Incident Response Guide
How to create a plan for responding to a cybersecurity attack
What is the best way to avoid having a cyber attack turn into a full breach? Prepare in advance. After experiencing a breach, organizations often realize they could have avoided a lot of cost, pain, and disruption if only they’d had an effective incident response plan in place. This guide is intended to help you define the framework for cybersecurity incident response planning that gives you the best chance at thwarting an adversary. These recommendations are based on the real-world experiences of the Sophos Managed Threat Response and Sophos Rapid Response teams, who have tens of thousands of hours of experience when it comes to dealing with cyber attacks.
Cybersecurity incident response plan
There are 10 main steps to an effective incident response plan.
- Determine key stakeholders
- Identify critical assets
- Run table-top exercises
- Deploy protection tools
- Ensure maximum visibility
- Implement access control
- Invest in investigation tools
- Establish response actions
- Conduct awareness training
- Hire a managed security service
1. Determine Key Stakeholders
Properly planning for a potential incident is not the sole responsibility of your security team. In fact, an incident will likely impact almost every department in your organization, especially if the incident turns into a full-scale breach. To properly coordinate a response, you must first determine who should be involved. This often includes representation from senior management, security, IT, legal, and public relations.Knowing who should be at the table and involved in your organization’s planning exercises is something that should be determined in advance. Additionally, a method of communication needs to be established to ensure a quick response. This should take into account the possibility that your normal channels of communication (i.e. corporate email) may be impacted by an incident.
2. Identify Critical Assets
To determine the scope and impact of an attack, your organization first needs to identify its highest priority assets. Mapping out your highest priority assets will not only help you determine your protection strategy but will make it much easier to determine the scope and impact of an attack. Additionally, by identifying these in advance, your incident response team will be able to focus on the most critical assets during an attack, minimizing disruption to the business.
3. Run Tabletop Exercises
Incident response is like many other disciplines – practice makes perfect. While it is difficult to fully replicate the intense pressure your team will experience during a potential breach, practice exercises ensure a more tightly coordinated and effective response when a real situation occurs. It is important to not only run technical tabletop exercises (often as part of a red team drill), but also broader exercises that include the various business stakeholders previously identified. Tabletop exercises should test your organizational responses to a variety of potential incident response scenarios. Each of these scenarios might also include stakeholders beyond the immediate technical team. Your organization should determine in advance who needs to be informed when an attack is detected, even if was successfully defended.Common incident response scenarios include:
• Active adversary detected within your network: In these scenarios, it is critical that the response team determines how an attacker was able to infiltrate your environment, what tools and techniques they used, what was targeted, and if they have established persistence. This information will help determine the proper course of action to neutralize the attack. While it might seem obvious that you would immediately eject the adversary from the environment, some security teams choose to wait and observe the attacker to gain important intelligence in order to determine what they are trying to achieve and what methods they are using to achieve them.
• Successful data breach: If a successful data breach is detected, your team should be able to determine what was exfiltrated and how. This will then inform the proper response, including the potential need to consider the impact on compliance and regulatory policies, if customers need to be contacted, and potential legal or law enforcement involvement.
• Successful ransomware attack: If critical data and systems are encrypted, your team should follow a plan to recover such losses as quickly as possible. This should include a process to restore systems from backups. To ensure the attack won’t be repeated as soon as you’re back online, the team should investigate if the adversary’s access has been cut off. Additionally, your broader organization should determine if it would be willing to pay a ransom in extreme situations and, if so, how much it would be willing to spend.
• High-priority system compromised: When a high-priority system is compromised, your organization may not be able to conduct business normally. In addition to all the steps needed as part of an incident response plan, your organization also needs to consider establishing a business recovery plan to ensure minimal disruption in a scenario such as this.
4. Deploy Protection Tools
The best way to deal with an incident is to protect against it in the first place. Ensure your organization has the appropriate endpoint, network, server, cloud, mobile, and email protection available.
5. Ensure You Have Maximum Visibility
Without the proper visibility into what is happening during an attack, your organization will struggle to respond appropriately. Before an attack occurs, IT and security teams should ensure they have the ability to understand the scope and impact of an attack, including determining adversary entry points and points of persistence. Proper visibility includes collecting log data, with a focus on endpoint and network data. Since many attacks take days or weeks to discover, it is important that you have historical data going back for days or weeks (even months) to investigate. Additionally, ensure such data is backed up so it can be accessed during an active incident.
6. Implement Access Control
Attackers can leverage weak access control to infiltrate your organization’s defenses and escalate privileges. Regularly ensure that you have the proper controls in place to establish access control. This includes, but is not limited to, deploying multi-factor authentication, limiting admin privileges to as few accounts as possible (following the Principle of Least Privilege), changing default passwords, and reducing the amount of access points you need to monitor.
7. Invest In Investigation Tools
In addition to ensuring you have the necessary visibility, your organization should invest in tools that provide necessary context during an investigation. Some of the most common tools used for incident response include endpoint detection and response (EDR) or extended detection and response (XDR), which allow you to hunt across your environment to detect indicators of compromise (IOCs) and indicators of attack (IOA). EDR tools help analysts pinpoint which assets have been compromised, which in turn helps determine the impact and scope of an attack. The more data that is collected – from the endpoints and beyond – the more context is available during investigation. Having broader visibility will allow your team to not only determine what the attackers targeted but how they gained entry into the environment and if they still have the ability to access it again. In addition to EDR tools, advanced security teams might also deploy a security orchestration, automation, and response (SOAR) solution that aids in response workflows.
8. Establish Response Actions
Detecting an attack is only part of the process. In order to properly respond to an attack, your IT and security teams need to ensure they have the ability to conduct a wide range of remedial actions to disrupt and neutralize an attacker. Response actions include, but are not limited to:
- Isolating affected hosts
- Blocking malicious files, processes, and programs
- Blocking command and control (C2) and malicious website activity
- Freezing compromised accounts and cutting off access to attackers
- Cleaning up adversary artifacts and tools
- Closing entry points and areas of persistence leveraged by attackers (internal and third-party)
- Adjusting configurations (threat policies, enabling endpoint security and EDR on unprotected devices, adjusting exclusions, etc.)
- Restoring impacted assets via offline backups
9. Conduct Awareness Training
While no training program will ever be 100% effective against a determined adversary, education programs (i.e. phishing awareness) help reduce your risk level and limit the number of alerts your team needs to respond to. Using tools to simulate phishing attacks provides a safe way for your staff to experience (and potentially fall victim to) a phish, enrolling those that fail into training, as well as identifying risky user groups who may require additional training.
10. Hire A Managed Security Service
Many organizations are not equipped to handle incidents on their own. Swift and effective response requires experienced security operators. To ensure you can properly respond, consider working with an outside resource such as a managed detection and response (MDR) provider. MDR providers offer 24/7 threat hunting, investigation, and incident response delivered as a managed service. MDR services not only help your organization respond to incidents before they become breaches but also work to reduce the likelihood of an incident in the first place. MDR services are becoming very popular: according to Gartner*, by 2025, 50% of organizations will be using MDR services (this is up from less than 5% in 2019). Data forensic incident response (DFIR) services are occasionally also retained after an incident to collect evidence to support a legal or insurance claim.
When a cybersecurity incident strikes, time is of the essence. Having a well-prepared, well-understood response plan that all key parties can immediately put into action will dramatically reduce the impact of an attack on your organization.