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Cyber Incident Response Primer

Incident Response Cookbook C-TAG V04 May 2021.pdf
Incident Primer
Things go wrong in ICT systems, either accidentally, a wrong parameter or filename used or a deliberate act of maleficence, to cause harm to the system, such as an attack, often through the Internet which we now refer to as a Cyber Attack.
Modern computer networks and system, can be defended automatically to deal with the majority of low level attacks, where these attacks are mitigated and solved, they are referred to as events. Where an attack or event actually causes a physical outcome (System crash, malware infection etc.), that leads to an Incident. The overall monitoring systems for dealing with systems and networks is referred to as a SEIM (Security Event & Incident Monitoring) system.
Before you can do anything, you must ensure your network have a consistent and stable network time source This is a requirement for the PSN code of Connection, as without it you cannot normalise data of correlate logfiles. The NCSC Logging Made Easy [14] will help with some of this work. The NCSC produce other Incident Management information [15] that should be read and adhered to. You must have up to date detailed and accurate network diagrams [16] and systems documentation. There are plenty of drawing tools to help you do so [17]. Without neither you or an external Network response company will be able to help you, valuable time and resources will be wasted. The NCSC has a scheme (Certified Incident Response CIR) and list of trusted companies that can help [18]. The Scottish Government has also published a Cyber Resilience and Response Guide [19]. There is also a Scottish Government Cyber Playbook that can be downloaded and customised [20]. Asset registers are critical to success and will be the subject of a future C-TAG guide.
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Defining Incident Response
We’ve discussed events and what leads to an incident. When an incident happens, the first thing that needs to happened is to actually be aware of the attack. Some attacks can go undetected for months. This is why we ensure that systems are secure by design, this is the who purpose of Information Assurance and Risk Management. The only objective of Incident Response is to get to the make safe point, where the unwanted systems / network behaviour is stopped in its tracks. Once at make safe, the next and longer phase is Incident Recovery. The objective of the recovery phase itself is to get the system / network back to a stable state, that is how the network or system was at the point the incident happened. Incident recovery is not about improvement. Both Incident response and Incident recovery have clearly defined boundaries.
An incident can be thought of as a fast time resource intensive project. and if thought of as such, with a start, middle and end it becomes far easier to know when and incident is concluded. Open ended Incidents are not good practice and allow non-incident related issues to be introduced, causing complications and additional complexities.
Where to start?
There is an ISO standard for Incident response ISO 27035 [1] as with all standards, it details an approach and linked nicely with ISO 27001, ISO 27035 with it’s five stage approach;
  1. 1.
    Plan and prepare: establish an information security incident management policy, form an Incident Response Team etc.
  2. 2.
    Detection and reporting: someone has to spot and report “events” that might be or turn into incidents;
  3. 3.
    Assessment and decision: someone must assess the situation to determine whether it is in fact an incident;
  4. 4.
    Responses: contain, eradicate, recover from and forensically analyze the incident, where appropriate;
  5. 5.
    Lessons learnt: make systematic improvements to the organization’s management of information risks as a consequence of incidents experienced.
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Source: Ref [22]
The figure above shows the types of attack vectors, how the malicious code / data gets into the network / system.
There's also the American NIST Incident handling guide [2] NIST SP800-61 revision 2. This dates back to 2012, but does contain a lot of useful advice and guidance. For specific cloud related guidance the Cloud Security Alliance has an incident response guide [26].
The NIST approach discusses;
  • Preparation (Planning)
  • Detection and Analysis (Response)
  • Containment (Make safe)
  • Post-incident action (Recovery)
The Erez Dasa table above shows how these can map across to technologies in the cloud.
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Source: Ref [22]
Some very good examples of incident playbook (think of plans or recipes as we’re in a cook book), can be found here [3] the approach is very good. Whilst Forensics are out of scope for this paper, there is an excellent primer and source of information from SANS to be found here [4]. Sans also produces an incident handlers guide that can be found here [5].
We have discussed exercising, the MHCLG Pathfinder programme delivered a number of Cyber Exercises [6]. The NCSC have produced the Exercise in a box suite, that can be freely downloaded and contains all of the materials needed to plan and run a successful cyber exercise [7]. For really in depth guidance the Mitre Exercise planning guide is a comprehensive and authoritative guide [8].
Responding to Cyber incidents will always be different to what you’ve planned for. The idea of planning is more about trying to understand the decisions, line of communications and the team building experience. Plans make you think about scenarios, which can be exercised. All incidents will need resources. The FT produced a useful report “Surviving a Cyber Incident” containing a lot of sage advice [9]. For information, have a look at the Golden Hour Guide which is described in the Cyber Incident Framework [10] the paper also contains a number of useful case studies and other information.
The guide also discusses the NLAWARP / Silverthorn SIRO Risk framework © , with it’s six stages, mapping
  1. 1.
    Identify and map out key systems / services /suppliers
  2. 2.
    Identifying how we get assurance for key systems services / suppliers
  3. 3.
    Identifying Key Information Risks (to develop Key Risk Indicators (KRIs)
  4. 4.
    Articulating Information Risk Statements (Risk / Threat/ Vulnerability/Exploit)
5) Defining Risk Appetite [25] (Taking 1-4 above identifying assurance gaps).
6) Articulating a Risk Appetite (Using business language [User Stories] [23])
User stories are incredible powerful for Risk Management, Cyber Exercising and for testing assumptions. Risk Poker [24] is another useful way to articulate the risks.
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Source Isaca [23]
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Source: Figure 1 above and table below; Cyber Incidents: Uma, M. and Padmavathi Ganapathi. “A Survey on Various Cyber Attacks and their Classification.” I. J. Network Security 15 (2013): 390-396. Ref [21]
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Do not underestimate the amount of time a Cyber attack will take to resolve. As we said earlier the incident part only goes as far as “Making Safe”, (Containment). The hard works starts with the recovery phase. It could take weeks, months or years to completely get back to normal. You need to plan for that and have that as a “Planning Assumption”. The NCSC list some helpful context about planning assumptions in dealing with suppliers [11]. You need to undertake Horizon scanning [12] and a Risk Assessment with a Threat analysis, the UK space Agency has produced a useful Cyber Toolkit which explores these areas [13]. so that you can prioritise your planning assumptions.
Procuring help to recover from an incident (NE WARP Case study)
our objectives:
  • To have a ready-to-go incident response service to hand for whenever required
  • To have the option of annual readiness check in terms of required documentation etc. that would be requested by an incoming response service
  • procure up front and have on standby
  • procure at the time of need
  • use CCS (Crown Commercial Services) dynamic purchasing system for cyber which includes NCSC CIR (Cyber Incident Response) providers
  • conduct a local procurement
In the event of a critical incident requiring incident response it is likely emergency procurement would be possible. However, we’d still need to find and identify potential suppliers, explain our situation and what we think we need, enquire of their availability and costs.
Preferred route – CCS DPS
CCS DPS has minimum 10-day turnaround, clearly not appropriate for Incident Response at the time of need. NE WARP is looking to discuss with suppliers to agree to reduce this.
Buyers would need to follow the DPS buying process, complete necessary documents and be happy with the 'legal basis'- this would require procurement resource at the time of need - however templates etc could be developed. This is something that needs to be factored in to the planning assumptions.
3 Incident Playbook examples:
9 FT Guide to Cyber Incident Survival:
16 Network Diagrams blog:
18 NCSC Certified Incident Response Companies:
21 Catergorising Cyber Incidents: Uma, M. and Padmavathi Ganapathi. “A Survey on Various Cyber Attacks and their Classification.” I. J. Network Security 15 (2013): 390-396.