Cloud Penetration Testing: AWS, Azure, and GCP Security Assessment

Why Cloud Penetration Testing Is Fundamentally Different

Cloud penetration testing is not simply traditional network penetration testing performed against infrastructure that happens to run in a data center you do not own. The cloud introduces entirely new attack surfaces, permission models, and exploitation techniques that require specialized knowledge and tooling. Organizations that apply conventional penetration testing methodologies to cloud environments consistently miss critical vulnerabilities that attackers actively exploit.

The shift from on-premises infrastructure to cloud-native architectures has been particularly dramatic across the San Francisco Bay Area, where startups and enterprises alike have embraced multi-cloud strategies to achieve scalability, resilience, and development velocity. However, the speed of cloud adoption has often outpaced the maturity of cloud security practices, creating a gap that adversaries are eager to exploit.

At CyberGuards, our cloud penetration testing practice has grown substantially as organizations recognize that their cloud environments require the same rigorous offensive security assessment that they have historically applied to on-premises networks — and often more, given the complexity of modern cloud architectures.

The Shared Responsibility Model: Where Security Gaps Hide

Every major cloud provider operates under a shared responsibility model, where the provider secures the underlying infrastructure and the customer is responsible for securing their configurations, data, and applications. Despite being a well-documented concept, the shared responsibility model remains one of the most misunderstood aspects of cloud security — and one of the most fertile sources of exploitable vulnerabilities.

Responsibility Boundaries by Service Type

The critical insight is that the boundaries are not always intuitive, and they shift depending on the specific service being consumed. A penetration test that focuses exclusively on the customer's responsibilities — while ignoring the integration points and trust boundaries between provider-managed and customer-managed components — will miss significant classes of vulnerabilities.

AWS Penetration Testing: Key Focus Areas

Amazon Web Services remains the dominant cloud platform by market share, and its extensive service catalog creates a correspondingly large attack surface. AWS penetration testing requires deep familiarity with the platform's identity model, networking constructs, and service-specific security configurations.

IAM Misconfigurations in AWS

AWS Identity and Access Management is simultaneously the platform's most powerful security control and its most common source of exploitable vulnerabilities. The flexibility of IAM policies — with their complex JSON syntax, multiple evaluation layers, and interaction between identity-based and resource-based policies — creates ample opportunity for misconfiguration.

Key IAM testing areas include:

• Overly Permissive Policies: IAM policies that grant * actions on * resources are disturbingly common, even in production environments. Our penetration testers enumerate all IAM policies, roles, and permission boundaries to identify excessive privileges that could enable privilege escalation.
• Cross-Account Role Assumptions: Organizations with multiple AWS accounts frequently configure cross-account roles for operational convenience. Misconfigured trust policies can allow unauthorized principals to assume roles in sensitive accounts, enabling lateral movement across the organization's entire AWS estate.
• Instance Metadata Service Exploitation: The EC2 Instance Metadata Service (IMDS) at 169.254.169.254 provides temporary security credentials to applications running on EC2 instances. Server-side request forgery (SSRF) vulnerabilities in web applications can be leveraged to retrieve these credentials, effectively compromising the IAM role attached to the instance. While IMDSv2 mitigates some of these risks, many organizations have not enforced its use across all instances.
• Access Key Exposure: Long-lived IAM access keys embedded in source code repositories, CI/CD pipelines, environment variables, and configuration files remain one of the most common initial access vectors in AWS compromises. Our testing includes thorough scanning for exposed credentials across all accessible systems.

S3 Bucket Exposure

Despite years of highly publicized data breaches involving misconfigured S3 buckets, storage exposure continues to be a pervasive issue. AWS has progressively tightened default S3 security settings, but legacy configurations, terraform state files with permissive ACLs, and misconfigured bucket policies still routinely expose sensitive data.

Our S3 testing methodology covers:

• Enumeration of all buckets across all regions associated with the target account
• Analysis of bucket policies, ACLs, and Block Public Access settings
• Identification of buckets accessible via predictable naming conventions
• Verification of encryption at rest configuration (SSE-S3, SSE-KMS, SSE-C)
• Review of bucket versioning and lifecycle policies for data recovery risks
• Assessment of cross-account access grants and pre-signed URL configurations

AWS Network Security Assessment

AWS networking introduces constructs that have no direct analog in traditional data center environments. Security groups, network ACLs, VPC peering connections, transit gateways, and PrivateLink endpoints all create potential pathways for unauthorized access if misconfigured.

Critical testing areas include security group rules that allow unrestricted inbound access on sensitive ports, VPC peering connections that expose internal services across account boundaries, and publicly accessible load balancers that bypass intended access controls. Bay Area organizations running complex multi-VPC architectures — common among the region's SaaS companies — are particularly susceptible to network segmentation failures that allow lateral movement between production, staging, and development environments.

Azure Penetration Testing: Key Focus Areas

Microsoft Azure presents a distinct set of security challenges, heavily influenced by its deep integration with Active Directory and the Microsoft 365 ecosystem. Azure penetration testing requires understanding both cloud-native identity concepts and the hybrid identity architectures that most enterprise Azure deployments employ.

