Defensible Security Posture – Part 2

Defensible Security Posture – Part 2

Defensible Security Posture – Part 1

How can you leverage the Defensible Actions Matrix? A defensible actions matrix defines processes and procedures that can impact an attacker’s capability at various stages of the cyber kill chain.

Defensible Posture - Part 2

Cyber Kill Chain

In Defensible Security Posture – Part 1 we introduced the concept of the Cyber Kill Chain. As a recap, a “kill chain” describes the progression an attacker follows when planning and executing an attack against a target. Understanding the signature of an APT helps align defensive capabilities, i.e., to identify security controls and actions that can be implemented or improved to detect, deny, and contain an attack scenario.

Cyber Kill Chain

The APT Signature and Cyber Kill Chain

A complex incident may involve multiple kill chains with different objectives that map to various phases of the attack. For example, reconnaissance is performed to assess target feasibility to develop an attack plan. Attackers may also perform further reconnaissance after gaining an initial footprint into the internal network to revise strategy for lateral movement and persistence.

Defensible Actions Matrix

In this Defensible Security Posture – Part 2 blog we provide a case study that makes use of the Defensible Actions Matrix and offers some defensive practical best-practices. The basic idea of a Defensible Security Posture is that you aren’t striving for an absolute, but rather for a position (or posture) that is able to be defended even when it’s infiltrated. Common factors associated with APT attacks include the following:

  • Sudden increases in network traffic, outbound transfers
  • Unusual patterns of activity, such as large transfers of data outside normal office hours or to unusual locations
  • Repeated queries to dynamic DNS names
  • Unusual searches of directories and files of interest to an attacker, e.g., searches of source code repositories
  • Unrecognized, large outbound files that have been compressed, encrypted password-protected
  • Detection of communications to/from bogus IP addresses
  • External accesses that do not use local proxies or requests containing API calls
  • Unexplained changes in the configurations of platforms, routers or firewalls
  • Increased volume of IDS events/alerts

The more detailed Detection Framework, presented in APT Detection Framework is used to analyze the potential attack scenarios based upon a threat/risk profile to more definitively identify the above factors, as well as any detection gaps while the Defensible Actions Matrix summarizes it based on actions/controls.

The following example depicts a sample actions matrix using the actions of detect, deny, disrupt, degrade [optional], deceive [optional], and contain. Documenting the capabilities defenders can employ in this matrix as a worksheet enables organizations to quickly assess their Defensible Security Posture as well as identify any gaps or needed compensating controls.

Kill Chain Actions 2

Example Defensible Actions Matrix

Evolving Industry Best-Practices

In order to provide a foundation for the Defensible Actions Matrix we offer a sampling of defensive APT-aligned practical best-practices as an example. These will be expanded upon as a more complete APT Best-Practices framework and evolution in future blogs.

Industry Best Practices

Organizations should use a comprehensive programmatic approach, no one single technology will stop advanced attacks, even products specifically targeted at advanced forms of attack. Ongoing integration and sharing of security intelligence among disparate security
technologies and other external organizations should be a security program goal (see: APT Threat Analytics).

As such, organizations should review existing technologies and increasingly utilize advanced features in the latest products or services to keep up with changes in the threat landscape. This should be performed with the mindset of integrating and unifying security processes between each technology so that effective coordinated response to threats is possible and the detection and reduction of breach events is the result.

Security Governance

Social Media and Information Sharing: Attackers often leverage publicly available information on websites and social media to find information about an organization that can be useful in planning an attack. Information sharing and social media policies should define how material should be handled and exposed via public channels.

Configuration Management: Configuration standards define templates to consistently configure applications and systems based on role, hardening them, removing un-necessary services and, eliminating defaults. Define processes that are enforced with change control for infrastructure integrity to limit the ability of attackers to exploit infrastructure to deliver malicious software to targeted systems.

Privileged Access Management: Organizations face significant security exposure in the course of routine IT operations. For example, dozens of system administrators may share passwords for privileged accounts on thousands of devices. When system administrators move on, the passwords they used during their work often remain unchanged, leaving organizations vulnerable to attack by former employees and contractors.

Organizations should grant user and system accounts leveraging role-based access the least amount of privilege needed to perform the job. Processes to create, audit, and remove accounts and access levels should be well-defined.

