name: Suspicious File Write
id: 57f76b8a-32f0-42ed-b358-d9fa3ca7bac8
version: 3
date: '2019-04-25'
description: The search looks for files created with names that have been linked to
  malicious activity.
how_to_implement: You must be ingesting data that records the filesystem activity
  from your hosts to populate the Endpoint file-system data model node. This is typically
  populated via endpoint detection-and-response products, such as Carbon Black, or
  via other endpoint data sources, such as Sysmon. The data used for this search is
  typically generated via logs that report file system reads and writes. In addition,
  this search leverages an included lookup file that contains the names of the files
  to watch for, as well as a note to communicate why that file name is being monitored.
  This lookup file can be edited to add or remove file the file names you want to
  monitor.
type: ESCU
references: []
author: Rico Valdez, Splunk
search: '| tstats `security_content_summariesonly` count values(Filesystem.action)
  as action values(Filesystem.file_path) as file_path min(_time) as firstTime max(_time)
  as lastTime FROM datamodel=Endpoint.Filesystem by Filesystem.file_name Filesystem.dest
  | `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `drop_dm_object_name(Filesystem)`
  | `suspicious_writes` | `suspicious_file_write_filter`'
known_false_positives: It's possible for a legitimate file to be created with the
  same name as one noted in the lookup file. Filenames listed in the lookup file should
  be unique enough that collisions are rare. Looking at the location of the file and
  the process responsible for the activity can help determine whether or not the activity
  is legitimate.
tags:
  analytics_story:
  - Hidden Cobra Malware
  kill_chain_phases:
  - Actions on Objectives
  cis20:
  - CIS 8
  nist:
  - PR.PT
  - DE.CM
  security_domain: endpoint
  asset_type: Endpoint