{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Certutil Encode\n",
    "Detects suspicious a certutil command that used to encode files, which is sometimes used for data exfiltration"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Rule Content\n",
    "```\n",
    "- title: Certutil Encode\n",
    "  id: e62a9f0c-ca1e-46b2-85d5-a6da77f86d1a\n",
    "  status: experimental\n",
    "  description: Detects suspicious a certutil command that used to encode files, which\n",
    "    is sometimes used for data exfiltration\n",
    "  references:\n",
    "  - https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/certutil\n",
    "  - https://unit42.paloaltonetworks.com/new-babyshark-malware-targets-u-s-national-security-think-tanks/\n",
    "  author: Florian Roth\n",
    "  date: 2019/02/24\n",
    "  logsource:\n",
    "    category: process_creation\n",
    "    product: windows\n",
    "    service: null\n",
    "  detection:\n",
    "    selection:\n",
    "      CommandLine:\n",
    "      - certutil -f -encode *\n",
    "      - certutil.exe -f -encode *\n",
    "      - certutil -encode -f *\n",
    "      - certutil.exe -encode -f *\n",
    "    condition: selection\n",
    "  falsepositives:\n",
    "  - unknown\n",
    "  level: medium\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-*', 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='process_command_line.keyword:(certutil\\ \\-f\\ \\-encode\\ * OR certutil.exe\\ \\-f\\ \\-encode\\ * OR certutil\\ \\-encode\\ \\-f\\ * OR certutil.exe\\ \\-encode\\ \\-f\\ *)')\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
}