Spearphishing Link

What the technique is

Adversaries may send spearphishing emails with a malicious link in an attempt to gain access to victim systems. Spearphishing with a link is a specific variant of spearphishing. It is different from other forms of spearphishing in that it employs the use of links to download malware contained in email, instead of attaching malicious files to the email itself, to avoid defenses that may inspect email attachments. Spearphishing may also involve social engineering techniques, such as posing as a trusted source. All forms of spearphishing are electronically delivered social engineering targeted at a specific individual, company, or industry. In this case, the malicious emails contain links. Generally, the links will be accompanied by social engineering text and require the user to actively click or copy and paste a URL into a browser, leveraging User Execution. The visited website may compromise the web browser using an exploit, or the user will be prompted to download applications, documents, zip files, or even executables depending on the pretext for the email in the first place. Adversaries may also include links that are intended to interact directly with an email reader, including embedded images intended to exploit the end system directly. […]

What MITRE says you would watch

• AN0298

  Correlation of inbound emails with embedded links followed by user-driven browser navigation to suspicious or obfuscated domains. Detection chain includes malicious URL in email → user click recorded in Office logs → browser process spawning unusual child processes (e.g., PowerShell, cmd) or download activity.

• AN0299

  Detection of spearphishing links through mail logs and browser activity. Behavior includes email with suspicious URLs → user click recorded in mail/web proxy logs → shell or interpreter launched from browser process.

• AN0300

  Correlation of Mail.app logs with Safari/Chrome activity. Suspicious behavior includes email links → Safari/Chrome accessing newly registered or lookalike domains → osascript or Terminal spawned unexpectedly.