Azure Active Directory and Entra ID

Azure Active Directory (now Microsoft Entra ID) is the identity backbone of virtually every Azure deployment, and its complexity creates numerous opportunities for exploitation:

• Application Registrations and Service Principals: Overprivileged application registrations with excessive API permissions are a common finding. Service principals with certificate or secret credentials that have not been rotated provide persistent access that survives password changes for the associated user accounts.
• Conditional Access Policy Gaps: Conditional Access policies are Azure's primary mechanism for context-aware access control. Missing or misconfigured policies — particularly those that fail to enforce MFA for privileged operations, allow legacy authentication protocols, or exclude service accounts — create exploitable gaps.
• Hybrid Identity Attack Paths: Organizations that synchronize on-premises Active Directory with Azure AD via Azure AD Connect create attack paths that span both environments. Compromise of the Azure AD Connect server or its associated service accounts can provide access to both the on-premises domain and the Azure tenant.
• Privileged Identity Management (PIM) Configuration: Azure PIM provides just-in-time elevation for privileged roles, but misconfigured PIM policies — including excessive activation durations, missing approval requirements, and overly broad eligible role assignments — can undermine its protective value.

Azure Storage and Data Exposure

Azure Blob Storage, Table Storage, Queue Storage, and File Shares each have independent access control mechanisms that can be misconfigured independently. Key testing areas include:

• Storage account access keys that provide unrestricted access to all data within the account
• Shared Access Signatures (SAS) with excessive permissions or expiration dates years in the future
• Blob containers with anonymous public access enabled
• Storage account firewall rules that allow access from overly broad IP ranges
• Managed disk snapshots shared across subscriptions without appropriate access controls

Azure Resource Manager Exploitation

Azure Resource Manager (ARM) controls the deployment and management of all Azure resources. Penetration testing of ARM focuses on role-based access control (RBAC) assignments, custom role definitions that grant excessive permissions, management group hierarchies that propagate privileges too broadly, and resource locks that may be missing on critical infrastructure components.

GCP Penetration Testing: Key Focus Areas

Google Cloud Platform has a smaller market share than AWS and Azure but is widely adopted by organizations in the San Francisco Bay Area — particularly among companies with deep ties to the Google ecosystem. GCP's security model has several unique characteristics that require specialized testing approaches.

GCP IAM and Organization Hierarchy

GCP's IAM model is built around a resource hierarchy — Organization, Folders, Projects, and Resources — where permissions are inherited downward. This inheritance model simplifies administration but can lead to overprivileged configurations when permissions are granted too high in the hierarchy.

• Primitive Roles: GCP's primitive roles (Owner, Editor, Viewer) grant extremely broad permissions that violate the principle of least privilege. Our testing identifies all principals assigned primitive roles and assesses the impact of these excessive permissions.
• Service Account Key Management: GCP service account keys are long-lived credentials that, when exported, function similarly to AWS access keys. Exposed service account keys provide persistent access to all resources the service account can access. Google recommends using Workload Identity Federation to avoid service account keys entirely, but many organizations have not completed this migration.
• Organization Policy Constraints: GCP's Organization Policy Service allows administrators to set guardrails across the organization hierarchy. Missing or misconfigured organization policies — such as those controlling external sharing, public IP assignment, and service account key creation — create risks that our penetration testers systematically evaluate.

GCP Storage and BigQuery Exposure

Google Cloud Storage buckets and BigQuery datasets are high-value targets in GCP environments. Testing focuses on:

• Bucket-level and object-level ACLs that grant access to allUsers or allAuthenticatedUsers
• Uniform bucket-level access configuration and its interaction with legacy ACLs
• BigQuery dataset permissions that expose sensitive analytical data to unauthorized principals
• Data transfer configurations that export data to less-secured destinations
• Pub/Sub topic and subscription permissions that could allow message interception or injection

GCP Networking and Compute

GCP's networking model, with its global VPC architecture and firewall rules applied at the network level rather than the instance level, creates unique testing considerations. Our assessment covers VPC firewall rules for overly permissive ingress and egress configurations, Cloud NAT configurations that could expose internal services, and GKE cluster configurations including RBAC, network policies, and node pool security settings.

Provider Rules of Engagement

Each cloud provider has specific policies governing penetration testing activities conducted against resources hosted on their platform. Understanding and complying with these policies is essential to avoid service disruptions, account suspensions, and potential legal complications.

Rules of Engagement Comparison

Cloud Penetration Testing Methodology

Effective cloud penetration testing follows a structured methodology that accounts for the unique characteristics of cloud environments while maintaining the rigor of traditional offensive security assessment.

Phase 1: Scoping and Authorization

Before any testing begins, we establish a clear scope that defines which cloud accounts, subscriptions, or projects are in scope, which services and resources may be tested, any exclusions or time-of-day restrictions, escalation procedures for critical findings, and communication channels and emergency contacts. For multi-cloud environments — increasingly common among San Francisco technology companies that leverage best-of-breed services across providers — scoping must address each cloud platform independently.

