CVE-2024-37293 in aws-deployment-framework
Summary
by MITRE • 06/11/2024
The AWS Deployment Framework (ADF) is a framework to manage and deploy resources across multiple AWS accounts and regions within an AWS Organization. ADF allows for staged, parallel, multi-account, cross-region deployments of applications or resources via the structure defined in AWS Organizations while taking advantage of services such as AWS CodePipeline, AWS CodeBuild, and AWS CodeCommit to alleviate the heavy lifting and management compared to a traditional CI/CD setup. ADF contains a bootstrap process that is responsible to deploy ADF's bootstrap stacks to facilitate multi-account cross-region deployments. The ADF bootstrap process relies on elevated privileges to perform this task. Two versions of the bootstrap process exist; a code-change driven pipeline using AWS CodeBuild and an event-driven state machine using AWS Lambda. If an actor has permissions to change the behavior of the CodeBuild project or the Lambda function, they would be able to escalate their privileges.
Prior to version 4.0.0, the bootstrap CodeBuild role provides access to the `sts:AssumeRole` operation without further restrictions. Therefore, it is able to assume into any AWS Account in the AWS Organization with the elevated privileges provided by the cross-account access role. By default, this role is not restricted when it is created by AWS Organizations, providing Administrator level access to the AWS resources in the AWS Account. The patches for this issue are included in `aws-deployment-framework` version 4.0.0.
As a temporary mitigation, add a permissions boundary to the roles created by ADF in the management account. The permissions boundary should deny all IAM and STS actions. This permissions boundary should be in place until you upgrade ADF or bootstrap a new account. While the permissions boundary is in place, the account management and bootstrapping of accounts are unable to create, update, or assume into roles. This mitigates the privilege escalation risk, but also disables ADF's ability to create, manage, and bootstrap accounts.
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Analysis
by VulDB Data Team • 08/17/2024
The AWS Deployment Framework (ADF) represents a sophisticated multi-account, cross-region deployment solution that leverages AWS Organizations to streamline infrastructure management across complex cloud environments. This framework utilizes AWS CodePipeline, CodeBuild, and CodeCommit services to automate deployment processes while maintaining security boundaries through organizational structures. The bootstrap process within ADF serves as a critical initialization mechanism that deploys foundational stacks necessary for cross-account and cross-region operations. This process requires elevated privileges to function properly, as it must establish the necessary infrastructure components across multiple AWS accounts within an organization. The vulnerability in question specifically targets the privilege escalation capabilities inherent in the bootstrap process, creating a significant security risk for organizations relying on ADF for their deployment operations.
The technical flaw exists within the bootstrap CodeBuild role's permission structure, which prior to version 4.0.0 lacked proper restrictions on the sts:AssumeRole operation. This unrestricted access allows malicious actors to assume roles in any AWS account within the organization, effectively bypassing the normal security boundaries that should protect individual accounts. The vulnerability stems from the default behavior of AWS Organizations when creating roles, which typically grant Administrator level access to the accounts where roles are created. This design flaw creates a privilege escalation vector where an attacker with access to modify the CodeBuild project or Lambda function can leverage the elevated permissions to gain unauthorized access to all accounts within the AWS Organization. The issue manifests as a direct violation of the principle of least privilege, as the bootstrap process unnecessarily exposes full administrative capabilities across the entire organizational structure.
The operational impact of this vulnerability extends beyond simple privilege escalation, creating a potential pathway for comprehensive account compromise across an entire AWS Organization. An attacker exploiting this vulnerability could gain access to sensitive resources, data, and infrastructure components across all accounts within the organization, potentially leading to data breaches, service disruption, and compliance violations. The risk is particularly severe because the bootstrap process is designed to be automated and frequently executed, providing multiple opportunities for exploitation. Organizations using ADF for their deployment workflows face significant exposure, as the vulnerability affects the foundational security mechanisms that protect their multi-account environments. The potential for cascading security failures increases when considering that many organizations rely on ADF for critical business applications and infrastructure deployments.
The recommended mitigation strategy involves implementing a permissions boundary on roles created by ADF in the management account, specifically denying all IAM and STS actions. This approach aligns with the principle of least privilege and provides a temporary safeguard while organizations upgrade to the patched version 4.0.0. However, this mitigation introduces operational constraints that must be carefully considered, as it prevents the account management and bootstrapping functions from creating, updating, or assuming into roles. This temporary restriction effectively disables key ADF capabilities until the upgrade is complete, requiring organizations to balance immediate security concerns with operational continuity. The mitigation approach demonstrates the complexity of addressing privilege escalation vulnerabilities in cloud environments, where security controls must be carefully balanced against functional requirements. Organizations should also consider implementing additional monitoring and alerting for unusual role assumption patterns, as outlined in the MITRE ATT&CK framework's privilege escalation techniques. This vulnerability exemplifies the importance of proper role-based access control and the need for regular security assessments of automation frameworks within cloud organizations, aligning with the security controls recommended in the CWE database for privilege escalation vulnerabilities.