Jun 11 2024


Category: Hacking,Risk Assessmentdisc7 @ 8:24 am

A significant security vulnerability has been discovered by Tenable Research that affects Azure customers relying on Service Tags for their firewall rules. This vulnerability allows attackers to bypass Azure firewall rules, posing a substantial risk to organizations using these configurations. Here’s an in-depth look at the vulnerability, how it can be exploited, and crucial defensive measures to mitigate the risk.

Azure Security


Tenable Research initially uncovered the vulnerability within Azure Application Insights, a service designed to monitor and analyze web applications’ performance and availability. The Availability Tests feature of Azure Application Insights, intended to check the accessibility and performance of applications, was found to be susceptible to abuse. Users can control server-side requests in these tests, including adding custom headers and changing HTTP methods. This control can be exploited by attackers to forge requests from trusted services, mimicking a server-side request forgery (SSRF) attack.


Upon further investigation, Tenable Research found that the vulnerability extends beyond Azure Application Insights to more than 10 other Azure services. These include:

  • Azure DevOps
  • Azure Machine Learning
  • Azure Logic Apps
  • Azure Container Registry
  • Azure Load Testing
  • Azure API Management
  • Azure Data Factory
  • Azure Action Group
  • Azure AI Video Indexer
  • Azure Chaos Studio

Each of these services allows users to control server-side requests and has an associated Service Tag, creating potential security risks if not properly mitigated.


Attackers can exploit the vulnerability in Azure Service Tags by abusing the Availability Tests feature in Azure Application Insights. Below are detailed steps and examples to illustrate how an attacker can exploit this vulnerability:

1. Setting Up the Availability Test:

  • Example Scenario: An attacker identifies an internal web service within a victim’s Azure environment that is protected by a firewall rule allowing traffic only from Azure Application Insights.
  • Action: The attacker sets up an Availability Test in Azure Application Insights, configuring it to target the internal web service.

2. Customizing the Request:

  • Manipulating Headers: The attacker customizes the HTTP request headers to include authorization tokens or other headers that may be expected by the target service.
  • Changing HTTP Methods: The attacker can change the HTTP method (e.g., from GET to POST) to perform actions such as submitting data or invoking actions on the target service.
  • Example Customization: The attacker configures the test to send a POST request with a custom header “Authorization: Bearer <malicious-token>”.

3. Sending the Malicious Request:

  • Firewall Bypass: The crafted request is sent through the Availability Test. Since it originates from a trusted Azure service (Application Insights), it bypasses the firewall rules based on Service Tags.
  • Example Attack: The Availability Test sends the POST request with the custom header to the internal web service, which processes the request as if it were from a legitimate source.

4. Accessing Internal Resources:

  • Unauthorized Access: The attacker now has access to internal APIs, databases, or other services that were protected by the firewall.
  • Exfiltration and Manipulation: The attacker can exfiltrate sensitive data, manipulate internal resources, or use the access to launch further attacks.
  • Example Impact: The attacker retrieves confidential data from an internal API or modifies configuration settings in an internal service.


Scenario: An organization uses Azure Application Insights to monitor an internal financial service. The service is protected by a firewall rule that allows access only from the ApplicationInsightsAvailability Service Tag.

  1. Deploying an Internal Azure App Service:
    • The organization has a financial application hosted on an Azure App Service with firewall rules configured to accept traffic only from the ApplicationInsightsAvailability Service Tag.
  2. Attempted Access by the Attacker:
    • The attacker discovers the endpoint of the internal financial application and attempts to access it directly. The firewall blocks this attempt, returning a forbidden response.
  3. Exploiting the Vulnerability:
    • Setting Up the Test: The attacker sets up an Availability Test in Azure Application Insights targeting the internal financial application.
    • Customizing the Request: The attacker customizes the test to send a POST request with a payload that triggers a financial transaction, adding a custom header “Authorization: Bearer <malicious-token>”.
    • Sending the Request: The Availability Test sends the POST request to the internal financial application, bypassing the firewall.
  4. Gaining Unauthorized Access:
    • The financial application processes the POST request, believing it to be from a legitimate source. The attacker successfully triggers the financial transaction.
    • Exfiltration: The attacker sets up another Availability Test to send GET requests with custom headers to extract financial records from the application.


