Skip to content

Modify Firewall

What: Modify Firewall

The "Modify Firewall" tactic refers to the manipulation or alteration of firewall settings by an adversary to bypass security measures, maintain access to a network, or enable unauthorized network activities. Firewalls are critical security devices or software that control incoming and outgoing network traffic based on predetermined security rules. Modifying these rules can significantly impact the security posture of an organization.

How: Techniques and Methods

  1. Access Gaining: Initially, the adversary needs administrative privileges to modify firewall settings. This can be achieved through various means such as exploiting system vulnerabilities, obtaining administrator credentials via phishing attacks, or using malware.

  2. Identifying Firewall Configuration: Once access is gained, the next step involves identifying the type of firewall (hardware-based or software-based) and its configuration settings. This might involve command-line queries (iptables -L on Linux), accessing configuration files, or using administrative tools provided by the firewall vendor.

  3. Modification Techniques:

  4. Rule Changes: Adding, removing, or altering firewall rules to allow/block specific traffic.

  5. Port Redirection: Redirecting traffic from one port to another to circumvent firewall rules designed for specific ports.

  6. Disabling Features: Turning off certain firewall functionalities like IDS/IPS (Intrusion Detection/Prevention Systems), logging mechanisms, or alert triggers.

  7. Automation of Changes: In sophisticated attacks, scripts or malware might be used to automate the modification of firewall settings to ensure persistent unauthorized access or repeated exploitation.

Where: Application Environments

  • Enterprise Networks: In corporate environments where firewalls protect internal networks from external threats.
  • Data Centers: Large-scale data centers utilize advanced firewalls to segment traffic and protect sensitive data.
  • Cloud Environments: Modification of cloud-based firewalls (like AWS Security Groups) which requires access to cloud management platforms.
  • Home Networks: Less common but possible in targeted attacks where home routers and firewalls are manipulated.

Why: Objectives Behind Modifications

  1. Maintain Persistence: By allowing backdoor communications through specific ports that are normally blocked.
  2. Facilitate Lateral Movement: Modifying internal firewall rules can help attackers move within a network undetected.
  3. Exfiltrate Data: Altering rules to allow outbound connections that facilitate data leakage without triggering security alerts.
  4. Deny Service: Disabling protective mechanisms can make it easier for attackers to perform denial-of-service attacks against other systems without interruption.
  5. Evade Detection and Analysis: Disabling logging features prevents the recording of malicious activity, thereby avoiding forensic analysis post-breach.

In conclusion, modifying firewall configurations is a powerful technique in an adversary’s arsenal because it directly impacts an organization’s ability to detect and respond to malicious activities within their networks. Understanding this tactic underscores the importance of robust management practices around critical security controls like firewalls including rigorous monitoring and auditing procedures ensuring any unauthorized changes are quickly detected and remediated.