AWS Security Investigation Challenge: Master Cloud Incident Response, IAM Analysis, and Splunk Log Forensics + Video

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Introduction:

Cloud security incidents are no longer a matter of if but when. As organizations rapidly migrate to AWS, the attack surface expands exponentially, making hands-on investigation skills critical for every security professional. The recent AWS Security Investigation Challenge—a three-hour marathon of IAM analysis, Splunk log forensics, and incident response—demonstrated exactly what it takes to secure cloud environments under pressure. This article breaks down the core competencies tested in the challenge, providing you with actionable commands, detection queries, and step-by-step investigation workflows to level up your cloud security game.

Learning Objectives:

  • Master AWS CloudTrail log analysis to detect and investigate suspicious IAM activity
  • Build and execute Splunk queries for real-time threat hunting and incident response
  • Implement least-privilege IAM policies and automate security auditing with Scout Suite
  • Develop a structured incident response playbook for compromised AWS credentials
  • Harden AWS environments against privilege escalation and data exfiltration attacks

You Should Know:

  1. AWS CloudTrail and IAM Analysis: The Foundation of Cloud Investigations

Every AWS security investigation begins with CloudTrail—the service that records every API call made within your environment. When an incident occurs, your first step is to establish a timeline of who did what, when, and from where.

Step‑by‑step guide to investigating IAM activity:

  1. Enable CloudTrail in all regions and configure it to deliver logs to an S3 bucket and CloudWatch Logs for real-time monitoring.

  2. Ingest CloudTrail logs into Splunk using the Splunk Add-on for AWS. This allows you to search, correlate, and visualize security events at scale.

  3. Identify all IAM users and roles that interacted with your AWS services during the suspicious timeframe. A basic Splunk query to list all IAM activity:

index=aws_cloudtrail eventSource=iam.amazonaws.com
| stats count by userIdentity.userName, eventName, sourceIPAddress
| sort - count
  1. Look for privilege escalation attempts—events where a user creates access keys for another user, modifies policy versions, or attaches administrative policies. Key events to monitor:
    – `CreateAccessKey` – potential backdoor creation
    – `CreatePolicyVersion` with `”Effect”:”Allow”` and `””` in resources
    – `SetDefaultPolicyVersion` – rolling back to a permissive version
    – `AttachUserPolicy` or `AttachRolePolicy` with admin privileges

  2. Correlate IAM changes with other AWS services—check for Lambda function updates, EC2 instance launches, or S3 bucket policy modifications that may indicate lateral movement.

Linux Command to fetch CloudTrail logs via AWS CLI:

 List CloudTrail events for a specific user in a time range
aws cloudtrail lookup-events \
--lookup-attributes AttributeKey=Username,AttributeValue=malicious-user \
--start-time "2026-06-28T00:00:00Z" \
--end-time "2026-06-29T23:59:59Z" \
--max-results 50

Windows PowerShell equivalent:

 Using AWS Tools for PowerShell
Get-CTEvent -LookupAttribute @{AttributeKey="Username"; AttributeValue="malicious-user"} `
-StartTime "2026-06-28T00:00:00Z" `
-EndTime "2026-06-29T23:59:59Z" `
-MaxResults 50
  1. Splunk Log Analysis: Building Detection Queries That Work

Splunk is the workhorse of modern Security Operations Centers (SOCs). During the challenge, participants analyzed hundreds of thousands of log entries to pinpoint malicious activity. The key is knowing which queries to run and how to interpret the results.

Step‑by‑step guide to Splunk-based threat hunting:

  1. Detect excessive AccessDenied events—a classic sign of brute-force or reconnaissance:
index=aws_cloudtrail errorCode=AccessDenied
| stats count by userIdentity.userName, sourceIPAddress, eventName
| where count > 10
| table userIdentity.userName, sourceIPAddress, eventName, count

This query surfaces IAM users or IPs generating more than 10 AccessDenied errors, indicating either misconfigured permissions or active scanning.

  1. Identify unauthorized AMI sharing—attackers often share machine images with external accounts to exfiltrate data:
index=aws_cloudtrail eventName=ModifyImageAttribute
| where requestParameters.attributeType="launchPermission"
| table userIdentity.userName, sourceIPAddress, requestParameters.imageId, requestParameters.add

Monitoring this activity can prevent data exfiltration via shared AMIs.

3. Track policy changes that grant wildcard permissions:

index=aws_cloudtrail eventName=CreatePolicyVersion
| spath input=requestParameters.policyDocument
| where like(policyDocument, "%\"Resource\": \"\"%")
| table userIdentity.userName, sourceIPAddress, eventTime, requestParameters.policyName

This detects the creation of overly permissive policies—a common privilege escalation vector.