1. Chain Attacks:

  • Attackers can chain multiple vulnerabilities or services together to escalate their privileges and impact. For example, using the initial access gained from the Availability Test to find other internal services or to escalate privileges within the Azure environment.

2. Lateral Movement:

  • Once inside the network, attackers can move laterally to compromise other services or extract further data. They might use other Azure services like Azure DevOps or Azure Logic Apps to find additional entry points or sensitive data.

3. Persistent Access:

  • Attackers can set up long-term Availability Tests that periodically execute, ensuring continuous access to the internal services. They might use these persistent tests to maintain a foothold within the environment, continuously exfiltrating data or executing malicious activities.


To mitigate the risks associated with this vulnerability, Azure customers should implement several defensive measures:

1. Analyze and Update Network Rules:

  • Conduct a thorough review of network security rules.
  • Identify and analyze any use of Service Tags in firewall rules.
  • Assume services protected only by Service Tags may be vulnerable.

2. Implement Strong Authentication and Authorization:

  • Add robust authentication and authorization mechanisms.
  • Use Azure Active Directory (Azure AD) for managing access.
  • Enforce multi-factor authentication and least privilege principles.

3. Enhance Network Isolation:

  • Use network security groups (NSGs) and application security groups (ASGs) for granular isolation.
  • Deploy Azure Private Link to keep traffic within the Azure network.

4. Monitor and Audit Network Traffic:

  • Enable logging and monitoring of network traffic.
  • Use Azure Monitor and Azure Security Center to set up alerts for unusual activities.
  • Regularly review logs and audit trails.

5. Regularly Update and Patch Services:

  • Keep all Azure services and applications up to date with security patches.
  • Monitor security advisories from Microsoft and other sources.
  • Apply updates promptly to minimize risk.

6. Use Azure Policy to Enforce Security Configurations:

  • Deploy Azure Policy to enforce security best practices.
  • Create policies that require strong authentication and proper network configurations.
  • Use Azure Policy initiatives for consistent application across resources.

7. Conduct Security Assessments and Penetration Testing:

  • Perform regular security assessments and penetration testing.
  • Engage with security experts or third-party services for thorough reviews.
  • Use tools like Azure Security Benchmark and Azure Defender.

8. Educate and Train Staff:

  • Provide training on risks and best practices related to Azure Service Tags and network security.
  • Ensure staff understand the importance of multi-layered security.
  • Equip teams to implement and manage security measures effectively.


The vulnerability discovered by Tenable Research highlights significant risks associated with relying solely on Azure Service Tags for firewall rules. By understanding the nature of the vulnerability and implementing the recommended defensive measures, Azure customers can better protect their environments and mitigate potential threats. Regular reviews, updates, and a multi-layered security approach are essential to maintaining a secure Azure environment.

Azure Security

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Tags: Azure Security

Mar 21 2024


Continuous Threat Exposure Management (CTEM) is an evolving cybersecurity practice focused on identifying, assessing, prioritizing, and addressing security weaknesses and vulnerabilities in an organization’s digital assets and networks continuously. Unlike traditional approaches that might assess threats periodically, CTEM emphasizes a proactive, ongoing process of evaluation and mitigation to adapt to the rapidly changing threat landscape. Here’s a closer look at its key components:

  1. Identification: CTEM starts with the continuous identification of all digital assets within an organization’s environment, including on-premises systems, cloud services, and remote endpoints. It involves understanding what assets exist, where they are located, and their importance to the organization.
  2. Assessment: Regular and ongoing assessments of these assets are conducted to identify vulnerabilities, misconfigurations, and other security weaknesses. This process often utilizes automated scanning tools and threat intelligence to detect issues that could be exploited by attackers.
  3. Prioritization: Not all vulnerabilities pose the same level of risk. CTEM involves prioritizing these weaknesses based on their severity, the value of the affected assets, and the potential impact of an exploit. This helps organizations focus their efforts on the most critical issues first.
  4. Mitigation and Remediation: Once vulnerabilities are identified and prioritized, CTEM focuses on mitigating or remedying these issues. This can involve applying patches, changing configurations, or implementing other security measures to reduce the risk of exploitation.
  5. Continuous Improvement: CTEM is a cyclical process that feeds back into itself. The effectiveness of mitigation efforts is assessed, and the approach is refined over time to improve security posture continuously.

