Spam Campaign Abuses PHP Functions for Persistence, Uses Compromised Devices for Evasion and Intrusion

We found a spam campaign that uses compromised devices to attack vulnerable web servers. From the devices, attackers use a PHP script to send an email with an embedded link to a scam site to specific email addresses. The use of compromised devices for attacks make attribution difficult, and attackers can have repeated access to the server even after patching.