How CRED Eliminated Critical Security Vulnerabilities and Strengthened AWS Infrastructure with IMDSv2 Migration

The fintech industry operates under constant threat from sophisticated cyberattacks, where a single security vulnerability can lead to devastating data breaches, regulatory penalties, and irreparable damage to customer trust. When CRED's engineering team discovered their AWS infrastructure was exposed to Server-Side Request Forgery (SSRF) attacks through outdated Instance Metadata Service configurations, they faced a critical decision that would impact the security of their entire multi-product platform.

What followed was a comprehensive security transformation that not only eliminated major attack vectors but also established a gold standard for cloud infrastructure security. According to the CRED engineering team, their systematic migration to AWS IMDSv2 across all compute workloads resulted in a dramatic reduction of their security blast radius and protection against multiple attack vectors that had previously threatened their customer data and financial operations.

The challenge wasn't just technical, `it required coordinating changes across hundreds of microservices running on AWS ECS, EC2 instances, and EKS clusters without causing any service disruptions. The stakes were particularly high for a fintech platform where even brief downtime could impact thousands of credit card transactions and user financial activities.

The Hidden Vulnerability Threatening Modern Cloud Workloads

CRED's infrastructure exemplifies the complexity of modern fintech platforms. Their multi-product ecosystem relies on numerous microservices predominantly running on AWS ECS (Elastic Container Service), with additional EC2 instances and EKS clusters handling workloads requiring enhanced resource management capabilities. While this distributed architecture enables scalability and flexibility, it also creates numerous potential attack surfaces.

The critical vulnerability centered around AWS's Instance Metadata Service (IMDS), a service available at the IP address 169.254.169.254 that provides EC2 instances with metadata about themselves. This includes seemingly innocuous information like instance IDs and IP addresses, but more critically, it provides access to IAM credentials through the EC2 Instance Profile Role.

According to the CRED team's analysis, their existing IMDSv1 configuration created a perfect storm for SSRF attacks. If any application running on their EC2 instances became vulnerable to SSRF attacks, malicious actors could potentially exfiltrate IAM credentials directly from the metadata endpoint. These stolen credentials could then be used to escalate privileges and gain unauthorized access to sensitive AWS resources including S3 buckets containing customer data, databases with financial information, or even launch further attacks within their environment.

The business implications were staggering. In the fintech sector, a successful breach could result in millions of dollars in regulatory fines, customer compensation, and long-term reputation damage. For CRED, which handles sensitive financial data and credit card information for thousands of users, the risk was simply unacceptable.

The Strategic Decision to Modernize Security Infrastructure

The CRED engineering team recognized that addressing this vulnerability required more than a simple patch, it demanded a fundamental shift in how their infrastructure handled metadata requests. After extensive research and risk assessment, they decided to migrate their entire AWS compute infrastructure to IMDSv2, AWS's enhanced version of the Instance Metadata Service.

IMDSv2 introduces a session-based authentication mechanism that requires applications to first obtain a token before accessing metadata. This seemingly small change creates multiple layers of protection: the token cannot be retrieved once generated, only works within the instance where it was created, and automatically expires after a set period.

The decision wasn't taken lightly. The team evaluated several approaches, including implementing custom security controls, using third-party solutions, or accepting the risk with additional monitoring. However, the comprehensive protection offered by IMDSv2, combined with AWS's native support and SDK integration, made it the clear choice for their security-first culture.

The strategic value extended beyond immediate threat mitigation. By standardizing on IMDSv2, CRED would position themselves ahead of industry security trends and demonstrate to customers, investors, and regulatory bodies their commitment to maintaining cutting-edge security practices.

Engineering a Zero-Disruption Security Transformation

The CRED team developed a sophisticated 5-phase migration strategy designed to eliminate security vulnerabilities while maintaining 100% service availability. Their approach demonstrates how complex infrastructure changes can be executed without impacting business operations.

Phase 1: Planning & Strategizing

The team began with comprehensive strategic planning to define clear objectives and success metrics. They established governance structures, identified stakeholder dependencies, and created a detailed roadmap for the entire migration. This foundational phase ensured alignment across teams and reduced execution risks.

Key activities included risk assessment workshops, dependency mapping across services, and establishing rollback procedures. By investing time upfront, they prevented costly mid-migration corrections.

Phase 2: Gaining Visibility

Complete visibility into the current infrastructure was critical. The team used AWS CloudWatch's Metadata NoToken metric to identify exactly which services were actively using the vulnerable endpoint. This data-driven approach enabled them to prioritize migration efforts and identify potential disruption points before they became problems.

They discovered that their infrastructure spanned multiple AWS services across three vulnerable categories: standard EC2-based services, non-EC2 services like SageMaker, and EC2-based services with special configuration requirements like Auto Scaling Groups and Launch Templates.

