Bulletproof TLS Newsletter

Bulletproof TLS Newsletter is a free periodic newsletter bringing you commentary and news surrounding SSL/TLS and Internet PKI, designed to keep you informed about the latest developments in this space. Received monthly by more than 50,000 subscribers. Written by Hanno Böck.

The current Chrome version no longer loads mixed content on HTTPS connections. This change was announced by the Chrome security team last year and has now been implemented. Emily Stark from Chrome’s security team explains some of the details on Twitter.

When a web page is loaded via encrypted HTTPS to load subresources like images or videos via unencrypted connections, this is called mixed content. This can be a security risk because attackers can read and modify the unencrypted connections.

Browsers blocked active mixed content, including Javascript and CSS files, for many years. However, having passive content like images or videos as mixed content was still allowed.

Chrome changes this behavior now. If an HTTPS web page tries to load such content via HTTP, it will automatically try to load the content via HTTPS. If that doesn’t work, the loading is blocked. Mozilla plans to adopt this behavior as well, and there is work underway for standardizing it.

There is a special case in which mixed content warnings still appear: forms loaded from HTTPS web pages that have HTTP targets. Changes for this case are planned for version 87, including Chrome showing a warning while a user is typing into such forms and a full page warning before submission.

Short news

• Henry de Valence analyzed inconsistencies in the signature verification of Ed25519 signatures.
• The Internet Security Research Group (ISRG), wolfSSL, and Daniel Stenberg (the author of cURL) plan to work on a memory-safe HTTP implementation called Hyper. It will use Rustls as the TLS backend.
• OpenSSL released alpha 7 of the upcoming version 3.0.
• Mozilla released NSS version 3.58, including a security fix regarding ChangeCipherSpec (CCS) messages that could lead to denial of service. It also includes preliminary support for hybrid key exchanges, which will become important with the introduction of post-quantum cryptography.
• The Network Time Security (NTS) protocol, which provides authentication for NTP connections, is now officially published as an RFC.
• Chrony version 4.0 has been released. This is the first stable version supporting NTS.
• The Chrome team recently announced that it will run its own CA Root store.
• Google's Devon O'Brien summarized the results of the recent CT Days, discussing the future of Certificate Transparency.