A recently patched high-severity vulnerability in Google Cloud Platform’s Cloud Composer service, dubbed ConfusedComposer, could have allowed attackers to hijack cloud workflows and gain elevated privileges. This flaw in the managed Apache Airflow service highlights significant risks in automated cloud orchestration systems, particularly when handling third-party package dependencies.
Executive Summary for Security Leadership
The ConfusedComposer vulnerability (unassigned CVE) affected Google Cloud Composer’s package installation mechanism, allowing privilege escalation through malicious PyPI packages. Attackers with basic composer.environments.update permissions could potentially gain control over critical cloud resources. Google addressed the issue on April 13, 2025, by implementing environment-specific service accounts.
- Impact: Privilege escalation to Cloud Build service account (high-permission IAM roles)
- Attack Vector: Malicious PyPI package installation
- Root Cause: Cloud Build’s default service account usage during package installation
- Affected Versions: All Cloud Composer versions prior to January 15, 2025 patch
- Mitigation: Automatic update applied by Google; manual verification recommended
Technical Analysis of ConfusedComposer
The vulnerability stemmed from Cloud Composer’s reliance on Cloud Build for installing Python packages from PyPI. When users added dependencies to their Composer environments, the service would execute package installation scripts using the default Cloud Build service account, which typically had extensive permissions for Cloud Storage and Artifact Registry access.
Attackers could craft malicious Python packages containing setup scripts that executed arbitrary commands with these elevated privileges. The following example demonstrates how an attacker might abuse this to create new service account keys:
# Malicious setup.py in PyPI package
import os
os.system("gcloud iam service-accounts keys create [email protected]")
This execution context provided several dangerous possibilities, including the ability to modify IAM policies, access sensitive data in Cloud Storage, or deploy malicious artifacts to internal repositories. The attack required initial access to Cloud Composer environment modification privileges, which are commonly granted to development teams.
Detection and Remediation
Organizations using Cloud Composer should verify they’re running patched versions (post-January 15, 2025 release). Google’s fix implemented environment-specific service accounts with reduced privileges for package installation. Additional security measures include:
| Action | Command/Procedure |
|---|---|
| Verify Cloud Composer version | gcloud composer environments describe [ENVIRONMENT_NAME] –location [LOCATION] |
| Review IAM permissions | gcloud projects get-iam-policy [PROJECT_ID] |
| Audit PyPI packages | Check requirements.txt in all Composer environments |
Security teams should monitor for suspicious activities in Cloud Build logs and unexpected service account key creations. The following GCP logging filter can help identify potential exploitation attempts:
resource.type="cloud_composer_environment"
protoPayload.methodName="environments.update"
Security Implications
This vulnerability demonstrates the risks inherent in cloud workflow automation systems that combine high-privilege service accounts with third-party package execution. The attack surface expands significantly when services automatically execute code from public repositories without proper sandboxing.
Similar patterns have been observed in other cloud services, particularly those that:
- Execute user-provided code in build processes
- Use shared service accounts across environments
- Automatically process dependencies from public repositories
Google’s response included not only patching the immediate vulnerability but also implementing additional safeguards in Cloud Composer’s package installation process. These changes reflect evolving best practices for cloud service security.
Conclusion
The ConfusedComposer vulnerability serves as an important case study in cloud service security, particularly regarding privilege management in automated workflows. While Google has addressed the immediate issue, organizations should review their cloud environments for similar patterns where high-privilege service accounts interact with potentially untrusted code execution.
Future security improvements in this space may include stricter default permissions for automated services, enhanced package verification mechanisms, and better isolation between workflow execution contexts. Regular audits of cloud permissions and dependency sources remain essential security practices.
References
- “ConfusedComposer: A Privilege Escalation Vulnerability Impacting GCP Composer,” Tenable Blog, 2025. [Online]. Available: https://www.tenable.com/blog/confusedcomposer-a-privilege-escalation-vulnerability-impacting-gcp-composer
- Google Cloud Composer Release Notes, January 15, 2025. [Online]. Available: https://cloud.google.com/composer/docs/release-notes#January_15_2025
- Google Cloud Security Bulletins. [Online]. Available: https://cloud.google.com/support/bulletins
- CVE Mitre Database. [Online]. Available: https://cve.mitre.org/
- GBHackers Security. [Online]. Available: https://gbhackers.com