Shared Service Accounts: Organizations should ensure that service accounts, including default credentials provided with third-party software, are properly secured with defaults removed and provided only to those who need them to perform their job function.

Database Account Security: Organizations should manage and audit database accounts as part of a larger account management process. This includes ensuring that accounts are only  granted the necessary level of access. Many organizations do not fully leverage the security built-in to databases and DBAs often use default admin accounts and users have full admin rights.

Two-factor Authentication: Two-factor authentication mechanisms is increasingly mandatory for networks or zones with critical data and/or servers. It can reduce the effectiveness of password stealing and cracking attempts.

Network Security Components

Threat Intelligence: A threat intelligence capability leveraging internal and/or external sourced visibility can provide an indication that threat actors are focusing on specific types of attacks and indicators to detect these attacks. For more information see APT Threat Analytics.

Network Zones / Segmentation: Limiting and intelligently managing communications between services and systems on an organizations network helps contain an infection or compromise to keep malware or a persistent threat from running rampant. Ensure proper zoning and segmentation is performed in your internal network environment not just the DMZ and that proper firewall logging and inspection is performed between high- and low-security segments. Treat every system as untrusted. For more information see Adaptive Zone Defense blog.

Advanced Threat Protection: Evaluate and deploy a network-based advanced threat detection/prevention technology to reduce the potential impact of zero-day malware and other targeted attacks. Review existing advanced threat detection/prevention technology and ensure that the prevention capabilities are validated, tested and fully leveraged.

Context-Awareness: Evaluate and leverage context-aware security capabilities of security platform providers. Security platforms must become context-aware — identity, application, content, location, geo-location and so on — in order to make better information security decisions regarding APTs.

Firewall Rules/ACLs: Review and, if necessary, adjust ingress network firewall rules on a regular basis in order to ensure only critical inbound services are permitted to enter the network. This also includes geographical blocking or filtering at the country level where possible based on business need. For more information on Firewall Rule Lifecycle Management, see Security Program Best-Practices – Part 5.

Egress / Outbound Filtering: Egress filtering enables a managed perimeter with a focus on well-defined outbound policy. It declares the acceptable protocols and destination hosts for communication with internal systems, with a focus on any systems with critical or regulatory data, such as PII, ePHI, PCI and so on.

Network activity associated with remote control can be identified, contained, disrupted through the analysis of outbound network traffic implemented through open source software tools.

Remote Access / VPN: Implement internal inspection devices, such as intrusion prevention system (IPS) and network behavior analysis (NBA) technologies between any VPN termination device and the internal network environment so that attacks or behaviors can be discovered or prevented within the remote access network infrastructure.

DNS Sinkholes: A DNS-based sinkhole monitors for name resolution attempts of known malicious or suspicious domains. The resolution response is modified to point to an internal sinkhole server where the malicious or suspicious traffic is routed for further analysis and containment. In addition block “uncategorized” web sites at proxies, employ split‐DNS and split‐routing where possible.

Network IPS: Network intrusion prevention systems (IPS) can actively block network traffic matching patterns associated with malware command-and-control (C2) communication and data exfiltration. Review NG-IPS features and ensure it provides host and traffic anomaly detection (for example, using processing NetFlow data) and has capabilities to prevent or at minimum detect and alert on the anomalous traffic exiting through your perimeter devices.

Network IDS: A network intrusion detection system (IDS) can identify traffic patterns matching network-based scanning, malware C2 mechanisms, and data exfiltration. For more information see: APT Detection Indicators.

Network Security Monitoring: Validate that monitoring controls are in place and appropriate levels of logging are performed off-device in centralized log servers. Deploy security information management systems so that attacks can be detected or analyzed through additional analysis or correlation of incoming events.

Make sure that network visibility extends into virtualized environments either by tapping internal virtual switch traffic out for external inspection or by virtualizing IPS capabilities and running directly within the virtualized environment.

Form a Security Operations Center (SOC) or designate specific individuals to operate as a security operations center in order to properly monitor and respond as well as perform initial triage status for security events. When suspicious anomalies or alerts are received by the security operations center, invoke the incident response process.

Incident Response: Organizations should have a response plan for handling incidents as well as periodically review and test the plan. For more information on response readiness and preparedness please see APT Response Strategy.

