email security

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What DMARC Protects You From, and What It Does Not
4 hours ago
- DMARC's actual scope is narrow: it only verifies whether the visible From domain authorized a message through aligned SPF/DKIM, not spam or phishing.
- Three key terms: SPF lists authorized sending servers, DKIM provides a cryptographic signature, and DMARC ties either back to the visible From address.
- Email has two 'from' addresses: envelope for routing and visible From for display; DMARC ensures authentication aligns with the visible one.
- DMARC records live in DNS; examples show SPF, DKIM, and DMARC record syntax.
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Shifting Cyber Norms: Microsoft security POST-ing to you - Bert Hubert's writings
7 days ago
- Microsoft's email security scanners now execute JavaScript in email links, including POST requests, breaking single-use sign-on links.
- Historically, GET requests were considered safe and idempotent, while POSTs had side effects and were avoided by scanners.
- Website operators must now design systems to handle repeated or fake confirmations from security scanners.
- Microsoft's actions represent a significant shift in cyber norms without transparency or warning to users.
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Make people pay to get into your inbox
19 days ago
- Captchainbox helps protect inboxes from AI spam by requiring unknown senders to solve a CAPTCHA or pay a fee to reach recipients.
- The service scans email metadata to build a trusted sender list without reading messages, ensuring trusted contacts and introductions bypass verification.
- It offers a 7-day free trial with features like real-time filtering, calendar protection, custom auto-replies, and archival of emails without deletion.
- Setup takes 5 minutes, with pricing per inbox, and fees from senders are pooled for donation.
DKIM2 and DMARCbis Have Landed
a month ago
- DKIM2 is a new version of DKIM that creates a verifiable chain of custody for emails, ensuring signatures remain valid through forwarding and preventing replay attacks.
- DMARCbis is the successor to DMARC, replacing the static Public Suffix List with a live DNS tree walk and retiring ineffective tags, while incorporating operational improvements.
- Stalwart v0.16.12 is the first mail server to fully implement both DKIM2 and DMARCbis, with a web-based playground for testing authentication without installation.
- DKIM2 addresses issues like replay attacks by including envelope information in signatures, and forwarding breakage via reversible recipes that allow verifiers to undo changes.
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email security

What DMARC Protects You From, and What It Does Not

Shifting Cyber Norms: Microsoft security POST-ing to you - Bert Hubert's writings

Make people pay to get into your inbox

DKIM2 and DMARCbis Have Landed