Cybersecurity and email security teams faced a busy week as active exploitation targeted core infrastructure and widely used platforms. Cisco warned of a critical AsyncOS zero-day affecting Secure Email appliances, while SonicWall patched an SMA 100 flaw reportedly chained for root-level takeover. HPE fixed a maximum-severity OneView RCE issue. SoundCloud also confirmed a breach exposing user emails and profile data, alongside outages, VPN blocks, and follow-on disruption.
In the current digital environment, email continues to be a crucial means of communication for companies, while also being a prime target for cybercriminals. As phishing schemes, spoofing, and domain impersonation increase, it’s essential to prioritize the protection of your email systems. This is where the new advancements in DMARC Wizard come into play — robust tools aimed at enhancing and streamlining your email authentication process.
As you know, DNS is the foundation of your brand’s digital presence, so if anything goes wrong with the DNS or worse, if attackers manage to exploit its vulnerabilities, your entire online presence is put at stake.
Implementing DMARC setup is a key strategy to prevent email abuse, enhance deliverability, and protect your organization’s reputation. Understanding and deploying DMARC, SPF, and DKIM are essential for securing your domain, reducing authentication gaps, and ensuring compliance with modern email authentication standards used by services like Yahoo, Gmail, and Google.
The Simple Mail Transfer Protocol (SMTP) is the foundational communication protocol for sending electronic mail across the Internet. Developed by the Internet Network Working Group and standardized in multiple key RFCs—most notably RFC 5321—SMTP governs the process of email transmission between email clients, mail servers, and intermediary systems. As digital communication has become ubiquitous, SMTP’s importance in ensuring the reliable delivery of electronic messages cannot be overstated.
Is p=reject the ultimate DMARC policy? 5 situations in which you should implement it
by DuoCircle
Out of the three DMARC policies—“p=none”, “p=quarantine”, and “p=reject” each serves a different purpose and provides a different level of security. But when it comes to actively blocking emails that attempt to spoof your domain, the strictest policy, “p=reject,” is the best choice.
Selecting the right web-based email server is foundational for both businesses and individuals who rely on secure, efficient, and reliable email communication. Whether you need a robust business email solution, secure email for personal use, or scalable webmail for your growing team, examining the essential features is crucial.
Cyber incidents this week spanned operating systems, browsers, enterprise platforms, hardware, and developer tooling. Microsoft closed out the year patching 56 Windows flaws and three zero days, while Google rushed an emergency fix for an actively exploited Chrome bug. Fortinet, Ivanti, and SAP shipped critical updates for auth bypass and RCE risks, and new PCIe IDE weaknesses prompted firmware work from Intel and AMD. At the same time, a Gogs zero day and abused GitHub tokens highlighted ongoing threats to software supply chains.
DomainKeys Identified Mail (DKIM) is a well-established email authentication protocol designed to help organizations defend against email spoofing, phishing attacks, and business email compromise (BEC). When implemented correctly, DKIM authentication allows the recipient’s email server to verify that a signed email has genuinely originated from the stated domain and that its message content has not been tampered with during transit.
Sender Policy Framework (SPF) is a core email authentication protocol designed to enhance email security. SPF records play a crucial role in protecting domains from phishing, spoofing, and impersonation attacks by specifying which mail servers are authorized to send on behalf of a domain. When properly configured, SPF authentication significantly improves deliverability, helping emails avoid spam folders used by providers such as Gmail and Yahoo.
SPF records updated by Google: Here’s what domain owners need to know!
by DuoCircle
Does your SPF record include Google as an authorized sender? If yes, then you must be dependent on Google’s recommended ‘include:_spf.google.com’ entry to make the most out of the SPF protocol. Recently, this entry has been updated by Google. So, if your domain has outdated or custom configurations, then the latest update may cause certain issues. This blog aims to explore the update in detail and the tactics that can be used to avoid any potential email deliverability hassles.
