Certificate Transparency

Merkle Tree Certificates Proposed to Enable Lightweight Post-Quantum HTTPS in Chrome

Google Chrome developers, together with industry partners and the IETF PLANTS working group, are introducing Merkle Tree Certificates (MTC) as the first HTTPS change designed to address performance challenges of post-quantum cryptography. The new format replaces parts of traditional X.509 certificate chains with compact inclusion proofs inside a Merkle tree whose root is signed by a certificate authority. This approach significantly reduces the size of authentication data exchanged during TLS handshakes while preserving strong post-quantum security properties. MTC also enforces Certificate Transparency by design, making it impossible to issue a public certificate without recording it in a publicly verifiable log. Performance evaluations are currently underway with Cloudflare, and initial public MTC logs operated by experienced CT log providers are planned for early 2027. A dedicated post-quantum Chrome Root Store supporting only MTC is scheduled for the third quarter of 2027 and will run in parallel with the existing root store.

Dangling DNS Records Expose Companies to Subdomain Takeovers Years After Projects Shut Down

A marketing team requested reactivation of a three-year-old promotional landing page, only to discover that its domain now served an unrelated third-party website. The root cause was a forgotten CNAME record in the company's DNS zone that continued pointing to a project name on external hosting after the original service had been decommissioned. Because many hosting providers use wildcard DNS entries, standard availability checks and simple DNS resolution tests fail to detect that the target project no longer exists. Attackers who re-register the freed project name can then serve content under the company's legitimate subdomain, automatically obtaining valid TLS certificates and inheriting domain-wide cookies. The article details how such dangling records accumulate across infrastructure, marketing, and acquired company zones, and explains the concrete risks including cookie theft, bypass of Content-Security-Policy, and unauthorized domain ownership proofs. It concludes with a practical remediation workflow: export the full zone, assign owners to every record, validate external targets by application response rather than DNS resolution, and embed record removal into decommissioning procedures.

Android 17 Adds Local Network Protection and Strengthens Wi-Fi Privacy Controls

Android 17 introduces Local Network Protection, requiring apps to obtain explicit permission before scanning or connecting to devices on the same Wi-Fi network. The feature limits unauthorized discovery of TVs, cameras, printers, consoles and other local equipment that could previously be used to build detailed user profiles. The update also enables Encrypted Client Hello by default to hide domain names during HTTPS handshakes from network observers. Certificate Transparency is now activated by default to detect fraudulent or mis-issued certificates that could enable interception attacks. Additional safeguards block forced downgrades to insecure 2G networks often exploited by fake base stations for SMS-based fraud. These changes collectively reduce passive tracking and man-in-the-middle risks without disrupting legitimate local network functions such as media casting.

Trusting Russian Root Certificates and Monitoring Domestic CT Logs

The article examines risks associated with installing Russian root certificates issued by the Ministry of Digital Development. It explains how these certificates, when trusted, enable potential MitM attacks through TSPU infrastructure by allowing on-the-fly issuance of fraudulent certificates for foreign domains. Yandex Browser stands out by enforcing Certificate Transparency checks for domestic certificates, unlike other browsers that disable CT validation in the presence of added roots. Three primary domestic CT logs are maintained by Yandex, VK, and the Ministry, with log lists updated annually. A Python script is provided to query these logs directly and verify SCT inclusion for any certificate. The piece also notes limitations of existing web monitors such as ct.tlscc.ru when dealing with newer log endpoints.