The goal of CTEM is to reduce the “attack surface” of an organization—minimizing the number of vulnerabilities that could be exploited by attackers and thereby reducing the organization’s overall risk. By continuously managing and reducing exposure to threats, organizations can better protect against breaches and cyber attacks.


Continuous Threat Exposure Management (CTEM) represents a proactive and ongoing approach to managing cybersecurity risks, distinguishing itself from traditional, more reactive security practices. Understanding the differences between CTEM and alternative approaches can help organizations choose the best strategy for their specific needs and threat landscapes. Let’s compare CTEM with some of these alternative approaches:


  • Periodic Security Assessments typically involve scheduled audits or evaluations of an organization’s security posture at fixed intervals (e.g., quarterly or annually). This approach may fail to catch new vulnerabilities or threats that emerge between assessments, leaving organizations exposed for potentially long periods.
  • CTEM, on the other hand, emphasizes continuous monitoring and assessment of threats and vulnerabilities. It ensures that emerging threats can be identified and addressed in near real-time, greatly reducing the window of exposure.


  • Penetration Testing is a targeted approach where security professionals simulate cyber-attacks on a system to identify vulnerabilities. While valuable, penetration tests are typically conducted annually or semi-annually and might not uncover vulnerabilities introduced between tests.
  • CTEM complements penetration testing by continuously scanning for and identifying vulnerabilities, ensuring that new threats are addressed promptly and not just during the next scheduled test.


  • Incident Response Planning focuses on preparing for, detecting, responding to, and recovering from cybersecurity incidents. It’s reactive by nature, kicking into gear after an incident has occurred.
  • CTEM works upstream of incident response by aiming to prevent incidents before they happen through continuous threat and vulnerability management. While incident response is a critical component of a comprehensive cybersecurity strategy, CTEM can reduce the likelihood and impact of incidents occurring in the first place.


  • Traditional Vulnerability Management involves identifying, classifying, remediating, and mitigating vulnerabilities within software and hardware. While it can be an ongoing process, it often lacks the continuous, real-time monitoring and prioritization framework of CTEM.
  • CTEM enhances traditional vulnerability management by integrating it into a continuous cycle that includes real-time detection, prioritization based on current threat intelligence, and immediate action to mitigate risks.


  • Real-Time Threat Intelligence: CTEM integrates the latest threat intelligence to ensure that the organization’s security measures are always ahead of potential threats.
  • Automation and Integration: By leveraging automation and integrating various security tools, CTEM can streamline the process of threat and vulnerability management, reducing the time from detection to remediation.
  • Risk-Based Prioritization: CTEM prioritizes vulnerabilities based on their potential impact on the organization, ensuring that resources are allocated effectively to address the most critical issues first.

CTEM offers a comprehensive and continuous approach to cybersecurity, focusing on reducing exposure to threats in a dynamic and ever-evolving threat landscape. While alternative approaches each have their place within an organization’s overall security strategy, integrating them with CTEM principles can provide a more resilient and responsive defense mechanism against cyber threats.


Implementing Continuous Threat Exposure Management (CTEM) within an AWS Cloud environment involves leveraging AWS services and tools, alongside third-party solutions and best practices, to continuously identify, assess, prioritize, and remediate vulnerabilities and threats. Here’s a detailed example of how CTEM can be applied in AWS:


  • AWS Config: Use AWS Config to continuously monitor and record AWS resource configurations and changes, helping to identify which assets exist in your environment, their configurations, and their interdependencies.
  • AWS Resource Groups: Organize resources by applications, projects, or environments to simplify management and monitoring.


  • Amazon Inspector: Automatically assess applications for vulnerabilities or deviations from best practices, especially important for EC2 instances and container-based applications.
  • AWS Security Hub: Aggregates security alerts and findings from various AWS services (like Amazon Inspector, Amazon GuardDuty, and IAM Access Analyzer) and supported third-party solutions to give a comprehensive view of your security and compliance status.


  • AWS Security Hub: Provides a consolidated view of security alerts and findings rated by severity, allowing you to prioritize issues based on their potential impact on your AWS environment.
  • Custom Lambda Functions: Create AWS Lambda functions to automate the analysis and prioritization process, using criteria specific to your organization’s risk tolerance and security posture.