What is MTA-STS (Mail Transfer Agent Strict Transport Security) and why do you need it?
by DuoCircle
We have heard so much about securing your outgoing emails, but the truth is, attackers can even enter your digital ecosystem through emails that are sent to your organization. This means your incoming emails are just as unsafe as your outbound ones.
DomainKeys Identified Mail (DKIM) is one of the most robust email authentication methods, helping organizations defend against email spoofing, phishing, and spam. By using cryptographic digital signatures and distributing public keys through DNS records, DKIM verifies that outgoing emails are authorized and tamper-free, which is critical for brand protection and maintaining user trust.
Cyber incidents this week hit emergency alerting, e-commerce, infrastructure, and app stacks. To start with, ransomware against the CodeRED platform disrupted local emergency notifications and exposed clear-text passwords. In another incident, a five-month breach at a major East Asian retailer affected tens of millions of customer accounts. Attackers exploited a command injection bug in Array Networks gateways, an admin takeover flaw in the King Addons WordPress plugin, and the React2Shell RCE vulnerability in React and Next.js.
Google Workspace helps businesses send emails every day, but keeping those emails safe is just as important as sending them. Gmail now strongly encourages domains to use DMARC, which tells mail servers how to treat suspicious messages. If you set it up correctly, your emails are more likely to reach inboxes and your brand stays protected.
Selecting a reliable partner for your email migration is a mission-critical decision for both individuals and organizations, whether you are overseeing a personal email migration, business email migration, or a large-scale enterprise email migration.
DomainKeys Identified Mail (DKIM) is a sophisticated email authentication protocol used to help combat email spoofing and to ensure message integrity between the email sender and the email recipient. At its core, DKIM works by adding a unique cryptographic digital signature—known as the DKIM signature—to every outgoing email. This DKIM signature is generated using a private DKIM key, which is securely stored by the email server or email sending platform.
DMARC (Domain-based Message Authentication, Reporting, and Conformance) is a crucial email security protocol that prevents email spoofing, phishing attacks, and business email compromise by ensuring that only authorized sources can send email on behalf of a domain. By leveraging SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail), DMARC builds on these foundational email authentication methods to provide domain owners with granular control and visibility over their email traffic.
The Difference Between ~all, -all, and +all in SPF
by DuoCircle
SPF is the foundation of your email authentication, as it tells the receiving servers, “these are the only servers and addresses allowed to send emails on our behalf.” So, when an email goes out from your side to a provider like Gmail or Microsoft Outlook, their servers pull out your SPF record to confirm if the email came from a server you actually approved. If the server matches one of the entries in the list, the email is delivered.
Cyber incidents this week included ToddyCat deploying new tools to steal email data, Harvard reporting a breach affecting its alumni community, and a vendor compromise at SitusAMC exposing corporate records tied to major banks. Alongside, Asahi confirmed data theft affecting two million individuals, and OpenAI disclosed limited user information exposure linked to a Mixpanel breach. Here are this week’s top headlines.
![Cisco AsyncOS Exploited, SonicWall SMA Fix, HPE OneView Patched – Cybersecurity News [December 15, 2025]](https://www.duocircle.com/wp-content/uploads/2025/12/spf-record-tester-3450.jpg)
![Microsoft 2025 Fixes, Chrome Zero-Day, Enterprise Security Flaws – Cybersecurity News [December 08, 2025]](https://www.duocircle.com/wp-content/uploads/2025/12/spf-record-3456.jpg)
![React2Shell RCE Threat, CodeRED Alert Disruption, Coupang Data Breach – Cybersecurity News [December 01, 2025]](https://www.duocircle.com/wp-content/uploads/2025/12/spf-record-generator-4560.jpg)
![ToddyCat APT Evolving, Harvard Breach Reported, SitusAMC Vendor Breach– Cybersecurity News [November 24, 2025]](https://www.duocircle.com/wp-content/uploads/2025/12/spf-validator-5634.jpg)