Hypercorn

This brief details a behavioral detection strategy for identifying potential web shell deployment and persistence mechanisms by monitoring anomalous file creation activities originating from common web server processes on Linux.

This detection rule identifies suspicious child process executions originating from web server processes on Linux systems, indicating that attackers may have exploited web application vulnerabilities such as command injection or remote file inclusion to establish persistence or execute malicious commands.

This brief describes how attackers exploit vulnerabilities in web applications to execute suspicious shell commands via web server processes on Linux, enabling persistence, discovery, credential access, and reverse shell establishment, which can lead to full system compromise and data exfiltration.