You might have been sending emails using Gmail for years now, but that’s not a good enough reason for the Email Service Provider (ESP) to let your email in, even if it feels like something’s off. Since email-based attacks are becoming so frequent and rampant, your sender reputation and good faith no longer suffice, given today’s threat landscape. That is why Gmail and other ESPs verify every email they receive before delivering it to the recipient’s inbox.
How cybercriminals use DNS hijacking to bypass DMARC policies
by DuoCircle
Email authentication protocols like SPF, DKIM, and DMARC are supposed to stop attackers from pretending to be you and dupe your clients. But what if they target the very system that these protocols depend on?
Logitech Data Breach, Mass Router Hijack, Android Trojan Sturnus – Cybersecurity News [November 17, 2025]
by DuoCircle
Here are this week’s cybersecurity updates, bringing you headlines that made news around the world. Princeton University reported a data breach impacting alumni and donors, and the Clop extortion gang’s activity continued, with Logitech confirming data theft linked to a third-party zero-day.
DuoCircle, LLC (“Company”) hereby provides formal notice that all data associated with the discontinued MailHostingService.com email hosting platform has been permanently and irreversibly destroyed in accordance with applicable data protection regulations and industry best practices.
Gmail enforcement norms for non-compliant emails: What’s new in 2025?
by DuoCircle
Email-based cyberattacks have become so severe and rampant that you can no longer afford to make email security an afterthought. Attackers out there are ready to seize even the most seemingly insignificant vulnerabilities at every chance they get. If your outgoing emails are not protected with email authentication protocols like SPF, DKIM, and DMARC, you are essentially making it easier for attackers to steal your confidential data, deceive your customers, and install malware on their systems.
How email authentication helps you prove sender identity under ISO 27001
by DuoCircle
Email is one of the main ways companies talk to customers, partners, and even their own teams. Because it is used so much, it also becomes an easy target for attackers who try to pretend to be someone else or steal important information. When a business wants to follow ISO 27001, it needs to show that its messages are safe and really coming from the right sender. That is where email authentication becomes helpful.
Cybersecurity headlines this week show a clear picture, and no one seems immune. Hyundai confirmed a data breach that may have exposed millions of Social Security numbers, and Google has gone on the offensive, suing a China-based group accused of running a billion-dollar phishing operation.
What happens when you misconfigure DKIM for your domain?
by DuoCircle
Your outgoing emails are only as safe as the configuration of your authentication protocols, like DKIM or DomainKeys Identified Mail. We say this because your emails are not inherently secure, which means anyone can intercept your outgoing emails and try to alter or impersonate them before they reach your recipients. This happens when you have not implemented DKIM at all or configured it incorrectly.
When I first started managing email campaigns, I spent hours crafting individual messages, manually segmenting lists, and tracking responses. This process was no walk in the park and left little to no room for strategic planning.
DomainKeys Identified Mail (DKIM) is a critical component of modern email authentication frameworks. As email threats such as phishing and spoofing continue to increase, leveraging a DKIM signature checker has become indispensable for organizations aiming to protect their domain reputation and ensure email deliverability.
Sender Policy Framework (SPF) records are an essential component of email authentication strategies designed to mitigate email spoofing and improve email security. These DNS TXT records specify which email servers are authorized to send outgoing email on behalf of your email domain.
Ensuring robust email security has become a pivotal concern for domain owners and organizations worldwide. Email threats such as phishing, spoofing attacks, and fraud are increasingly sophisticated, making proper email authentication protocols critical. Domain-based Message Authentication, Reporting & Conformance (DMARC) stands as a frontline defense mechanism, empowering organizations to protect their domains from email spoofing and improve overall email deliverability.
This week saw a surge in major cyber incidents worldwide. A ransomware attack crippled Japan’s Askul retail network, Qilin claimed Habib Bank AG Zurich, and Google uncovered AI-powered malware that rewrites its code. Cisco issued urgent fixes for firewall exploits, while Oglethorpe and NMHC disclosed healthcare data breaches.
How does BIMI complete the email authentication story?
by DuoCircle
Your emails are not inherently secure. This means when you send emails to your clients, there’s nothing in the default email protocol that guarantees the message actually came from you or wasn’t manipulated along its way.
As organizations continue to embrace the cloud, migrating to Microsoft 365 and Office 365 ecosystems has become a priority for seamless collaboration, enhanced security, and productivity. Office 365 migration involves transferring existing data—including emails, calendars, files, and user accounts—from legacy platforms or earlier Microsoft versions to cloud-based Microsoft 365 services such as Microsoft Teams, OneDrive, and SharePoint. This data migration process is critical for businesses aiming to leverage the extensive capabilities of Microsoft 365 apps like Outlook, Excel, and PowerPoint, while minimizing downtime and data loss.
In today’s fast-paced digital landscape, businesses must leverage efficient IT operations to stay competitive and responsive to market demands. Managed services have emerged as a strategic approach to outsourcing critical IT functions to specialized managed service providers (MSPs). This model empowers organizations to focus on core business objectives while ensuring robust IT infrastructure management, proactive IT strategy, and seamless service delivery.
DNS spoofing explained: what it is, how it works, and how to mitigate it
by DuoCircle
When your customers or clients type your website in the address bar, the internet does not recognize it as “yourcompany.com”; it actually looks for the numerical IP address that corresponds to that name. This happens through the Domain Name System (DNS), which is essentially like a directory of the internet.
DomainKeys Identified Mail (DKIM) stands as a pivotal technology within modern email authentication protocols, providing a robust mechanism for verifying the legitimacy of email messages. By enabling the signer—the sender’s authorized mail agent—to affix a cryptographic signature to emails, DKIM significantly improves email security and trustworthiness. The core premise involves associating a cryptographic signature with the signing domain, which recipients and verifiers can subsequently validate against a published public key in the Domain Name System (DNS).
This week’s cybersecurity highlights include a Chrome zero-day exploited by Memento Labs for spyware attacks, new npm supply chain threats like PhantomRaven and an info-stealer campaign, and active exploitation of DELMIA Apriso and XWiki flaws. Meanwhile, ransomware hit Sedgebrook and Heartland Health Center, exposing patient data and prompting renewed healthcare security concerns.
![Logitech Data Breach, Mass Router Hijack, Android Trojan Sturnus – Cybersecurity News [November 17, 2025]](https://www.duocircle.com/wp-content/uploads/2025/11/hosted-email-server-4002.jpg)
![Hyundai Leak Exposed, International Malware Bust, Lighthouse Phishing Lawsuit – Cybersecurity News [November 10, 2025]](https://www.duocircle.com/wp-content/uploads/2025/11/spf-record-check-3501.jpg)
![Askul Ransomware Disruption, Qilin Targets Habib, Google Exposes Malware – Cybersecurity News [November 03, 2025]](https://www.duocircle.com/wp-content/uploads/2025/11/spf-record-5602.jpg)
![Chrome Spyware Exploited, npm InfoStealer Attack, DELMIA XWiki Vulnerabilities – Cybersecurity News [October 27, 2025]](https://www.duocircle.com/wp-content/uploads/2025/11/spf-record-tester-6780.jpg)