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CrowdStrike SIEM Connector Grok Rules

Steve Stonebraker posted this in Uncategorized on October 8th, 2019

I couldn’t find a good set of Grok rules for the CrowdStrike SIEM connector so I wrote my own.

You need two rule sets.

Set1:

%{IPV4:source_collector_ip} CEF: 0\|CrowdStrike\|FalconHost\|1.0\|%{WORD:event_type}\|%{GREEDYDATA:event_subtype}\|%{INT:event_tactic}\|externalId=%{HOSTNAME:externalID} cn2Label=%{WORD:cn2Label} cn2=%{WORD:cn2} cn1Label=%{WORD:cn1Label} cn1=%{WORD:cn1} dhost=%{HOSTNAME:dhost} duser=%{DATA:duser} msg=%{GREEDYDATA:msg} fname=%{DATA:fname} filePath=%{GREEDYDATA:filepath} cs5Label=%{DATA:cs5Label} cs5=%{GREEDYDATA:cs5} fileHash=%{DATA:fileHash} dntdom=%{DATA:dntdom} cs6Label=%{DATA: cs6Label} cs6=%{GREEDYDATA:cs6} cn3Label=%{DATA: cs3Label} cn3=%{DATA:cn3} rt=%{DATA:rt} src=%{IP:src} smac=%{MAC:smac} cat=%{GREEDYDATA:cat} act=%{GREEDYDATA:act} reason=%{GREEDYDATA:reason} outcome=%{DATA:outcome} CSMTRPatternDisposition=%{GREEDYDATA:CSMTRPatternDisposition} . . . → Read More: CrowdStrike SIEM Connector Grok Rules

Automating Setting up Tenable.io AWS Connector Role

Steve Stonebraker posted this in AWS on October 2nd, 2019

I recently had to set up quite a few AWS Connectors in Tenable.io for various AWS accounts.

This can become quite a cumbersome task so I decided to automate it.

Prerequisites ~/.aws/config with multiple profiles trustpolicy.json (shown below) trustpolicy.json

This will be used by our script for the initial role creation. The account # referenced . . . → Read More: Automating Setting up Tenable.io AWS Connector Role

Bulk Lookup Owner of IP Address

Steve Stonebraker posted this in bash on September 18th, 2019

To perform a bulk whois lookup of a list of IP addresses use the following script:

Bulk whois lookup while read ip; do if [ ! -z “$ip” ]; then echo -n “$ip – ” && whois $ip 2>/dev/null grep “Organization” -m 1; fi; done < ip_list.txt Example input (ip_list.txt) 172.217.8.206 172.217.8.203 172.217.8.266 151.101.65.67 Output . . . → Read More: Bulk Lookup Owner of IP Address

List All Subnets Across Multiple AWS accounts/profiles

Steve Stonebraker posted this in AWS on September 10th, 2019

Recently I needed to generate a list of all subnets across every AWS account in an organization.

I’ve documented an easy way to achieve this

Prerequisites

Set up your aws config for multiple profiles (one for each account)

[default] region=us-east-1 output=json [profile account1] role_arn = arn:aws:iam::XXXXXXXXXXXX:role/OrganizationAccountAccessRole source_profile = default region=us-east-1 output=json [profile account2] role_arn = . . . → Read More: List All Subnets Across Multiple AWS accounts/profiles

Limiting S3 Sync Bandwidth

Steve Stonebraker posted this in AWS on September 10th, 2019

Out of the box the aws s3 application is suppose to limit bandwidth by setting the “s3.max_bandwidth” option.

Example:

aws configure set default.s3.max_bandwidth 5MB/s Problem

aws s3 sync is using more bandwidth than the ~/.aws/config file has specified.

Replication Steps

Run the following command to set a max bandwidth limit for the s3 application

aws . . . → Read More: Limiting S3 Sync Bandwidth

Testing Amazon S3 Bucket for Public Write Permissions

Steve Stonebraker posted this in AWS on September 9th, 2019

Recently I needed to confirm if an s3 bucket was indeed publicly writable (by trying to write to it from a different account). I decided to document how to confirm this for your organization.

Prerequisites AWS CLI installed Two AWS accounts Account A – Has a bucket you suspect may be publicly writable Account B . . . → Read More: Testing Amazon S3 Bucket for Public Write Permissions

Install Telnet Client from Command Prompt Windows 10

Steve Stonebraker posted this in Windows on August 20th, 2019

This post covers how to install the telnet client from the command prompt on Windows 10.

Run the following command:

pkgmgr /iu:”TelnetClient”

Jenkins Cleanup Old Builds

Steve Stonebraker posted this in Other on August 5th, 2019

I wrote a quick shell script to cleanup old Jenkins builds. This will delete any build older than 30 days.

#!/bin/bash # jenkins_delete_old_builds.sh # Author: Steve Stonebraker # Date: 8/5/2019 # Description: Deletes any build older than 30 days # Place in crontab # @daily /bin/bash -x /root/scripts/jenkins_cleanup.sh > /root/scripts/jenkins_cleanup.log find /var/lib/jenkins/jobs/*/builds/ -maxdepth 1 -mindepth . . . → Read More: Jenkins Cleanup Old Builds

Detecting Windows Lateral Movement

Steve Stonebraker posted this in Windows on July 31st, 2019

I came across a great article on detecting windows lateral movement and wanted to share it with everyone:

CERT-EU Security Whitepaper 17-002

“Detecting Lateral Movements in Windows Infrastructure”

https://cert.europa.eu/static/WhitePapers/CERT-EU_SWP_17-002_Lateral_Movements.pdf

Install Chrome using PowerShell

Steve Stonebraker posted this in powershell, Windows on July 30th, 2019

To install Google Chrome using Powershell (headless install) run the following command from and Administrative PowerShell Prompt:

$LocalTempDir = $env:TEMP; $ChromeInstaller = “ChromeInstaller.exe”; (new-object System.Net.WebClient).DownloadFile(‘http://dl.google.com/chrome/install/375.126/chrome_installer.exe’, “$LocalTempDir\$ChromeInstaller”); & “$LocalTempDir\$ChromeInstaller” /silent /install; $Process2Monitor = “ChromeInstaller”; Do { $ProcessesFound = Get-Process | ?{$Process2Monitor -contains $_.Name} | Select-Object -ExpandProperty Name; If ($ProcessesFound) { “Still running: $($ProcessesFound -join ‘, ‘)” . . . → Read More: Install Chrome using PowerShell

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