Category Archives: security

Enable Keychain for SSH Connections after macOS Sierra

If you are connecting a lot from via SSH to remote servers, entering passphrases over and over might be a pain. As long as your hardware is secured, you might consider enabling the macOS keychain also for your SSH connections.

Go to ~/.ssh and open or create the config file. Now just enter the following entry to the file.

Host *
    UseKeychain yes

In the case you want to enable the keychain only for a certain server, simply replace * with your hostname such as

Prior to macOS Sierra, macOS offered a dialog to enter the passphrase where you were able to select the passphrase to be remembered. For some reason, this dialog was removed. On the other hand, the keychain option has been introduced with macOS 10.12.2.

WordPress Level Up – Applying Let’s Encrypt to Self-Hosted WordPress

Finally, I found some minutes to set up my website with SSL encryption. The issue here, many hosters demand a fortune for certificates. 

Applying Let’s Encrypt

Let’s Encrypt is a free alternative, providing certificates, accepted by most of the browsers.

While manually installing a certificate can be a real pain, Let’s Encrypt utilizes Certbot to do on your behave. Once installed you can select the sites to protect and let do Certbot its work. There is a crisp description on the Let’s Encrypt page which explains how this actually works.

To be honest, applying SSL certificate using this setup makes it absolutely easy for everybody to do so – as long as you have shell access on your server. After downloading the packages – which are provided for a variety of OS and Web server software – Certbot even takes care of the configuration.  You also can configure the sites in a way, that all HTTP requests are automatically are forwarded to HTTPS.

Once done, the site was already available via HTTPS. Unfortunately, Chrome told me the connection is still not secure.

The help provided did not help much either.

Further investigation eventually showed all images within posts did not use HTTPS even after the base URL of the site was changed in WordPress settings.

The links are not created on the fly – the are actually stored in the text. In the database. At least for internal resources (aka images from your own server), I expected something like relative links or similar. To be honest, I have never looked that much at the WordPress internals.

Altering the Database

To change this quickly, I decided to alter all not secure URLs in the database. As changing the protocol from HTTP to HTTPS is changing base URLs as when changing the domain, you could make use of tools to do so.

I found Misha Rudrastyh’s Query Generator very useful to create all SQL queries for changing the database content.

When moving WordPress websites from one domain to another, this tool is a great time saver. Just generate the queries and run them in MySQL.

In my case, I ended up with the following six statements.

UPDATE wp_options SET option_value = REPLACE(option_value, '', '') WHERE option_name = 'home' OR option_name = 'siteurl';
UPDATE wp_posts SET post_content = REPLACE (post_content, '', '');
UPDATE wp_postmeta SET meta_value = REPLACE (meta_value, '','');
UPDATE wp_comments SET comment_content = REPLACE (comment_content, '', '');
UPDATE wp_comments SET comment_author_url = REPLACE (comment_author_url, '','');
UPDATE wp_posts SET guid = REPLACE (guid, '', '') WHERE post_type = 'attachment';

Once done the next request already ended up in a valid and secure HTTPS request.

Warning: Do a backup (apply mysqldump) before altering your WordPress database, in case you brick it for whatever reason.


Using certificates issued by Let’s Encrypt you can automatically apply these by using Certbot to secure your website. While doing this I experienced some issues with WordPress as all URLs are stored as plain text in the database. With generated scripts from Misha Rudrastyh’s Query Generator altering the WordPress content to apply HTTPS instead of HTTP is quite easy.

Fixing the GPG Crash on Yosemite

Since upgrading to Yosemite, I have trouble running GPGMail with my Mac. When hitting the New Mail button Mail simply crashes.

GPG New MailThere is little I can do, and I almost gave up. The logs don’t help that much, though.

Crashed Thread:        0  Dispatch queue:

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000

Application Specific Information:
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<HeadersEditor 0x7fb0b6584680> valueForUndefinedKey:]: this class is not key value coding-compliant for the key _composeHeaderView.'
abort() called
terminating with uncaught exception of type NSException

However, there is this single thread in the GPG support forum, someone had the exact problem, while support pointed out there is some Yosemite beta of the GPG tools. Just in time,  GPG Suite Beta 4 was released, and it works like a charm.

GPG Suite Beta 4 workingIn case you are looking for the public key, pick it up here.