Tag Archives: Web of Trust

When Captain CAcert rescues the Notaries of the Round Table

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Today we are going on a little journey through time for a current occasion. Are you ready? Then jump into the fountain together with Frog King!

Many, many years ago, when grandmother was still a little girl, it may have been in 1995, a hardworking man named Mark Shuttleworth started a certificate issuing service in his poor parents’ garage, just like CAcert is one.

The name of this service was Thawte. Thawte was a great and important service. It is said that it covered half of the empire at that time. And because he was so old and so wise, he enjoyed some privileges. When Uncle Netscape, the browser, introduced new rules for certificates, Aunt Thawte, considering her age, only had to comply if she wanted to.

Now it was the case in those days that some people would have liked to send letters in an envelope. Good Aunt Thawte said: I have so many envelopes, I will give you some! And everyone who booked a free e-mail address with her got the certificate to wrap the messages as a gift. The Web of Trust was created to ensure that everything was above board and that the big bad wolf didn’t pretend to be one of the seven little goats. There, the letter writers met with the most trustworthy men and women of the entire empire for the knighting.

After the wizard Verisign took over Aunt Thawte’s service in 1999, the Web of Trust’s noble round table was abolished a few years later. Its members were very surprised to be thrown out of the castle just like that, since they had selflessly served the cause as noble knights and notaries.

However, it was a stormy time. And the storm wind blew a big sailing ship with full rigging from New South Wales, a spot of earth on a big island in the middle of the big, wide sea in the New World, across the ocean. Its name was emblazoned in gold letters on the stern: CAcert.

The captain held the wheel with both hands until the ship docked in a safe harbour. Immediately the crew rushed ashore to the desperate notaries and knights of the Thawte Round Table and offered to take them in their ship.

Numerous were those who gratefully accepted this offer, even more so when the captain said that he trusted Aunt Thawte. So it happened that large parts of Thawt’s Web of Trust were integrated into CAcert’s Web of Trust and the Thawte notaries became CAcert assurers. In a special program named Tverfiy, they could have their trust points transferred in 2009. Today, more than a decade later, CAcert is discontinuing the corresponding web site, after a long time since scattered notaries have joined CAcert’s community.

Further reading:
https://wiki.cacert.org/Tverify
https://en.wikipedia.org/wiki/Thawte#Web_of_Trust
old blog posts from the time

Efail: How you can still trust in GPG/PGP encryption

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Use a safe e-mail client

The EFAIL attacks exploit vulnerabilities in the OpenPGP and S/MIME standards to reveal the plaintext of encrypted emails. In a nutshell, EFAIL abuses active content of HTML emails, for example externally loaded images or styles, to exfiltrate plaintext through requested URLs.

However, according to the German Federal Office for Information Security, the e-mail encryption standards mentioned can be used securely if they are correctly implemented and configured.

There should be no problem, if you and your e-Mail partner use one of the green marked e-mail clients. Even if your client has a red flag, it can be sure; you may do some further research (f.eg. Mailpile). But, do you know the software, others are using? The incident once again demonstrates the importance of trust in communication. Further reading about CAcert’s Web of Trust.

The published vulnerabilities show in particular that, in addition to careful handling of the private key to be kept secret, the security of the e-mail programs used and their configuration can also be decisive.

  • Basically, do not display or generate e-mails in HTML format.
  • In particular, the execution of active content, i.e. display of e-mails in HTML format and reloading of external content, should be switched off.
  • If an e-mail provider offers the possibility to do this via the settings of its webmail application, appropriate measures should also be implemented here.
  • Some vendors will publish patches that either fix the EFAIL vulnerabilities or make them much harder to exploit. So, update your e-mail client and the encryption extension.

For sensitive information that must be sent by e-mail, the following procedure can be used: Decrypt S/MIME or PGP emails in a separate application outside of your email client. Decrypt incoming encrypted emails by copy&pasting the ciphertext into a separate application that does the decryption for you. That way, the email clients cannot open exfiltration channels. This is currently the safest option with the downside that the process gets more involved.

Webmail seams not to be under attack, neither Mailvelope or PEP. All of them are not affected. So, the conclusion should not be to uninstall encryption, but to review your e-mail client, update it and adjust the properties.

CAcert.org is a community-driven Certificate Authority that issues certificates to the public at large for free. These certificates can be used to digitally sign and encrypt email, authenticate and authorize users connecting to websites and secure data transmission over the internet. CAcert has more than 358 000 users, is operated by volunteers and financed by donations.

Further reading:
OpenPGP is safer than S/MIME (by GnuPG)