Adversaries may disable or modify a firewall within a cloud environment to bypass controls that limit access to cloud resources. Cloud firewalls are separate from system firewalls that are described in Disable or Modify System Firewall.
Cloud environments typically utilize restrictive security groups and firewall rules that only allow network activity from trusted IP addresses via expected ports and protocols. An adversary with appropriate permissions may introduce new firewall rules or policies to allow access into a victim cloud environment and/or move laterally from the cloud control plane to the data plane. For example, an adversary may use a script or utility that creates new ingress rules in existing security groups (or creates new security groups entirely) to allow any TCP/IP connectivity to a cloud-hosted instance.(Citation: Palo Alto Unit 42 Compromised Cloud Compute Credentials 2022) They may also remove networking limitations to support traffic associated with malicious activity (such as cryptomining).(Citation: Expel IO Evil in AWS)(Citation: Palo Alto Unit 42 Compromised Cloud Compute Credentials 2022)
Modifying or disabling a cloud firewall may enable adversary C2 communications, lateral movement, and/or data exfiltration that would otherwise not be allowed. It may also be used to open up resources for Brute Force or Endpoint Denial of Service.
Detection Strategy for Disable or Modify Cloud Firewall
Audit: Auditing is the process of recording activity and systematically reviewing and analyzing the activity and system configurations. The primary purpose of auditing is to detect anomalies and identify potential threats or weaknesses in the environment. Proper auditing configurations can also help to meet compliance requirements. The process of auditing encompasses regular analysis of user behaviors and system logs in support of proactive security measures.
Auditing is applicable to all systems used within an organization, from the front door of a building to accessing a file on a fileserver. It is considered more critical for regulated industries such as, healthcare, finance and government where compliance requirements demand stringent tracking of user and system activates.This mitigation can be implemented through the following measures:
System Audit:
Permission Audits:
Software Audits:
Configuration Audits:
Network Audits:
User Account Management: User Account Management involves implementing and enforcing policies for the lifecycle of user accounts, including creation, modification, and deactivation. Proper account management reduces the attack surface by limiting unauthorized access, managing account privileges, and ensuring accounts are used according to organizational policies. This mitigation can be implemented through the following measures:
Enforcing the Principle of Least Privilege
Implementing Strong Password Policies
Managing Dormant and Orphaned Accounts
Account Lockout Policies
Multi-Factor Authentication (MFA) for High-Risk Accounts
Restricting Interactive Logins
Tools for Implementation
Built-in Tools:
Identity and Access Management (IAM) Tools:
Privileged Account Management (PAM):