Shadow Operations: Unraveling the Secrets of AWS SSM

Introduction

Amazon Web Services (AWS) Systems Manager (SSM) offers management and insights to AWS resources, streamlining operations through automated administrative tasks. However, its broad capabilities can also pose risks if not securely managed. This article explores the vulnerabilities associated with SSM agents, common attack tactics, techniques, and procedures (TTPs), and provides a detailed walkthrough of a potential attack scenario, along with mitigation strategies.

What is AWS SSM?

AWS Systems Manager (SSM) helps manage and configure servers and VMs in the cloud or on-premises. SSM Agent, installed on these machines, communicates with Systems Manager to execute tasks remotely. SSM's features include running scripts, managing patches, and collecting inventory data, making it integral to operational workflows.

How to Use AWS SSM

To utilize AWS SSM effectively:

1. Install SSM Agent: The agent must be installed on each instance you wish to manage.
2. Set IAM Roles: Assign appropriate IAM roles to the instance to allow communication with the Systems Manager.
3. Use SSM Documents: Execute administrative tasks by creating and running SSM Documents, which are JSON files that define the actions SSM should perform on your instances.

Potential Threats and Attack Tactics, Techniques, and Procedures (TTPs)

While AWS SSM provides powerful tools for managing and automating cloud environments, it also presents a number of security threats that can be exploited through specific tactics, techniques, and procedures (TTPs). Understanding these threats in conjunction with their corresponding TTPs, aligned with the MITRE ATT&CK framework, is crucial for identifying and mitigating potential risks.

Unauthorized Access and Execution

• Tactic (T1190 - Exploit Public-Facing Application): Attackers may gain initial access through exposed credentials or vulnerabilities in public-facing applications. Once inside, they can exploit the SSM agent to execute commands.
• Technique (T1059 - Command and Scripting Interpreter): With access to SSM, attackers can execute arbitrary scripts or commands, effectively taking control over cloud resources and automating the spread of malicious activities across multiple systems.

Misconfigurations and Privilege Escalation

• Tactic (T1068 - Exploitation for Privilege Escalation): Poorly configured IAM roles and policies can be exploited to perform actions that would normally require higher privileges. Attackers might modify SSM documents or create new ones to escalate their privileges within the cloud environment.
• Technique (T1078 - Valid Accounts): By using legitimate credentials, either stolen or mistakenly exposed, attackers can interact with SSM as legitimate users, making detection more challenging.

Eavesdropping and Defense Evasion

• Tactic (T1020 - Automated Exfiltration): Attackers can use SSM to facilitate data exfiltration by scripting the collection and transmission of sensitive information.
• Technique (T1070 - Indicator Removal on Host): To avoid detection, attackers might use SSM capabilities to clear logs and other indicators of their presence or activities within the cloud environment.

Attack Walkthrough

Scenario: Lateral Movement and Data Exfiltration via AWS SSM

1. Initial Access: The attacker begins by exploiting a weakly secured AWS IAM role associated with a publicly accessible application. By using this role, they gain initial foothold into the AWS environment.
2. Discovery and Lateral Movement:
   • Discovery: Once inside, the attacker uses the SSM agent to query and discover other instances within the environment that can be accessed.
   • Lateral Movement: Utilizing custom SSM documents, the attacker moves laterally across the network, installing additional payloads on multiple instances.
3. Privilege Escalation and Command Execution:
   • Privilege Escalation: The attacker escalates privileges by modifying existing IAM policies attached to the compromised instance or creating new ones that allow further access to sensitive resources.
   • Command Execution: With escalated privileges, the attacker executes a series of commands via SSM to deploy malware or ransomware across the network.
4. Data Exfiltration:
   • The attacker uses SSM to execute scripts that package and transmit sensitive data to external servers. This might include customer data, intellectual property, or internal communications.
5. Cleanup and Defense Evasion:
   • To cover their tracks, the attacker uses SSM to delete logs and other forensic evidence. They might also unregister the SSM agent on compromised instances to avoid subsequent detection by security tools.

Code Example of Malicious SSM Document Execution:

Mitigation Strategies

Implementing robust security measures is essential to mitigate the risks associated with AWS SSM:

1. IAM Role Security: Enforce strict IAM policies and roles that limit permissions to the least privilege necessary.
2. Regular Monitoring and Auditing: Employ advanced monitoring solutions to detect and alert on unusual SSM activities or IAM changes.
3. Incident Response Plan: Develop and regularly update an incident response plan that includes procedures for responding to SSM-related security incidents.

Cyngular Security's CIRA Platform

To further secure your cloud environment, consider integrating Cyngular Security's CIRA platform. It enhances your security posture by providing advanced investigation and response capabilities, enabling your team to address threats swiftly and effectively. By adopting Cyngular Security's CIRA, you empower your organization with proactive and automated security measures that protect your cloud assets.

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