  1. Build a dashboard for real-time monitoring of high-risk IAM events:
index=aws_cloudtrail (eventName=CreateAccessKey OR eventName=CreatePolicyVersion OR eventName=AttachUserPolicy)
| timechart count by eventName span=1h
  1. Investigate the “who” and “why” —always correlate IAM activity with the user’s historical behavior. Use `| stats` to build a baseline and flag anomalies.

3. Incident Response Playbook for Compromised AWS Credentials

When credentials are compromised, every second counts. A structured playbook ensures you don’t miss critical steps.

Step‑by‑step incident response workflow:

  1. Detection: Monitor AWS GuardDuty findings, AWS Security Hub alerts, and CloudTrail for anomalous API calls. Set up CloudWatch Events to trigger automated responses for high-severity alerts.

2. Containment:

  • Immediately deactivate the compromised IAM user or role: `aws iam delete-login-profile –user-1ame compromised-user`
    – Delete or deactivate all access keys for that user: `aws iam update-access-key –access-key-id AKIA… –status Inactive`
    – Restrict inbound/outbound traffic using Security Groups and Network ACLs

3. Investigation:

  • Pull all CloudTrail logs for the compromised user over the past 30 days
  • Identify all resources accessed, modified, or created
  • Check for persistent backdoors—new roles, Lambda functions, or EC2 instances
  • Use IAM Access Advisor to review the user’s last accessed services

4. Eradication:

  • Remove any unauthorized IAM policies, roles, or resources
  • Rotate all credentials for accounts that interacted with the compromised user
  • Apply least-privilege policies across the entire environment

5. Recovery and Lessons Learned:

  • Restore affected resources from clean backups
  • Conduct a post-incident review to identify gaps in monitoring or response
  • Update detection rules and runbooks based on the attack vector

Linux Command to list and deactivate access keys:

 List all access keys for a user
aws iam list-access-keys --user-1ame compromised-user

Deactivate a specific key
aws iam update-access-key --access-key-id AKIA... --status Inactive --user-1ame compromised-user

Delete the key permanently (only after investigation)
aws iam delete-access-key --access-key-id AKIA... --user-1ame compromised-user

4. Automated Security Auditing with Scout Suite

Proactive security auditing is essential to catch misconfigurations before attackers exploit them. Scout Suite is an open-source tool that scans AWS, Azure, and GCP environments for security gaps and generates comprehensive HTML reports.

Step‑by‑step guide to running Scout Suite:

  1. Install Scout Suite on a Linux instance (Ubuntu recommended):
 Install Python dependencies
sudo apt update && sudo apt install python3-pip -y

Clone the repository
git clone https://github.com/nccgroup/ScoutSuite.git
cd ScoutSuite

Install Scout Suite
pip install -r requirements.txt
python setup.py install
  1. Configure AWS credentials with read-only permissions. Create an IAM policy that allows Describe, Get, and `List` actions across all services. Attach this policy to a dedicated IAM user.

  2. Run a security audit against your AWS account:

 Basic audit
scout aws --report-dir ./reports

Audit a specific profile
scout aws --profile my-profile --report-dir ./reports

Include specific services
scout aws --services s3,iam,ec2 --report-dir ./reports
  1. Review the HTML report—it categorizes findings by severity (HIGH, MEDIUM, LOW) and provides remediation guidance for each issue. Focus on HIGH-risk findings first:

– Unrestricted S3 bucket policies
– IAM users with administrative access
– Security groups with open ports (0.0.0.0/0)
– Unused IAM keys older than 90 days

  1. Automate regular scans using a CI/CD pipeline or scheduled Lambda function to ensure continuous compliance.

Windows Command (using Python on Windows):

 Install Scout Suite via pip
pip install scoutsuite

Run audit (ensure AWS credentials are configured via environment variables)
scout aws --report-dir ./reports

5. Hardening IAM: Least-Privilege in Practice

The principle of least privilege is the cornerstone of AWS security. During the challenge, teams that had pre-audited their IAM policies had a significant advantage.

Step‑by‑step guide to IAM hardening:

  1. Use IAM Access Analyzer to identify unused permissions and overly permissive roles. Generate findings for policies that grant access to resources outside your organization.

