CISO AppSec Guide: Introduction
- 1 Introduction
- 1.1 Objectives
- 1.2 Target Audience
- 1.3 Executive Summary
Among application security stakeholders, Chief Information Security Officers (CISOs) are responsible for application security from governance, compliance and risk perspectives. This guide seeks to help CISOs manage application security programs according to CISO roles, responsibilities, perspectives and needs. Application security best practices and OWASP resources are referenced throughout this guide. OWASP is a non profit organization whose mission is "making application security visible and empowering application security stakeholders with the right information for managing application security risks".
This CISO guide is written to help CISOs that are responsible for managing application security programs from the information security and risk management perspectives. From the information security perspective, there is a need to protect the organization assets such as the citizen/client/customer sensitive data, the databases where this data is stored, the network infrastructure where the database servers reside and last but not least the applications and software used to access and process this data. Among the assets that CISOs seek to protect, besides business and user data there are also applications and software as a whole since these might provide business critical functions to customers that generate revenues for the organization. Examples include applications and software that provide customers with business services as well as applications and software that are sold as products to the clients. In the case when software application are considered information assets to protect. Since both directly or indirectly provide services to citizens/clients/customers, application security should receive a specific focus in human resources, training, processes, standards and tools. The scope of this guide is the security of software applications and the security of the related infrastructure such as the security of web servers, application servers and databases. This does not include other aspects of security that are not specifically related to the specific application, such as the security of the network infrastructure that supports the applications and constitutes a valued asset whose security properties such as confidentiality, integrity and availability need to be protected as well.
This guide helps CISOs manage application security risks by considering the exposure from emerging threats and compliance requirements. This guide helps:
- Make application security visible to CISOs
- Assure compliance of applications with security regulations for privacy, data protection and information security
- Prioritize vulnerability remediation based upon risk exposure to the business
- Provide guidance for building and managing application security processes
- Analyze cyber-threats against applications and identify countermeasures
- Institute application security training for developers and managers
- Measure and manage application security risks and processes
- Chief Information Security Officers (CISOs)
- Senior security management
- Senior technology management
The fact that applications ought to be considered company's assets is "per se" a good reason to put applications in scope for compliance with information security policies and standards. The impact of compliance with information security policies and standards for applications typically depends on the classification of the asset-data stored by the application, the type of exposure of the application to the users (e.g. internet, intranet, extranet) and the risk of the functionality that the application supports with the data (e.g. access to confidential data, transfer of money, payments, users administration etc). From information security perspective, applications should be in scope for organizations specific vulnerability assessments and application security requirements. The security validations and certifications of applications follow specific security requirements such as for the secure design, secure coding and secure operations. These are often part of the goals of application security standards. Therefore compliance is a critical aspect of application security and of CISOs responsibilities but not the only one.
Application security spans also other security domains that CISOs are responsible for. These can be summarized as (GRC) Governance, Risk and Compliance.
- From governance perspective CISOs are responsible to institute application security processes, roles and responsibilities to manage them and software security training and awareness for software developers such as defensive coding and vulnerability risk management for information security officers/managers.
- From the risk management perspective, the risks managed by the CISOs also include application security risks such as the risks of specific threats targeting applications that process confidential user data by seeking to exploit gaps in security controls as well as vulnerabilities in applications.
- Among CISOs security domains, compliance with regulations and security standards is often the one that gets the most attention from the organization's executive management. The aim of this guide, is to help CISOs fulfill compliance requirements as well as to use compliance requirements as one of the reasons for justifying investments in application security. For some organizations managing risks of security incidents such as credit card fraud, theft of personal identifiable information, theft of intellectual property and confidential data is what gets most of executive management attention especially when the organization has been impacted by data breach security incidents.