Application Security

Web Application Firewalls: Review Web application firewall configuration and implement vendor-recommended prevention settings. Prefer application firewalls that have the capability to share intelligence via reputation feeds, offer fraud detection services, and offer the capability to perform browser and endpoint security and spyware infection assessment.

Endpoint Protection: Host-based malware protection solutions including antivirus software, host intrusion prevention systems, and advanced malware protection solutions help identify, alert and block malicious software.

File Integrity Monitoring: File integrity monitoring involves monitoring system files for unauthorized changes and is often deployed as part of a larger software change management process.

Application Whitelisting: Application whitelisting defines a limited set of software that can be run on a system. Application whitelisting requires continual management of the list of allowed software to keep up with application and operating system updates.

Data Loss Prevention (DLP): Data loss prevention solutions use information tagging, packet inspection, and network monitoring to identify the potential movement of sensitive data outside the network. In addition, organizations can implement policies to manage the use of removable storage devices such as USB to limit these devices being used to steal sensitive information.

Security controls can have various impacts based on their purpose and implementation. Ultimately, the goals of a security control is to detect malicious activity, deny the malicious activity access to targeted assets, disrupt malicious activity that is actively in progress, or contain malicious activity to an area where damage can be mitigated.

The matrix illustrated below provides a partial example worksheet, applying the above best-practices and organizes the controls according to whether their primary goal is to detect, deny, disrupt, or contain.

Defensible Actions Matrix 2

Best-Practice Defensible Actions Matrix Use Case [Partial]


Recent incidents clearly demonstrate that cybercriminals can conduct operations that involve intrusion, lateral movement, and data exfiltration in complex networks secured to current best-practices. Attackers can adapt their attack techniques to the unique circumstances of targeted environment.

This level of resourcefulness points to the realization that current best-practices and regulatory compliance are a necessary minimum baseline but are not sufficient alone. Today there is an increasing need for organizations to progressively evolve and advance from current security posture to a more defensible and advanced program with visibility, validation and, vigilance.

Our solution, and the prime basis for this site, is to adopt a security architectural and design foundation approach that compartmentalizes breaches into small zones on networks and on endpoints. To strategically leverage the Adaptive Zone Defense blog to develop an innovative architecture with well-organized applications and services, managed communications and – good visibility to flows and logs that can actually detect the cyber kill chain activity and stop the breach.

It requires an ongoing lifecycle process to take the legacy, rapidly deployed and the chaotic infrastructure on the edge (innovation) and consolidate it into the core foundation based on the architecture/design blueprint, while continually evolving the blueprint based on new business requirements, technology solutions and, regulatory requirements, for more information see: Adaptive Security Lifecycle

Coming Soon

In this series we will discuss advanced APT-focused best-practices that enable organizations to take their security to the next level and build from Basic to Augmented through to APT-specific Countermeasures to Advanced Security depending upon various factors including assets and threat/risk profile.

APT Best Practices

Evolution Lifecycle using Security Best-Practices

In the upcoming APT Operational Maturity and APT Intelligent Operations blogs we will also discuss the need for a continuously evolving next-generation SIEM, risk management processes and, network behavior anomaly detection that enable organizations to take security operations and situational awareness to the next level, depending upon various factors including threat/risk profile.

Intelligent Operations Evolution


This Defensive Security Posture – Part 2 blog is also a part of the APT Strategy Series and Security Architecture Series. For a complete listing of all NigeSecurityGuy blogs see the Security Series Master Index.

Thanks for your interest!

Nige the Security Guy.

Defensible Security Posture

Defensible Security Posture – Part 1

Defensible Security Posture – Part 2

The purveyors of Fear, Uncertainty and Doubt (FUD) assert that preventing today’s advanced threats is unrealistic, internal compromise is inevitable and – that FUD factor is reinforced by more and more reports of malware and advanced attacks penetrating insufficient security controls. However, it’s not all doom and gloom. Although the experts concede that stopping 100% of attacks is a technical impossibility, there are ways for organizations to avoid becoming the next devastated victim.


Unfortunately ‘secure‘ is still the target of many CISOs and company leadership. From painful experience many security practitioners collectively know that ‘secure‘ is a mythical goal and doesn’t actually exist. The leap in logic proposed by this blog is that we move to something that’s ‘defensible‘.

