que haces en Internet desde Tails pasa por la red Tor.

Tor and Tails don't protect you by making you look like any random Internet user, but by making all Tor and Tails users look the same. It becomes impossible to know who is who among them.

  • Your Internet service provider (ISP) and local network can see that you connect to the Tor network. They still cannot know what sites you visit. To hide that you connect to Tor, you can use ?Tor bridges.

  • The sites that you visit can know that you are using Tor, because the list of exit nodes of the Tor network is public.

Los controles parentales, los proveedores de servicios de Internet y los países con una fuerte censura pueden identificar y bloquear las conexiones a la red Tor que no utilizan puentes Tor.

Muchos sitios web te piden que resuelvas un CAPTCHA o bloquees el acceso desde la red Tor.

Los nodos de salida pueden interceptar el tráfico hacia el servidor de destino

Tor hides your location from destination servers, but it does not encrypt all your communication. The last relay of a Tor circuit, called the exit node, establishes the actual connection to the destination server. This last step can be unencrypted.

A Tor connection
goes through 3 relays with the last one establishing the actual connection
to the final destination

The exit node can:

  • Observe your traffic. That is why Tor Browser and Tails include tools, like HTTPS Everywhere, to encrypt the connection between the exit node and the destination server, whenever possible.

  • Pretend to be the destination server, a technique known as machine-in-the-middle attack (MitM). That is why you should pay even more attention to the security warnings in Tor Browser. If you get such a warning, use the New Identity feature of Tor Browser to change exit node.

Warning: Potential Security Risk

To learn more about what information is available to someone observing the different parts of a Tor circuit, see the interactive graphics at Tor FAQ: Can exit nodes eavesdrop on communications?.

Tor exit nodes have been used in the past to collect sensitive information from unencrypted connections. Malicious exit nodes are regularly identified and removed from the Tor network. For an example, see Ars Technica: Security expert used Tor to collect government e-mail passwords.

Adversaries watching both ends of a Tor circuit could identify users

A powerful adversary, who could analyze the timing and shape of the traffic entering and exiting the Tor network, might be able to deanonymize Tor users. These attacks are called end-to-end correlation attacks, because the attacker has to observe both ends of a Tor circuit at the same time.

No anonymity network used for rapid connections, like browsing the web or instant messaging, can protect 100% from end-to-end correlation attacks. In this case, VPNs (Virtual Private Networks) are less secure than Tor, because they do not use 3 independent relays.

End-to-end correlation attacks have been studied in research papers, but we don't know of any actual use to deanonymize Tor users. For an example, see Murdoch and Zieliński: Sampled Traffic Analysis by Internet-Exchange-Level Adversaries.

Reducir los riesgos al utilizar equipos que no son de confianza

Instala Tails desde una computadora en la que confíes

Tails te protege de virus y malware en tu sistema operativo habitual. Esto se debe a que Tails se ejecuta independientemente de otros sistemas operativos.

Pero su Tails podría estar dañado si lo instala desde un sistema operativo comprometido. Para reducir ese riesgo:

  • Siempre instale Tails desde un sistema operativo confiable. Por ejemplo, descarga Tails en una computadora sin virus o clona Tails de un amigo de confianza.

  • No conecte su memoria USB Tails mientras otro sistema operativo se esté ejecutando en la computadora.

  • Utilice su memoria USB Tails solo para ejecutar Tails. No uses tu memoria USB Tails para transferir archivos hacia o desde otro sistema operativo.

Si te preocupa que tu Tails pueda estar dañado, haz una actualización manual desde un sistema operativo confiable.

No conocemos ningún virus capaz de infectar una instalación de Tails, pero podría crearse uno en el futuro.

Ningún sistema operativo puede protegerte contra alteraciones de hardware

Su computadora podría verse comprometida si sus componentes físicos han sido alterados. Por ejemplo, si un keylogger se ha instalado físicamente en su computadora, sus contraseñas, información personal y otros datos escritos en su teclado podrían ser almacenados y accedidos por otra persona, incluso si está usando Tails.

Intente mantener su computadora en un lugar seguro. Las alteraciones de hardware son más probables en las computadoras públicas, en los cibercafés o bibliotecas, y en las computadoras de escritorio, donde es más fácil de ocultar un dispositivo.

Si le preocupa que una computadora pueda ser modificada:

  • Use a password manager to paste saved passwords. This way, you don't have to type passwords that might be visible to people or cameras near you.

  • Use the Screen Keyboard, if you are using a public computer or worry that the computer might have a keylogger.

Keyloggers are easy to buy and hide on desktop computers but not on laptops. For an example, see KeeLog: KeyGrabber forensic keylogger getting started.

Other hardware alterations are much more complicated and expensive to install. For an example, see Ars Technica: Photos of an NSA “upgrade” factory show Cisco router getting implant.

Ningún sistema operativo puede proteger contra ataques de BIOS y firmware

El firmware incluye el BIOS o UEFI y otro software almacenado en chips electrónicos en la computadora. Todos los sistemas operativos, incluido Tails, dependen del firmware para iniciarse y ejecutarse, por lo que ningún sistema operativo puede proteger contra un ataque de firmware. De la misma manera que un automóvil depende de la calidad de la carretera por la que circula, los sistemas operativos dependen de su firmware.

Mantener tu computadora en un lugar seguro puede proteger contra algunos ataques de firmware, pero algunos otros ataques de firmware se pueden realizar de forma remota.

Firmware attacks have been demonstrated, but are complicated and expensive to perform. We don't know of any actual use against Tails users. For an example, see LegbaCore: Stealing GPG keys/emails in Tails via remote firmware infection.