LoFP / certain tools may create hidden temporary files or directories upon installation or as part of their normal behavior. these events can be filtered by the process arguments, username, or process name values.

Techniques

• T1564

Sample rules

Creation of Hidden Files and Directories via CommandLine

• source: elastic
• technicques:
  • T1564

Description

Users can mark specific files as hidden simply by putting a “.” as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion. This rule looks for hidden files or folders in common writable directories.

Detection logic

process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
process.working_directory in ("/tmp", "/var/tmp", "/dev/shm") and
process.args regex~ """\.[a-z0-9_\-][a-z0-9_\-\.]{1,254}""" and
not process.name in (
  "ls", "find", "grep", "git", "jq", "basename", "check_snmp", "snmpget", "snmpwalk", "cc1plus", "snap",
  "command-not-found"
)