The basic idea of a Defensible Security Posture is that you aren’t striving for an absolute, but rather for a position (or posture) that is able to be defended even when it’s infiltrated. The analogy that I like to use is the human immune system since security and advanced attacks are organic in nature and can come from various sources of infection. There are a few basic things we need to understand:

  1. Defensible does not mean secure
  2. There are more things to defend than there are resources to defend
  3. Sometimes your defenses can become your weakness
  4. Defensibility requires deep understanding of what critical assets you’re defending
  5. Defensibility focuses on what, why, how, when and from whom

Advanced Persistent Threats

The US National Institute of Standards and Technology (NIST) defines that an APT is:

An adversary that possesses sophisticated levels of expertise and significant resources which allow it to create opportunities to achieve its objectives by using multiple attack vectors (e.g., cyber, physical, and deception). These objectives typically include establishing and extending footholds within the information technology infrastructure of the targeted organizations for purposes of exfiltrating information, undermining or impeding critical aspects of a mission, program, or organization; or positioning itself to carry out these objectives in the future. The advanced persistent threat: (i) pursues its objectives repeatedly over an extended period of time; (ii) adapts to defenders’ efforts to resist it; and (iii) is determined to maintain the level of interaction needed to execute its objectives.

Attacks from APTs are growing in scope,  increasing in frequency and, improving in effectiveness – to establish an insider base camp and cover tracks. Current strategies are not well-suited to mitigating prolonged and determined attackers leveraging a growing collection of stealthy techniques. The traditional perimeter and prevention response to threats is no longer realistic. Organizational resources need to shift the focus instead onto – Detection, Containment, Eradication and Recovery.

Defensible Logo

There is no silver bullet or single solution. Most organizations continue to focus on defending against zero-day exploits by relying on commercial security products to block bad sites and software and by patching systems to correct vulnerabilities in installed software. While these approaches are effective against some threats, they fail to stop the advanced attacks and provide no knowledge of what an adversary does once the network is penetrated.

APT attackers continually demonstrate their capability to compromise systems by using social engineering techniques, customized malware, and zero-day exploits that intrusion detection, anti-virus and patching cannot always detect or mitigate. Responses to APT intrusions require an evolution in analysis, process, visibility and technology. This blog describes an intelligence-driven, threat-focused approach.

Intelligence-driven Network Defense

Organizations may use a number of active techniques to detect attacks that can circumvent passive defenses. One approach uses honeypots to attract adversaries and look for patterns of behavior. Organizations may employ a number of active defense techniques within their own enterprises to detect and track adversaries as they explore networks. If a honeypot is set up with a number of different types of documents, organizations can watch to see which documents the adversary chooses to try to ex-filtrate.

Intelligence-driven Network Defense is a risk management strategy that addresses the threat component of risk, incorporating analysis of adversaries, their capabilities, objectives, doctrine and limitations. This is necessarily a continuous process, leveraging indicators to discover new activity. It requires a new understanding of the intrusions themselves, not as singular events, but rather as phased progression.

The benefit of Intelligence-driven Network Defense is a more resilient security posture. After all, APT attackers are persistent and attempt intrusion after intrusion, adjusting their operations based on the success or failure of each attempt. Once a compromise is achieved then the APT attacker deploys backdoors for contingency and covers any tracks.

The Signature of an APT

In any Advanced Persistent Threat (APT) attack there are typically a pre-defined set of phases that act as a signature, as follows:

APT Evolution

The importance is not that this is a linear flow – some phases may occur in parallel, and the order of earlier phases can be interchanged – but rather how far along an adversary has progressed in his or her attack, the corresponding damage, and investigation that must be performed.

APT Attack Kill Chain 2

  • Reconnaissance – Research, identification and selection of targets, often represented as crawling Internet websites such as social networks, organizational conferences and mailing lists for email addresses, social relationships, or information on specific technologies.
  • Weaponization – Coupling a remote access trojan with an exploit into a deliverable payload. Increasingly, application data files such as PDFs or Microsoft Office documents serve as the weaponized deliverable.
  • Delivery – Transmission of the weapon to the targeted environment via, for example, email attachments, websites, and USB removable media.
  • Exploitation – After payload delivery to victim host, exploitation triggers intruders’ code. Exploitation targets an application or operating system vulnerability or leverages an operating system feature that auto-executes code.
  • Installation – Installation of a remote access trojan or backdoor on the victim system allows the adversary to maintain persistence inside the environment.
  • Command and Control – APT malware typically establishes remote command and control channels so that intruders have “hands on the keyboard” access inside the target environment.
  • Actions on Targets – Typically the prime objective is data exfiltration which involves collecting, encrypting and extracting information from the victim environment. Intruders may only seek access to victim box for use as a jump point to compromise additional systems and move laterally inside the network or attack other partner organizations.

