One often overlooked aspect in the aftermath of a breach is the meticulous examination of firewall rule histories. These records not only reveal how an attacker gained access but can illuminate the path they took within an organization’s network.

When a breach occurs, the immediate response typically focuses on containment and mitigation. However, organizations need to understand the entry point, tools used and the attacker’s reach within the network to avoid leaving their systems vulnerable to similar attacks in the future. These histories can also help an organization gain a deeper understanding of a risky process that may have caused the breach, making it easy to improve or replace said process in the future.

Firewall and security policy rule histories serve as a timestamped log of all rule changes, enabling security teams to pinpoint exactly when and through which rule the breach occurred. This forensic capability is invaluable for determining the initial attack vector, whether it was through a misconfigured rule, an outdated policy or an exploited vulnerability.

Expediting Investigations

In the heat of a breach response, identifying recent changes to firewall rules can significantly speed up the investigation process.

Attackers often attempt to obfuscate their activities by altering rules to maintain access or to create additional openings for future exploitation. By scrutinizing firewall rule histories, security teams can quickly detect unauthorized or suspicious changes, allowing them to promptly revert to a secure state and close off potential avenues of attack.

Without accurate, real-time visibility into firewall rules, and a way to apply automation to the review and discovery of changes, this approach wouldn’t be as useful to investigators working against the clock to identify and close off any entry points and exploits.

Swift and Informed Actions

Now armed with the knowledge of how the breach occurred—as well as the specific rules that were manipulated – organizations can take immediate, decisive action to reinforce their defenses and prevent further exploits.

In many instances, security teams find themselves in a race against other attackers and nefarious actors, as once word gets spread around about an exploit or a vulnerable company, several individuals and groups try to gain access.

The actions that firewall rule knowledge gives security teams include the ability to modify rules to block the identified access points, ensuring no copycat breaches are conducted. Security teams often then update policies as a whole across the organization, to establish and enforce stricter security measures that would prevent similar attacks from being attempted.

Another tool security teams often implement is to then add additional layers of protection to their environment that are levels stronger than what was in place before. While it may seem like overkill to some, the idea is to make it so difficult to attempt even the smallest attack that they are left alone by attackers for a long time.

Analyzing the Root Cause

In the security industry, there are unfortunately many opportunities for organizational learning and improvement after a breach or an attack, regardless of whether they were successful or stopped right away.

Beyond the containment and security enhancement steps, firewall rule histories are also necessary to create a comprehensive post-mortem analysis of the breach’s scope and root cause.

One of the greatest takeaways from a firewall rule analysis is the insight into a network segmentation weakness or access control mechanism that needs to be addressed to prevent similar attacks from being successful in the future.

Understanding the lateral movement of attackers within the network helps in assessing the full extent of compromised systems or data. Rule histories can show security teams whether an attack was conducted quickly, as soon as an attacker gained access; or if it was a slow, methodical process where adjustments were made over time to secure maximum impact when finally set into motion.

Security teams can use firewall histories to identify recurring patterns, trends, or systemic vulnerabilities beyond those that lie on the surface. Without full visibility into rules and changes over time, organizations would be unable to refine their security strategies, update protocols, and proactively bolster their defenses.

Following Best Practices

Security organizations should adopt several best practices to harness the full potential of firewall rule histories. These include:

• Continuous Monitoring: Implement real-time monitoring of firewall rule changes to detect anomalies promptly. Weekly or monthly recaps of changes – even those seemingly approved – are far too long to be able to identify and react to an unauthorized or suspicious change.
• Automated Alerts: Similar to any task by a modern security team, automation is critical to having timely information and making a rapid response. Teams need to be sure to move beyond default settings and configure alerts so that unauthorized rule modifications or suspicious requests and adjustments are proactively brought to them.
• Documentation: It’s always a good practice to create and retain detailed documentation of rule changes, incidents, and remediation actions. Documentation is far too often seen as a time-consuming and wasteful task; that is, until an issue and security teams is scrambling to respond and mitigate an issue find that nothing has been updated.
• Regular Audits: Conduct periodic audits of firewall configurations and rule histories to ensure compliance and identify potential risks. This is important, even in instances where potential issues are proactively brought before security teams. Attackers are good at what they do, and audits help ensure nothing is missed, or that a temporary change isn’t left open and forgotten.

Firewall rule histories are a critical tool for security teams to use, both reactively to understand and respond to an issue; and proactively to give them the ability to improve and expand protections to ensure there isn’t a next time.

Attackers will continue won’t as long as there is a potential profit from an attack, but by leveraging firewall rule information, organizations cannot only enhance their resilience to cyberattacks but also create a culture of continuous improvement—something that’s critical for a modern security team and an organization in general.