How to Protect Your AWS Server From Hackers: An Expert Guide

Step 1: Signs Your Server Has Been Hacked

Sometimes it’s obvious—your website goes down, strange popups appear, or files start downloading without your permission. Other times, it’s subtle—like spam emails being sent from your server or AWS sending you an abuse complaint.

Here are some common red flags:

• Your hosting provider notifies you about abuse activity.
• Unknown files (e.g., suspicious PHP scripts) appear in your directories.
• Sudden spikes in outgoing emails (spam emitters).
• Users report strange downloads (e.g., APKs auto-downloading from your site).
• CPU/memory usage skyrockets without reason.
• Security tools or firewalls alert you to anomalies.

There are also powerful third-party tools that help you detect, investigate, and analyse breaches, showing you who hacked, what they hacked, and how deep it goes.

So grab your coffee … we’re diving into a real-world case study.

Case Study: A Hacked Client Website

A client’s website was running smoothly. until one day it wasn’t.

Hackers compromised the site in such a way that:

1. Visitors who accessed the website automatically downloaded a malicious APK file.
2. The hosting provider flagged the server because it was sending thousands of spam emails per day via SMTP

Upon investigation, we found:

• A suspicious mail file in the Postfix directory (36043117DA7) is sending mass spam.

• The php.info file was replaced with a malicious script that triggered APK downloads.

Lesson? Hackers don’t just crash your site. They weaponise it for spamming, malware distribution, crypto mining, and much more.

Why Did the Hack Happen?

Security gaps. Period. Some of the most common reasons include:

• • Improper Security Group (SG) configuration – open ports everywhere.
  • No Web Application Firewall (WAF) – nothing filtering bad traffic.
  • No file integrity monitoring – no alerts when critical files are altered.
  • Poor patch management – outdated OS, CMS, or plugins.
  • Lack of monitoring – missing alerts on traffic spikes or suspicious logs.
    

If you’re not proactively watching these areas, you’re basically leaving the front door open for attackers.

Step 2: What to Do When Your Server Gets Hacked

1. Don’t ignore provider alerts.
   • AWS, Google Cloud, and others will immediately notify you if abuse originates from your server. Take it seriously.
2. Check for spam emitters.
   • Look inside Postfix/Sendmail queues for suspicious files/scripts sending spam.
3. Audit compromised files.
   • Compare suspicious files (like php.info) with clean backups.
4. Scan with malware/security tools.
   • Use tools like ClamAV, Lynis, or commercial security scanners.
5. Patch and clean.
   • Update all software, plugins, and system packages.
   • Remove or quarantine infected files.
6. Reset credentials.
   • Rotate passwords, SSH keys, API keys, and database credentials.
7. Harden security.
   • Close unnecessary ports, enforce firewall rules, enable 2FA, and set up monitoring.
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Understanding AWS Abuse Reports

If you’re on AWS and your server is compromised, you’ll likely get an abuse report.

• Who raises it?
  • Affected clients, third-party watchdogs, or AWS itself.
• What does it mean?
  • Your resources are being used for malicious purposes (spam, malware hosting, DDoS, etc.).
• Why it matters:
  • If you don’t act, AWS can suspend or even terminate your account under its Acceptable Use Policy.

If you suspect abuse, AWS provides a dedicated EC2 abuse report form for investigation.

Step 3: How to Protect Your Server from Future Hacks

Now for the part you’ve been waiting for—prevention.

AWS and other cloud platforms offer powerful services to help protect your infrastructure. Some must-haves:

• AWS Inspector – scans your environment for vulnerabilities.
• AWS Config – tracks changes in configuration and security.
• AWS GuardDuty – detects malicious or unauthorised activity.
• AWS Trusted Advisor – gives best-practice recommendations.
• AWS Detective – helps investigate suspicious activity.
• AWS Macie – protects sensitive data.
• AWS WAF (Web Application Firewall) – blocks malicious requests.
• AWS Security Hub – centralises all security alerts.