Actionable Intelligence and the Intrusion Kill Chain

Cyber ‘kill chain’ methodology is the latest in a series of security strategies, targeted especially at APTs that are based on more of a proactive and visible model of real-time network monitoring, analysis, and mitigation. The formal concept of cyber ‘kill chain’ methodology was first developed by a group of scientists at Lockheed Martin in a paper titled, “Intelligence-Driven Computer Network Defense Informed by Analysis of Adversary Campaigns and Intrusion Kill Chains“.

The intrusion kill chain becomes a model for actionable intelligence where practitioners align organizational defensive capabilities to the specific processes an adversary undertakes to target that organization. The end goal of this is to analyze the data for patterns of attack methods, behaviors of distinct hostile actors, and other indicators which can inform the development of unique responses. Fundamentally, this approach is the essence of Intelligence-driven Network Defense security posture basing security decisions and measurements on a keen understanding of the adversary.

Defensible Actions Matrix

The following is an example of a table that depicts a course of action matrix using the actions of detect, deny, disrupt, degrade, deceive, and contain. Documenting the capabilities defenders can employ in this matrix as a tool enables the reader to assess their Defensible Security Posture as well as identify any gaps or needed compensating controls. The matrix includes traditional systems like network intrusion detection systems (NIDS) and Firewall access control lists (ACL), system hardening best practices like audit logging, but also vigilant users themselves who can detect suspicious activity.

Kill Chain Actions 2

Intelligence-driven Network Defense is a necessity in light of advanced persistent threats. As conventional, vulnerability-focused processes are insufficient, understanding the threat itself, its intent, capability, doctrine, and patterns of operation is required to establish resilience. The intrusion kill chain provides a structure to analyze intrusions, identify indicators and drive defensive courses of actions. This model prioritizes investment for capability gaps, and serves as a framework to measure the effectiveness of the defenders’ actions. When defenders consider the threat component of risk to build resilience against APTs, they can turn the persistence of these actors into a liability, decreasing the adversary’s likelihood of success with each intrusion attempt.

Evolving Towards a Defensive Posture

If your organization does not already have visibility with proactive monitoring built into your environment this may seem like a major challenge. Implementing an Intelligence-driven Network Defense with a Cyber Kill Chain should be based initially on a prototype then iterate approach to evolve in capability and sophistication. Start with a basic framework that you can comfortably build and operate then make progress from there.

Cyber Kill Chain

Perform a Security Health Check with a focus on the organization’s web presence and external perimeter to see what information it could give an attacker – or leverage a 3rd party professional. Implement layered security to decrease the possibility that threats will slip through unnoticed. Create a policy for dealing with malware events. Educate staff about what to do with unexpected, suspicious emails and attachments.

With each step taken, you’ll get more information about your environment. And the more information you have, the more likely you will be able to identify anomalous behavior.

Next Steps

In Defensible Security Posture – Part 2 we discuss a case study that leverages the Defensible Actions Matrix and provides some recommended APT-focused best-practices.

The Defensible Security Posture series using an Intelligence-driven Network Defense will be built upon in future blogs. In the APT Operational Maturity and APT Intelligent Operations blogs we will discuss the need for a continuously evolving next-generation SIEM, risk management processes and, network behavior anomaly detection that enable organizations to take security operations and situational awareness to the next level, depending upon various factors including threat/risk profile.

The defensible architecture foundation uses Adaptive Zone Defense to segment critical assets from general-purpose infrastructure to enable containment that includes Application Architecture Taxonomy to discusses the analysis, placement, policy and, controls for assets based upon classification and risk. There will also be a blog that takes a deeper dive in Risk Management Practices.

Thanks for your interest!

Nige the Security Guy.