Invoice fraud doesn’t start with a Hollywood-grade hack. It starts with a believable message, a familiar vendor name, and a PDF that looks routine. Attackers know accounts payable runs on documents, so they hide social engineering and malware inside “invoice” attachments to reroute payments or plant a foothold. This guide lays out a practical, technical path to process PDF invoices safely—without turning your finance team into part-time security analysts.
DomainKeys Identified Mail (DKIM) is a critical component of modern email authentication frameworks designed to enhance email security by verifying sender identities and ensuring message integrity. Introduced as an open standard and formalized by RFC 6376, DKIM employs public key cryptography to cryptographically sign email headers and message body, allowing mailbox providers like Google’s Gmail, Microsoft 365, and Yahoo to verify that emails originate from legitimate senders.
Troubleshooting SPF syntax errors: Tips for fixing the most common mistakes
by DuoCircle
When you configure SPF for your domain, there are a lot of things that can go wrong and wreck your entire setup. And if your SPF configuration is not done right, your emails will be at risk, the risk of being rejected, marked as spam, or worse, being impersonated by threat actors.
An online SMTP server functions as a critical component of the email protocol infrastructure, facilitating the transfer of outgoing emails over the internet. SMTP, or Simple Mail Transfer Protocol, is the standardized protocol that governs how email servers, or mail transfer agents (MTAs), communicate to ensure reliable email delivery. Acting as an outgoing mail server, an SMTP server handles the sending process, routing emails through SMTP relay channels to the recipient’s email server.
This week saw a wave of cyber incidents across critical sectors. A stealthy campaign used the BRICKSTORM backdoor to hide inside networks for over a year, while a flaw in Pandoc was exploited in attempts to steal AWS credentials. Libraesva patched a bug in its Email Security Gateway that attackers are already abusing. Airports across Europe faced massive disruptions after a ransomware attack, and researchers flagged ShadowV2, a new Docker-targeting botnet offering DDoS-for-hire services.
Email hosting servers constitute the backbone of modern business communication infrastructure. At their core, these servers manage the sending, receiving, and storage of electronic mail by leveraging robust email server software. Their configuration involves the integration of various email protocols such as SMTP (Simple Mail Transfer Protocol), IMAP (Internet Message Access Protocol), and POP3 (Post Office Protocol 3), ensuring smooth mail routing between mail transfer agents (MTAs) and mail delivery agents (MDAs). Businesses depend on these servers to provide reliable communication channels facilitated through inbound mail servers, outbound mail servers, and mailboxes with efficient mailbox storage management.
When DKIM is not properly aligned for your domain, your outgoing emails may be at risk of tampering. That means anyone can make unauthorized changes to your email while it’s on the way to the receiver’s inbox, and the recipient might never even know it was altered.
Sender Policy Framework (SPF) is a critical email authentication protocol that plays a vital role in bolstering email security. Essentially, SPF allows domain owners to specify which mail servers are authorized to send emails on their behalf by publishing specific rules within DNS TXT records. This configuration helps receiving mail servers verify if incoming messages claiming to be from a particular domain are indeed sent from legitimate sources.
Why should you care about DMARC? What happens if you don’t?
by DuoCircle
Apart from the fact that most major email service providers and organizations have made DMARC mandatory, many teams enable it without fully understanding what it does or why it matters.
Cross tenant mailbox migration is a specialized form of tenant to tenant migration within Microsoft 365 environments, involving the transfer of mailboxes, shared mailboxes, public folders, and associated mailbox data between separate Office 365 tenants. This process is critical in multi-tenant environments where enterprises operate multiple Microsoft Exchange Online tenants, often due to mergers, acquisitions, divestitures, or organizational restructuring.
Cyber incidents this week underline just how disruptive attacks have become. One of the country’s biggest carmakers has kept its production lines shut, losing around 1,000 vehicles a day while work continues to restore systems. Investigators also uncovered a vast ad-fraud scheme that ran across 224 apps with 38 million downloads, generating more than two billion fake ad requests daily. Alongside that, a worm-like breach spread through hundreds of npm packages, while poisoned search results and phishing emails delivered remote-access malware to new victims.
DMARC best practices: Simple steps to protect your domain from email fraud
by DuoCircle
DMARC adoption is on the rise, especially since Google and Yahoo made it mandatory for bulk users. However, it is also true that many domain owners have not figured it out correctly because they don’t follow the best practices associated with it.
An SPF record, or Sender Policy Framework record, is a specific type of DNS TXT record published in the domain name system to improve email authentication and prevent email spoofing. The SPF record syntax defines which IP addresses and email servers are authorized to send emails on behalf of a domain, establishing an email sender policy that email servers can verify during delivery attempts.
Managed services refer to the proactive outsourcing of IT tasks and responsibilities to a third-party provider, enabling businesses to streamline their technology operations while focusing on core competencies. Unlike traditional IT outsourcing, which is often project-based or reactive, managed services emphasize ongoing infrastructure management, performance optimization, and proactive maintenance under a predefined service level agreement (SLA). This approach is designed to maximize system uptime, enhance security posture, and improve operational efficiency.
DomainKeys Identified Mail (DKIM) is a critical component of modern email security standards and plays a vital role in email authentication frameworks alongside Sender Policy Framework (SPF) and Domain-based Message Authentication, Reporting & Conformance (DMARC).
This week’s cyber reports reveal escalating threats on trusted platforms. A significant phishing attack on npm spread malware to millions, while a compromise of Salesloft’s GitHub account impacted the Drift application. Researchers also uncovered a malvertising campaign using fake GitHub commits and detailed the stealthy EggStreme framework, highlighting how attackers are exploiting familiar workflows with increasing sophistication and success.
Laposte.net’s 2025 email authentication shift: strategic insights and implementation best practices for enterprises
by DuoCircle
La Poste, France’s leading email service provider, which serves millions of users with private email addresses, has introduced mandatory email authentication requirements starting in September 2025. Now, what this means is that every email sent to Laposte.net addresses must pass SPF, DKIM, and DMARC authentication checks. If the senders don’t adhere to this, their emails will be relegated directly to spam.
In the realm of electronic communications, an email server is a critical component responsible for sending, receiving, and storing emails. At the core of email transmission lies the Simple Mail Transfer Protocol (SMTP), an essential set of rules that govern how outbound mail servers relay messages efficiently and securely. Within this infrastructure, the mail transfer agent (MTA) functions as the backbone, managing the routing and delivery of email through SMTP relays.
DomainKeys Identified Mail (DKIM) stands as a crucial pillar of email authentication and security. Defined under RFC 6376, DKIM is an email protocol that uses cryptography to sign email messages with a private key after leaving the mail client or mail server, specifically the mail transfer agent (MTA). The cryptographic signature included in the email headers enables receiving mail servers to perform signature verification by retrieving the corresponding public key from a DNS TXT record associated with the sender’s email domain.
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