Reacting to security incidents can be an overwhelming and difficult task if you are not prepared. This chapter
covers several best practices, techniques and tips for use when reacting to security incidents. Without successful identification, classification and traceback, you will never be able to effectively react to any security event. Be sure to check out our network security topics page for advice on all of your security concerns.
The steps you take when reacting to security incidents depend on the type of threat you are mitigating. For example, if you are mitigating a distributed denial-of-service (DDoS) attack, you will probably not take the same steps as when reacting to a theft of information where the attacker does not make that much noise on the network. However, when reacting to any security incident, time is one of the most critical factors.
It is extremely important to have well-defined incident handling policies in place. In Chapter 2, "Preparation Phase," you learned that without defined policies and procedures for mitigation, you can put yourself in a difficult position when a security outbreak or event occurs. Following these policies or procedures is important.
These policies may be in the form of standalone documentation, or they may be incorporated into other documentation such as company security policies or disaster recovery plans. You may consider developing different procedures and response mechanisms when responding to a direct DDoS attack versus a worm outbreak, or when information has been stolen. Not all security incidents are the same, and you should make sure that the appropriate response procedures are in place.
You should try to create a security policy and be serious about covering all facets of security. Ideally, you should develop security policies in the preparation phase. Collaboration between support teams within your organization may be necessary when responding to security incidents. After you have successfully identified a security incident, classified it, and tracked it, you must notify the appropriate personnel. For example, if you are a member of the Information Security (InfoSec) or Security Operations (OpSec) team, you may need to involve administrators from separate parts of your organization. You may not have access to the affected device or may not be an expert on a specific application. This is why collaboration is so important.
The reason for setting up collaboration between support teams is to establish lines of communication and ensure that personnel understand the areas of responsibility and capability for each partner. In addition, you should provide a detailed description of the incidents technical aspects to your collaborative teams. This will aid in prompt acknowledgment and understanding of the problem. However, great care should be taken, because you do not want to distribute sensitive information unnecessarily.
You should also have adequate emergency procedures in place. In some cases, you may need to discuss issues and tasks within external teams. For example, suppose that you are a member of the OpSec group and you are trying to get information about a specific system that an external team controls. After several attempts, you have received no response. With the correct escalation procedures in place, the task of getting the right people involved becomes easier. Similarly, you should have emergency procedures when other teams try to engage your staff. The main goal of incident response is to restore control of the network and its systems and to limit the impact and damage. Many people say that, in some cases, shutting down affected systems or disconnecting the system from the network may the only practical solution. However, if you have the necessary tools in place, you may be able to quarantine and remediate such systems without unplugging them from the network. For example, you can use routing as a security mechanism and isolate systems within your network. You can use mechanisms such as remotely triggered blackholes (discussed later in this chapter) and in other cases put systems in quarantine segments so that you can patch them accordingly when security outbreaks occur.
Having a systematic approach for patch management is crucial. For instance, if you have a good system in place to provide security operating system and application patches as soon as they become available, your systems are far less likely to fall prey to major attacks. An updated security management system is not a top priority for many companies; however, attackers, worms, and malware do not wait for you to patch every system manually. More importantly, in the case of worm outbreaks, having a distributed patch management system can save you and your staff considerable time thereby saving your organization money.
It is important to create checklists of procedures to be followed during an incident. Documenting events as they happen is important. On most occasions, you may feel as if you do not have time to completely document events in detail during the incident. However, during the identification, classification, and traceback phases, you should gather as much information about the incident as possible. Attempt to answer the following questions:
- What type of incident are you experiencing?
- When did the attack occur (date and time)?
- Where did the attack occur?
- What systems were affected and compromised
These are some of the most fundamental questions that need to be answered. You may develop more specific questions on a case-by-case basis.
Another procedure that you must document is when to involve law enforcement. Incident response is probably one of the disciplines most affected by legal considerations because many incidents involve some sort of crime. Consequently, your organization might want to prosecute the attacker, and in this case, it must consider the legal implications of the incident. If legal implications are present, you must assist law enforcement in all aspects of their investigation. Different laws and regulations are covered in the next section.
Printed with permission from Cisco Press. Copyright 2007. End-to-End Network Security: Defense-in-Depth by Omar Santos. For more information about this title and other similar books, please visit www.ciscopress.com.