2. Implement conditional access using IAM policy conditions:

  • Restrict access based on IP address: `”Condition”: {“IpAddress”: {“aws:SourceIp”: “203.0.113.0/24″}}`
    – Enforce MFA for sensitive actions: `”Condition”: {“Bool”: {“aws:MultiFactorAuthPresent”: “true”}}`
    – Limit access by time of day: `”Condition”: {“DateLessThan”: {“aws:CurrentTime”: “2026-12-31T23:59:59Z”}}`
  1. Rotate access keys regularly—set a maximum age of 90 days. Use AWS Config rules to automatically flag and deactivate old keys.

  2. Enable CloudTrail log file validation to ensure logs haven’t been tampered with:

aws cloudtrail update-trail --1ame my-trail --enable-log-file-validation

5. Conduct regular IAM credential reports:

 Generate a credential report
aws iam generate-credential-report

Download the report
aws iam get-credential-report --output text --query Content > credential_report.csv

Analyze the report for:

  • Users with no MFA device
  • Access keys older than 90 days
  • Password last changed beyond policy limits

6. Lambda Function Security: Detecting Code Tampering

Attackers often modify Lambda functions to establish persistence or exfiltrate data. Detecting unauthorized `UpdateFunctionCode` events is critical.

Step‑by‑step guide to Lambda security monitoring:

  1. Monitor CloudTrail for `UpdateFunctionCode` events—this API call indicates a Lambda function’s code has been changed:
index=aws_cloudtrail eventName=UpdateFunctionCode
| table _time, userIdentity.userName, sourceIPAddress, requestParameters.functionName, requestParameters.s3Key
| sort - _time
  1. Set up CloudWatch Events to trigger an SNS alert whenever a Lambda function is updated outside of a deployment pipeline.

  2. Enable Lambda versioning and aliases—this allows you to quickly roll back to a known-good version if malicious code is detected.

  3. Restrict who can update Lambda functions using IAM policies that limit `lambda:UpdateFunctionCode` to specific roles or deployment users.

  4. Audit Lambda execution roles—ensure they follow least-privilege and do not grant over-permissive access to other AWS services.

  5. Building a Cloud Security Home Lab for Continuous Learning

The best way to master these skills is through hands-on practice. HAXCAMP offers 100+ Blue Team labs that simulate real-world cloud security scenarios.

Step‑by‑step guide to setting up your own cloud security lab:

  1. Create a dedicated AWS account for learning purposes (use AWS Organizations to isolate it from production).

  2. Deploy a vulnerable environment intentionally—create misconfigured S3 buckets, overly permissive IAM roles, and open security groups to practice detection and remediation.

  3. Install and configure Splunk (or Splunk Free) on an EC2 instance to ingest CloudTrail logs and practice building detection queries.

  4. Run Scout Suite and Prowler regularly to identify misconfigurations and track your progress in hardening the environment.

  5. Participate in hands-on challenges—platforms like HAXCAMP provide structured labs that guide you through investigation workflows, from initial alert to root cause analysis.

What Undercode Say:

  • Hands-on experience beats theory every time—the three-hour challenge proved that participants who had previously practiced with CloudTrail and Splunk queries were able to identify and contain incidents significantly faster.
  • IAM is the new perimeter—in the cloud, identity is the primary control plane. Mastering IAM analysis, policy auditing, and privilege escalation detection is non-1egotiable for modern security professionals.
  • Automation is your ally—tools like Scout Suite, AWS Config, and automated Splunk dashboards reduce manual effort and ensure you don’t miss critical alerts during high-pressure incidents.
  • Incident response is a team sport—the challenge emphasized collaboration, with participants sharing findings and correlating evidence across multiple data sources to build a complete attack timeline.
  • Continuous learning is essential—the cloud threat landscape evolves rapidly. Engaging in regular hands-on challenges, lab exercises, and CTF-style competitions keeps your skills sharp and your detection playbooks current.

Prediction:

  • +1 Cloud security challenges and hands-on labs will become a standard part of security certification programs, bridging the gap between theoretical knowledge and practical incident response skills.
  • +1 AI-powered SIEM tools will increasingly automate log analysis, but human analysts will remain essential for contextualizing alerts and making judgment calls during complex investigations.
  • -1 As AWS adoption accelerates, the shortage of cloud-security-skilled professionals will worsen, driving up demand (and salaries) for those who can demonstrate practical investigation capabilities.
  • +1 Open-source tools like Scout Suite and Prowler will gain wider enterprise adoption as organizations seek cost-effective ways to continuously audit their cloud postures.
  • -1 Attackers are already shifting their tactics to target IAM and identity providers—expect a rise in credential theft, privilege escalation, and supply chain attacks against cloud environments in the coming year.

▶️ Related Video (80% Match):

https://www.youtube.com/watch?v=2tzJVCvq4mg

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