Configure cross-account access from an EC2 Instance to an AWS CodeCommit repo using roles

You can configure access to CodeCommit repositories for IAM Role attached to an EC2 Instance in another AWS account. This is often referred to as cross-account access. This section provides an example and instructions for configuring cross-account access for a repo named SharedDemoRepo in the US East (Ohio) Region in an AWS account (referred to as AccountA) to an IAM Role/Instance Profile attached to an EC2 Instance in another AWS account (referred to as AccountB)....

September 1, 2022 · 3 min · Harwinder Sandhu

Investigating CloudTrail Logs using ELK Stack

AWS CloudTrail is an AWS service that helps you enable governance, compliance, and operational and risk auditing of your AWS account. Actions taken by a user, role, or an AWS service are recorded as events in CloudTrail. Events include actions taken in the AWS Management Console, AWS Command Line Interface, and AWS SDKs and APIs. You can ship these CloudTrail logs into the ELK stack and learn how to visualize these events, near real time, using Kibana....

April 20, 2021 · 3 min · Harwinder Sandhu

Splunk Attack Range on AWS - Guide

A quick guide to get Splunk Attack Range running on AWS. If you’re trying to run this locally, I would suggest having a look at this post Splunk Attack Range in a virtualized Ubuntu Guest VM. It’s a tool that allows you to create vulnerable instrumented local or cloud environments to simulate attacks against and collect the data into Splunk. I came across this Splunk post Detecting CVE-2020-1472 and was trying to replicate this in my own environment....

October 2, 2020 · 3 min · Harwinder Sandhu

dnscat2: Command and Control over the DNS

No matter how tightly you restrict outbound access from your network, you probably allow DNS protocol to at least one server. Adversaries can abuse this access in your firewall to establish stealthy Command and Control (C2) channels or to exfiltrate data that is difficult to block. To understand the use of DNS for C2 tunneling, let’s take a look at Ron Bowes’s tool dnscat2, which makes it relatively easy to experiment with such attack techniques....

August 15, 2020 · 5 min · Harwinder Sandhu

Detect Public S3 Bucket using Splunk

In today’s post, we will learn how to detect a public S3 bucket using Splunk. Later, we will see how we can respond to such incidents and even prevent them from happening in the first place. As you will see in the following examples, there are multiple ways to create an S3 bucket and make it public. Also, for this blog, I created some subdomains of logsec.cloud in Route53. Scenario 1: Using the AWS Web Console Create an S3 bucket and go to “Permissions” - “Access Control List” - “Public Access” - “Everyone” - Access to the objects -...

June 20, 2020 · 4 min · Harwinder Sandhu

Investigating S3 Scanning Activities on AWS

During the past week, we detected some suspicious activities across multiple AWS accounts in one of our clients’ environments. These activities seemed related to S3 bucket scanning by a bad actor. Here is one of the sample logs from the S3 access logs: 84fd7086179626a759fb59a0252a26d26dc1685e30f0ab922266b5abace8f998 <AWS-ACCOUNT-ID>-config-org-bucket [01/Jun/2020:13:27:34 +0000] 10.247.13.187 arn:aws:iam::799199334739:user/starling-ladyblackhawk-iad-prod 9WDX6MBZFQ6Z6RDR REST.HEAD.BUCKET - "HEAD / HTTP/1.1" 403 AccessDenied 243 - 9 - "-" "AWSConfig" - wFvPfIaSbdpcnNMdcTj+BNWn00r3OfqHV8sTt8gUXMzLA7O/MiWg+NPckix2TThK15V/p1JigVc= SigV4 ECDHE-RSA-AES128-SHA AuthHeader <AWS-ACCOUNT-ID>-config-org-bucket.s3.amazonaws.com TLSv1.2 The first thing that caught our attention in this log was the username starling-ladyblackhawk-iad-prod....

June 4, 2020 · 5 min · Harwinder Sandhu