Adversaries may abuse the
cron utility to perform task scheduling for initial or recurring execution of malicious code. The
cron utility is a time-based job scheduler for Unix-like operating systems. The
crontab file contains the schedule of cron entries to be run and the specified times for execution. Any
crontab files are stored in operating system-specific file paths.
An adversary may use
cron in Linux or Unix environments to execute programs at system startup or on a scheduled basis for persistence.
|S0401||Exaramel for Linux|
Review changes to the
|M1018||User Account Management||
|ID||Data Source||Data Component|
|DS0003||Scheduled Job||Scheduled Job Creation|
Monitor scheduled task creation from common utilities using command-line invocation. Legitimate scheduled tasks may be created during installation of new software or through system administration functions. Look for changes to tasks that do not correlate with known software, patch cycles, etc.
Suspicious program execution through scheduled tasks may show up as outlier processes that have not been seen before when compared against historical data. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as network connections made for Command and Control, learning details about the environment through Discovery, and Lateral Movement.