  • AWS Systems Manager Patch Manager: Automate the process of patching managed instances with both security and non-security related updates.
  • CloudFormation Templates: Use AWS CloudFormation to enforce infrastructure configurations that meet your security standards. Quickly redeploy configurations if deviations are detected.
  • Amazon EventBridge and AWS Lambda: Automate responses to security findings. For example, if Security Hub detects a critical vulnerability, EventBridge can trigger a Lambda function to isolate affected instances or apply necessary patches.


  • AWS Well-Architected Tool: Regularly review your workloads against AWS best practices to identify areas for improvement.
  • Feedback Loop: Implement a feedback loop using AWS CloudWatch Logs and Amazon Elasticsearch Service to analyze logs and metrics for security insights, which can inform the continuous improvement of your CTEM processes.


Imagine you’re managing a web application hosted on AWS. Here’s how CTEM comes to life:

  • Identification: Use AWS Config and Resource Groups to maintain an updated inventory of your EC2 instances, RDS databases, and S3 buckets critical to your application.
  • Assessment: Employ Amazon Inspector to regularly scan your EC2 instances for vulnerabilities and AWS Security Hub to assess your overall security posture across services.
  • Prioritization: Security Hub alerts you to a critical vulnerability in an EC2 instance running your application backend. It’s flagged as high priority due to its access to sensitive data.
  • Mitigation and Remediation: You automatically trigger a Lambda function through EventBridge based on the Security Hub finding, which isolates the affected EC2 instance and initiates a patching process via Systems Manager Patch Manager.
  • Continuous Improvement: Post-incident, you use the AWS Well-Architected Tool to evaluate your architecture. Insights gained lead to the implementation of stricter IAM policies and enhanced monitoring with CloudWatch and Elasticsearch for anomaly detection.

This cycle of identifying, assessing, prioritizing, mitigating, and continuously improving forms the core of CTEM in AWS, helping to ensure that your cloud environment remains secure against evolving threats.


Implementing Continuous Threat Exposure Management (CTEM) in Azure involves utilizing a range of Azure services and features designed to continuously identify, assess, prioritize, and mitigate security risks. Below is a step-by-step example illustrating how an organization can apply CTEM principles within the Azure cloud environment:


  • Azure Resource Graph: Use Azure Resource Graph to query and visualize all resources across your Azure environment. This is crucial for understanding what assets you have, their configurations, and their interrelationships.
  • Azure Tags: Implement tagging strategies to categorize resources based on sensitivity, department, or environment. This aids in the prioritization process later on.


  • Azure Security Center: Enable Azure Security Center (ASC) at the Standard tier to conduct continuous security assessments across your Azure resources. ASC provides security recommendations and assesses your resources for vulnerabilities and misconfigurations.
  • Azure Defender: Integrated into Azure Security Center, Azure Defender provides advanced threat protection for workloads running in Azure, including virtual machines, databases, and containers.


  • ASC Secure Score: Use the Secure Score in Azure Security Center as a metric to prioritize security recommendations based on their potential impact on your environment’s security posture.
  • Custom Logic with Azure Logic Apps: Develop custom workflows using Azure Logic Apps to prioritize alerts based on your organization’s specific criteria, such as asset sensitivity or compliance requirements.


  • Azure Automation: Employ Azure Automation to run remediation scripts or configurations management across your Azure VMs and services. This can be used to automatically apply patches, update configurations, or manage access controls in response to identified vulnerabilities.
  • Azure Logic Apps: Trigger automated workflows in response to security alerts. For example, if Azure Security Center identifies an unprotected data storage, an Azure Logic App can automatically initiate a workflow to apply the necessary encryption settings.


  • Azure Monitor: Utilize Azure Monitor to collect, analyze, and act on telemetry data from your Azure resources. This includes logs, metrics, and alerts that can help you detect and respond to threats in real-time.
  • Azure Sentinel: Deploy Azure Sentinel, a cloud-native SIEM service, for a more comprehensive security information and event management solution. Sentinel can collect data across all users, devices, applications, and infrastructure, both on-premises and in multiple clouds.


  • Azure Policy: Implement Azure Policy to enforce organizational standards and to assess compliance at scale. Continuous evaluation of your configurations against these policies ensures compliance and guides ongoing improvement.
  • Feedback Loops: Establish feedback loops using the insights gained from Azure Monitor, Azure Security Center, and Azure Sentinel to refine and improve your security posture continuously.


