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Posts in 'Day-to-day security advice' category

The effect of cloud services on our intimacy with IT

Years ago, we did not trust cloud service providers, or we trusted them only when we had no choice. Then, consumers started using web-mail and other such services, and finally companies also moved into replacing their own IT with cloud applications. By now, we trust our service providers sufficiently, for the most part. We model our risks, we consider the benefits, and we usually decide that it’s worth it. But often enough, our trust in service providers still does not cause us the necessary warm and fuzzy feeling that is required for us to hand off all our data to the cloud and live a truly digital life. As it seems, thinking you are secure is one thing, and feeling you are sufficiently secure, even with your most critical data, is something else.

What do we do for now? – Use the cloud, but not for everything…

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On protecting yourself against MITM in SSH

SSH is one of the best security protocols out there. It is used by anyone remotely logging into servers, as well as for secure connection to Git servers, and for secure file transfers via SFTP. One of the key promises of SSH is protection against active man-in-the-middle attacks. This makes SSH the best choice when connecting to a server over a hostile network, such as over a public hotspot. However, some SSH clients (particularly on mobile phones) void this protection by not caching server keys. Can you do anything about it? Yes, use private-keys instead of passwords for client authentication. Read more (also) for the technical details.

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Using Tor to protect against certificate injection by Hotspots

Tor is typically used to attain anonymity and preserve privacy online. This is by far the most common and appealing use for it. Most people without such concerns are not likely to ever install a Tor browser on their workstations, and it’s a pity; Tor has at least one additional use-case which is applicable to a much larger audience. This use-case is the prevention of certificate injection when using untrusted network connections.

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Improving the security provided by Yubikey for local encryption

In the previous post, I discussed the use of Yubikey for local encryption. I noted that Yubikey can store a long string that can be used as an encryption key, or a password. It provides no extra protection against key-loggers, but still allows to use strong passwords without remembering and typing them. Today, I would like to discuss a technique that makes Yubikey based encryption more secure; still not resistant to a key-logger, but resistant to having the Yubikey “borrowed” by a thief.

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