Phase 3: Defining Scope & Coverage

With complete visibility established, the team carefully defined migration scope and prioritized which services to address first. One significant challenge emerged with containerized workloads, Docker containers running on ECS with EC2 networking couldn't access the vulnerable endpoint due to default Response Hop Limit configurations.

The solution required updating the hop limit configuration from 1 to 2, allowing metadata responses to properly traverse the container networking layer. This finding led to comprehensive testing protocols for all container-based services before full deployment.

Phase 4: Remediating Caveats

During testing, the team identified several third-party integrations that didn't yet support IMDSv2. Rather than delaying the migration, they proactively upgraded to vendor versions with IMDSv2 support, coordinating with software providers to ensure compatibility across their entire technology stack.

This phase highlighted the importance of vendor management in security transformations. The team established new procurement criteria requiring IMDSv2 support for all future third-party integrations, embedding security requirements into their vendor selection process.

Phase 5: Post-Migration Controls

After successful migration, the team implemented comprehensive monitoring and governance controls to prevent regression. They established automated checks to ensure IMDSv2 remained enforced across all services and created alerts for any configuration drift.

Post-migration controls included policy enforcement through infrastructure-as-code, continuous compliance monitoring, and regular security audits. This final phase transformed the migration from a one-time project into a sustained security posture.

Implementation Results: Quantifiable Security Improvements

The CRED team's systematic approach delivered impressive results across multiple security and operational metrics. Their migration eliminated critical vulnerabilities while establishing a more robust security foundation for future growth.

The most significant achievement was the complete elimination of SSRF attack vectors targeting their metadata services. By requiring token-based authentication for all metadata requests, they effectively closed a vulnerability that had exposed their entire AWS infrastructure to potential credential theft and privilege escalation attacks.

Key Security Outcomes:

• 100% protection against SSRF attacks targeting metadata services
• Complete elimination of unauthorized IAM credential access through metadata endpoints
• Dramatic reduction in potential blast radius from infrastructure compromises
• Enhanced protection against attacks targeting web application firewalls, Layer 3 firewalls, and reverse proxies
• Proactive defense against both current and emerging attack patterns targeting cloud metadata services

The migration also delivered operational benefits that strengthened their overall infrastructure management. By standardizing on IMDSv2 across all compute workloads, they simplified security monitoring, reduced the complexity of compliance auditing, and established consistent security baselines across development, staging, and production environments.

Perhaps most importantly, the team established preventive controls using AWS Service Control Policies (SCPs) that automatically prevent the creation of any new resources without IMDSv2 configuration. This ensures their security improvements remain permanent and can't be accidentally reversed by future deployments.

Scaling Security Excellence Across Complex Infrastructures

The CRED migration offers valuable insights for organizations managing large-scale cloud infrastructures. Their experience demonstrates that comprehensive security transformations are achievable without service disruptions when approached systematically.

Critical Success Factors:

• Phased rollout strategy that prioritizes low-risk environments for initial testing
• Comprehensive dependency mapping to identify all affected services and integrations
• Proactive container networking configuration to prevent service disruptions
• Vendor coordination to ensure third-party software compatibility
• Automated preventive controls to maintain security standards long-term

The team's development of custom tooling for migration management proved particularly valuable. Rather than manually updating hundreds of resources across multiple AWS accounts, they created automation that handled the complexity while providing detailed reporting and rollback capabilities.

Their emphasis on post-migration controls through SCPs demonstrates advanced cloud governance thinking. By preventing the creation of non-compliant resources at the policy level, they ensured their security improvements would persist despite organizational changes, staff turnover, or rapid scaling requirements.

For organizations considering similar migrations, the CRED approach highlights the importance of treating security improvements as comprehensive infrastructure transformations rather than simple configuration changes. Their success stemmed from understanding both the technical requirements and the business implications of their security decisions.

Future-Proofing Cloud Security in the Fintech Era

CRED's IMDSv2 migration represents more than a tactical security improvement it demonstrates a strategic approach to infrastructure security that positions fintech companies for long-term success. As cloud-native applications become increasingly complex and regulatory requirements continue evolving, organizations need security practices that can adapt and scale.

The team's experience offers a roadmap for other fintech companies facing similar challenges. By prioritizing comprehensive security transformations over incremental patches, organizations can build infrastructure that not only addresses current threats but provides a foundation for future security requirements.

Looking ahead, the principles demonstrated in CRED's migration, systematic risk assessment, zero-disruption implementation, comprehensive testing, and automated governance will become increasingly valuable as cloud infrastructures grow more complex and security threats continue evolving.

For engineering teams managing critical financial infrastructure, the CRED approach proves that ambitious security improvements are achievable without compromising operational stability or customer experience. Their success reinforces the value of investing in comprehensive security transformations that deliver both immediate protection and long-term strategic advantages.