{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Unauthorized System Time Modification\n",
    "Detect scenarios where a potentially unauthorized application or user is modifying the system time."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Rule Content\n",
    "```\n",
    "- title: Unauthorized System Time Modification\n",
    "  id: faa031b5-21ed-4e02-8881-2591f98d82ed\n",
    "  status: experimental\n",
    "  description: Detect scenarios where a potentially unauthorized application or user\n",
    "    is modifying the system time.\n",
    "  author: '@neu5ron'\n",
    "  references:\n",
    "  - Private Cuckoo Sandbox (from many years ago, no longer have hash, NDA as well)\n",
    "  - Live environment caused by malware\n",
    "  date: 2019/02/05\n",
    "  tags:\n",
    "  - attack.defense_evasion\n",
    "  - attack.t1099\n",
    "  logsource:\n",
    "    product: windows\n",
    "    service: security\n",
    "    definition: 'Requirements: Audit Policy : System > Audit Security State Change,\n",
    "      Group Policy : Computer Configuration\\Windows Settings\\Security Settings\\Advanced\n",
    "      Audit Policy Configuration\\Audit Policies\\System\\Audit Security State Change'\n",
    "    category: null\n",
    "  detection:\n",
    "    selection:\n",
    "      EventID: 4616\n",
    "    filter1:\n",
    "      ProcessName: C:\\Program Files\\VMware\\VMware Tools\\vmtoolsd.exe\n",
    "    filter2:\n",
    "      ProcessName: C:\\Windows\\System32\\VBoxService.exe\n",
    "    filter3:\n",
    "      ProcessName: C:\\Windows\\System32\\svchost.exe\n",
    "      SubjectUserSid: S-1-5-19\n",
    "    condition: selection and not ( filter1 or filter2 or filter3 )\n",
    "  falsepositives:\n",
    "  - HyperV or other virtualization technologies with binary not listed in filter portion\n",
    "    of detection\n",
    "  level: high\n",
    "\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Querying Elasticsearch"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Import Libraries"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from elasticsearch import Elasticsearch\n",
    "from elasticsearch_dsl import Search\n",
    "import pandas as pd"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Initialize Elasticsearch client"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "es = Elasticsearch(['http://helk-elasticsearch:9200'])\n",
    "searchContext = Search(using=es, index='logs-endpoint-winevent-security-*', doc_type='doc')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Run Elasticsearch Query"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s = searchContext.query('query_string', query='(event_id:\"4616\" AND (NOT (((process_path:\"C\\:\\\\Program\\ Files\\\\VMware\\\\VMware\\ Tools\\\\vmtoolsd.exe\" OR process_path:\"C\\:\\\\Windows\\\\System32\\\\VBoxService.exe\") OR (process_path:\"C\\:\\\\Windows\\\\System32\\\\svchost.exe\" AND SubjectUserSid:\"S\\-1\\-5\\-19\")))))')\n",
    "response = s.execute()\n",
    "if response.success():\n",
    "    df = pd.DataFrame((d.to_dict() for d in s.scan()))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Show Results"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "df.head()"
   ]
  }
 ],
 "metadata": {},
 "nbformat": 4,
 "nbformat_minor": 4
}