Testing the new AWS Security Agent

This article isCyberAgent Group SRE Advent Calendar 2025This is the 12th article.
 
 
This article isCyberAgent Group SRE Advent Calendar 2025This is the article for the 12th day.

Introduction


My name is Taninari, and I work in the Service Reliability Group (SRG) of the Media Headquarters.
#SRG(Service Reliability Group) is a group that mainly provides cross-sectional support for the infrastructure of our media services, improving existing services, launching new ones, and contributing to OSS.
 
This article is based on the "AWS Security AgentThis article aims to provide information for decision-makers considering the introduction and utilization of new services by actually testing "AI-based design review" and clarifying the effectiveness of AI-based design review and the challenges of dynamic testing.
 
At re:Invent 2025 in December 2025, AWS announced "AWS Security Agent," a new security service that leverages generative AI. While previous security tools have focused on matching known patterns and rule-based detection, this new service stands out in that it uses AI to understand the context of the application. Its appeal lies in its end-to-end support throughout the development lifecycle, from design to implementation and ongoing testing, but what about its actual usability and accuracy? In this article, we report on the results of testing the preview version of AWS Security Agent using "VulnBank," a vulnerability app we created for educational purposes.
I plan to divide this article into two parts. In the first part, I will introduce the overview of AWS Security Agent and how to set up AWS Security Agent. In the next part, I will summarize by explaining how each feature works.
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AWS Security Agent is currently in preview and available only in US East (N. Virginia) as of December 2025.

AWS Security Agent Overview and Features


AWS Security Agent is a service that uses AI to analyze application blueprints, source code, and operating environments to detect security risks and propose remediation measures. Its greatest feature is that it goes beyond simply detecting code defects by reading documents such as architecture diagrams and requirements specifications to understand the intent of the entire system before assessing risks. Traditional static analysis (SAST) and dynamic analysis (DAST) tools have issues with high false positives and overlooking vulnerabilities caused by business logic. AWS Security Agent aims to perform security reviews from a perspective closer to, or even better than, that of a human, by using generative AI to interpret what data the app handles and what flow it follows. This service consists of the following three main functions.

1. Design Review

During the design stage before implementation, we upload architecture diagrams and specifications (Markdown or PDF) and identify security risks in the design. We point out deficiencies in authentication and authorization, as well as data handling issues, based on standards such as the AWS Well-Architected Framework and OWASP Top 10.

2. Code Security Review

It works with repositories such as GitHub and analyzes code when a pull request is created. It detects SQL injections, hard-coded secrets, and more, not just by looking at the difference in changes, but also by taking into account information from the entire repository and related design documents. Another major feature is that it doesn't just point out issues, but also suggests the code to be fixed.

3. Penetration Testing

An AI agent performs simulated attacks on live web applications to verify vulnerabilities. It can also test private resources within a VPC, and if a vulnerability is discovered, it will provide reproduction steps and suggested fixes.
 

Verification: Diagnosis using the self-made app VulnBank


This time, I created a web application called "VulnBank" using Go that intentionally contains vulnerabilities. The application intentionally contains the following vulnerabilities:
  • SQL injection(Multiple places) - Query construction by string concatenation
  • IDOR(Insecure Direct Object Reference)- Lack of authorization checks
  • Broken Access Control- Unauthorized access to administrator functions
  • Hard-coded secrets- JWT private key, administrator password, etc.
  • Weak password policies- Lack of password validation
  • /debug/*
  • Mass Assignment- Set any field from the request
 

Setting up AWS Security Agent


We will set up the AWS Security Agent to use it.
First, create an agent space. All you need to create is a name and description.
 
Once creation is complete, it will look like this:
Penetration testing

Configuring Code Review

We will configure each one individually.
Enable code review
Install and authorize
 
Install & Authorize
enable code review
Pentest remediation enabled
Code review

Penetration Test Settings

 
ペネトレーションテストをセットアップ
This time, I wanted to deploy the application to EC2 and test it on the EC2 application, so I verified it using the HTTP route.
💡
As I will explain later, this method ultimately resulted in a failed status and did not work.
 
到達不能
検証トークン
失敗
In this state of failure
  • Change port from 8080 to 80
  • Change port from 80 to 443 (self-signed certificate)
  • Assign a domain and try accessing via the domain
  • Create a certificate with ACM and change access to via ALB
失敗
DNS テキストレコード
 
検証済み
 
Once the above settings are complete, you can confirm that all functions are now available.
 

Summary of this article


In this blog, we introduced AWS Security Agent and how to set it up.
失敗
Next time, I'll write a blog post summarizing the code reviews and penetration tests I actually performed.
 
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