Phase 2: External Reconnaissance

Cloud penetration testing begins with external reconnaissance to identify the target's cloud footprint without authenticated access. This phase includes:

• DNS enumeration to identify cloud-hosted services and their associated providers
• Certificate transparency log analysis to discover cloud-hosted domains and subdomains
• Public storage bucket and blob enumeration across all three major providers
• Identification of exposed cloud management interfaces and API endpoints
• Analysis of publicly available metadata, including error messages that reveal cloud architecture details

Phase 3: Authenticated Enumeration

With authorized credentials, we perform comprehensive enumeration of the cloud environment's configuration. This is the most technically intensive phase and covers identity and access management configurations across all accounts, network architecture including VPCs, subnets, security groups, and firewall rules, storage configurations and data exposure analysis, compute resources and their associated roles and permissions, serverless function configurations and execution roles, container orchestration security including Kubernetes RBAC and network policies, logging, monitoring, and alerting configurations, and encryption configurations for data at rest and in transit.

Phase 4: Vulnerability Identification and Exploitation

Based on the findings from enumeration, we identify and safely exploit vulnerabilities to demonstrate their real-world impact. Cloud-specific exploitation techniques include:

• Privilege Escalation: Chaining IAM misconfigurations to escalate from limited access to administrative control. In AWS, this might involve exploiting iam:PassRole permissions combined with Lambda function creation. In Azure, exploiting Application Administrator or Cloud Application Administrator roles to gain Global Administrator access.
• Lateral Movement: Moving between cloud accounts, subscriptions, or projects using trust relationships, shared credentials, and cross-account/cross-project access configurations.
• Data Exfiltration: Demonstrating the ability to access and extract sensitive data from storage services, databases, and data warehouses through misconfigured access controls.
• Persistence Establishment: Creating backdoor access mechanisms — such as additional IAM users, roles with external trust policies, or API keys — to demonstrate how attackers maintain long-term access to compromised environments.

Phase 5: Reporting and Remediation Guidance

The final phase produces a comprehensive report that includes an executive summary suitable for board-level presentation, detailed technical findings with evidence and reproduction steps, risk ratings that account for the cloud-specific context of each vulnerability, prioritized remediation recommendations with provider-specific implementation guidance, and strategic recommendations for improving the organization's cloud security posture over time.

"A cloud penetration test that simply runs automated scanning tools against cloud infrastructure is not a penetration test — it is a configuration review with extra steps. Genuine cloud penetration testing requires the creativity, technical depth, and adversarial mindset of experienced offensive security professionals."

Common Misconfigurations We Find Across All Providers

While each cloud provider has unique security characteristics, several misconfiguration patterns appear consistently across AWS, Azure, and GCP environments:

• Excessive Permissions: The single most common finding across all cloud penetration tests. Identity principals are routinely granted far more access than their functional role requires.
• Missing Logging and Monitoring: CloudTrail, Azure Activity Log, and Cloud Audit Logs are frequently not enabled for all regions, or their data is not monitored by the security operations team.
• Unencrypted Data: Data at rest encryption is not enabled for all storage resources, and encryption in transit is not enforced for all internal communications.
• Stale Credentials: Access keys, service account keys, and service principal secrets that have not been rotated in months or years provide persistent access vectors.
• Network Exposure: Management interfaces, development services, and internal APIs exposed to the public internet through misconfigured security groups, firewall rules, or load balancer configurations.
• Missing MFA: Multi-factor authentication not enforced for console access to cloud management portals, particularly for privileged accounts.

Building a Cloud Security Testing Program

A single cloud penetration test provides a valuable point-in-time assessment, but the dynamic nature of cloud environments demands an ongoing security testing program. Organizations should consider the following components:

• Quarterly Penetration Tests: Full-scope penetration tests conducted at least quarterly, or whenever significant architectural changes are deployed.
• Continuous Cloud Security Posture Management: Automated tools that continuously monitor cloud configurations against security baselines and alert on drift.
• Infrastructure as Code Review: Security review of Terraform, CloudFormation, ARM templates, and other IaC definitions before deployment to prevent misconfigurations from reaching production.
• Cloud-Specific Threat Modeling: Regular threat modeling exercises that consider cloud-specific attack vectors, including supply chain risks from marketplace images, shared responsibility gaps, and provider-specific exploitation techniques.

Conclusion

Cloud penetration testing is an essential discipline for any organization that depends on cloud infrastructure — which, in 2025, means virtually every enterprise. The unique characteristics of AWS, Azure, and GCP environments demand specialized testing approaches that go far beyond traditional network penetration testing.

The organizations that invest in comprehensive cloud security assessments — conducted by penetration testers with deep expertise across all major cloud platforms — are the ones that discover and remediate critical vulnerabilities before attackers exploit them. At CyberGuards, our San Francisco-based team brings extensive multi-cloud penetration testing experience to every engagement, helping organizations across the Bay Area and nationwide secure their cloud environments against the full spectrum of modern threats.

Whether your organization operates in a single cloud or manages a complex multi-cloud architecture, the time to assess your cloud security posture is now. The attack surface is vast, the misconfigurations are common, and the adversaries are actively looking.