Stay secure with the latest email security updates, best practices, and threat alerts to protect your inbox and sensitive information.
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Background for this topic.
Email is a system for exchanging digital messages, typically using mail servers and clients over a network. In security, it includes both the messages and the accounts, servers, domains, and authentication mechanisms that handle them. Email commonly carries phishing links, malicious attachments, and fraudulent requests for payments or credentials; compromised accounts can also be used to impersonate trusted people and conduct further attacks.
Defenses include filtering and malware scanning, phishing-resistant multifactor authentication, careful handling of links and attachments, and monitoring for unusual login or sending activity. Domain controls such as SPF, DKIM, and DMARC help receiving systems detect messages that are forged or sent without authorization, while encryption protects message contents in transit or at rest when correctly implemented. Security teams should preserve relevant headers and mailbox activity so suspicious messages can be investigated, removed, and used to identify affected accounts and other recipients.
Threat actors created and abused OAuth apps to access Microsoft's corporate email environment and remain there for weeks.
The Russian APT behind the SolarWinds attacks exfiltrated data from HPE email accounts last May.
Russian state-sponsored threat actor Nobelium used a basic password-spray attack to breach Microsoft corporate email accounts, including for execs.