Phishing via service is a social-engineering technique that delivers fraudulent messages through trusted platforms such as Microsoft Teams, Slack, email-like collaboration tools, or mobile messaging apps. Instead of relying on obvious spam, the attacker uses a place where employees already expect legitimate contact, making the lure feel routine and increasing the chance of interaction.
This matters because trusted services can bypass the caution people apply to unknown senders, and some security controls are weaker inside collaboration traffic than in traditional email filtering. Real attacks often use a fake login page, a malicious file, or a system-style prompt to steal credentials or push malware after the initial message. Defenders look for unusual sender relationships, external contacts in internal channels, suspicious links, rapid credential prompts, and account behavior that changes after a chat interaction. Logging from the collaboration platform, identity provider, and endpoint tools helps connect the message to the intrusion chain.