Let’s say you’re managing a web application hosted in Azure, utilizing Azure App Service for the web front end, Azure SQL Database for data storage, and Azure Blob Storage for unstructured data.

  • Identification: You catalog all resources related to the web application using Azure Resource Graph and apply tags based on sensitivity and function.
  • Assessment: Azure Security Center continuously assesses these resources for vulnerabilities, such as misconfigurations or outdated software.
  • Prioritization: Based on the Secure Score and custom logic in Azure Logic Apps, you prioritize a detected SQL injection vulnerability in Azure SQL Database as critical.
  • Mitigation: Azure Automation is triggered to isolate the affected database and apply a patch. Concurrently, Azure Logic Apps notifies the security team and logs the incident for review.
  • Monitoring: Azure Monitor and Azure Sentinel provide ongoing surveillance, detecting any unusual access patterns or potential breaches.
  • Improvement: Insights from the incident lead to a review and enhancement of the application’s code and a reinforcement of security policies through Azure Policy to prevent similar vulnerabilities in the future.

By following these steps and utilizing Azure’s comprehensive suite of security tools, organizations can implement an effective CTEM strategy that continuously protects against evolving cyber threats.


Implementing Continuous Threat Exposure Management (CTEM) in cloud environments like AWS and Azure involves a series of strategic steps, leveraging each platform’s unique tools and services. The approach combines best practices for security and compliance management, automation, and continuous monitoring. Here’s a guide to get started with CTEM in both AWS and Azure:


  1. Understand Your Environment
    • Catalogue your cloud resources and services.
    • Understand the data flow and dependencies between your cloud assets.
  2. Define Your Security Policies and Objectives
    • Establish what your security baseline looks like.
    • Define key compliance requirements and security objectives.
  3. Integrate Continuous Monitoring Tools
    • Leverage cloud-native tools for threat detection, vulnerability assessment, and compliance monitoring.
    • Integrate third-party security tools if necessary for enhanced capabilities.
  4. Automate Security Responses
    • Implement automated responses to common threats and vulnerabilities.
    • Use cloud services to automate patch management and configuration adjustments.
  5. Continuously Assess and Refine
    • Regularly review security policies and controls.
    • Adjust based on new threats, technological advancements, and changes in the business environment.


  1. Enable AWS Security Services
    • Utilize AWS Security Hub for a comprehensive view of your security state and to centralize and prioritize security alerts.
    • Use Amazon Inspector for automated security assessments to help find vulnerabilities or deviations from best practices.
    • Implement AWS Config to continuously monitor and record AWS resource configurations.
  2. Automate Response with AWS Lambda
    • Use AWS Lambda to automate responses to security findings, such as isolating compromised instances or automatically patching vulnerabilities.
  3. Leverage Amazon CloudWatch
    • Employ CloudWatch for monitoring and alerting based on specific metrics or logs that indicate potential security threats.


  1. Utilize Azure Security Tools
    • Activate Azure Security Center for continuous assessment and security recommendations. Use its advanced threat protection features to detect and mitigate threats.
    • Implement Azure Sentinel for SIEM (Security Information and Event Management) capabilities, integrating it with other Azure services for a comprehensive security analysis and threat detection.
  2. Automate with Azure Logic Apps
    • Use Azure Logic Apps to automate responses to security alerts, such as sending notifications or triggering remediation processes.
  3. Monitor with Azure Monitor
    • Leverage Azure Monitor to collect, analyze, and act on telemetry data from your Azure and on-premises environments, helping you detect and respond to threats in real-time.


  • Continuous Compliance: Use policy-as-code to enforce and automate compliance standards across your cloud environments.
  • Identity and Access Management (IAM): Implement strict IAM policies to ensure least privilege access and utilize multi-factor authentication (MFA) for enhanced security.
  • Encrypt Data: Ensure data at rest and in transit is encrypted using the cloud providers’ encryption capabilities.
  • Educate Your Team: Regularly train your team on the latest cloud security best practices and the specific tools and services you are using.

Implementing CTEM in AWS and Azure requires a deep understanding of each cloud environment’s unique features and capabilities. By leveraging the right mix of tools and services, organizations can create a robust security posture that continuously identifies, assesses, and mitigates threats.

AWS Security

Azure Security

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Tags: AWS, AWS security, Azure, Azure Security, cloud security