Part I: Reasons for Investing in Application Security
The mitigation of the risks of cyber threats targeting the organization's assets is today one of the CISOs top priorities. This is due to the emerging cyber threats that characterise today's threat landscape. These threat agents are financially motivated and often seek to either steal money or valuable data such as citizen's personal data, customer's financial accounts, client data and business intellectual property data. Because of the continuously evolving cyber threats and attacks increasingly targeting applications, their source code and data, CISOs today focus on the protection of these assets from these cyber threats. For these reasons, one of the primary goals of this guide is to help CISOs managing the risk of cyber threats specifically targeting these. This guide for example will focus on threat analysis and risk management besides the traditional vulnerability management that is done for applications. For example, managing application risks deals with the identification of the value assets such as mission critical applications, the analysis of threats against these assets, the assessment of vulnerabilities exposing these assets and the selection of security measures to reduce potential impacts for the exploit of these vulnerabilities for the business.
Part II: Criteria for Managing Application Security Risks
To make informed decisions on how to manage application security risks, CISOs often need to assess the costs of fixing known vulnerabilities and adoption of new countermeasures and to consider the risk mitigation benefits of doing so. Costs vs. benefits trade offs are critical to decide on which application security measures and security controls to invest in to reduce the level of risk. Often CISOs need to explain to executive management what are the risks to applications and articulate the potential business impacts for the organization in case applications are attacked and confidential data is breached. Often a CISO is asked by the business executives to articulate what are the business impacts of potential attacks directed to steal the organization intellectual property and digital assets to understand if the risks are unmitigated so they can decide if it is necessary to invest in new application security measures to mitigate these risks. The aim of this guide is to help CISOs in articulating the needs for application security to the business by analysing the economical impacts derived by the exploits of insecure applications.
One important aspect covered by this guide is to create awareness of the economical impacts caused by the loss and the compromise of confidential data stored and processed by applications. Today's cyber threat landscape is characterised more and more by value driven threat agents rather than the ego driven threat agents of ten years ago. Ego driven threat agents such as script kiddies and hackers sought to exploit computer vulnerabilities for fame. Today's threat agents seek financial gain such as by attacking applications to compromise users' sensitive data and company’s proprietary information for financial gain, fraud as well as for competitive advantage (e.g. through cyber espionage). To mitigate the risks posed by these threat agents, it is necessary to determine the risk exposure and factor the probability and the impact of these threats as well as to identify the type of application vulnerabilities that can be exploited by these threat agents. The exploit of some of these application vulnerabilities might severely and negatively impact the organization and jeopardise the business. The aim of this guide is also to help technical security managers and project managers to prioritise application vulnerabilities for mitigation. Vulnerability management is a critical process for reducing technical risks that the exploit of these vulnerabilities might entail. Unfortunately, just mitigating the risk of application vulnerabilities might not be enough to protect them from attacks of motivated and persistent threat agents seeking to exploit gaps and holes in the deployment and configuration of applications. Even under the assumption that all vulnerabilities identified within an application are fixed, such an application might still be attacked and impacted because of the lack of adequate countermeasures against specific threats. To help CISOs to decide which countermeasures are cost effective for mitigating the risks of specific threats against applications, this guide aims to provide criteria to CISOs for estimating the economical impact that data breach incidents sought by these threats. By estimating the impact for the business of security incidents is possible to compare them with the costs of the security measures to decide which measures to apply.
For risk complacent organizations, the situational awareness of the type of security incidents impacting applications and of the emerging threats causing them, not always translates in the adoption of a new application security measure or of strategic processes to proactively mitigate these risks. For risk adverse organizations, cyber threat awareness of which applications are the primary targets from cyber attacks and incidents might translate in giving CISOs the responsibility for creating a new cyber-threat risk management strategy for mitigating the risk of emerging threats. For organizations that have a conservative approach toward mitigation of the cyber risks a sound risk mitigation strategy consists of proactively managing application security risks. Simply put, proactive risk management in the case of application and software security is one of the goals of security engineering. At a minimum, this includes identifying application vulnerabilities and fixing them before these could be exploited by threat agents and negatively affect the organization's business.
Often vulnerability assessments are just the bare minimum technical risk mitigation process and often these required for compliance with internal information security policies. Unfortunately just identifying vulnerabilities and fixing them is not enough for mitigating the risk of today's emerging cyber-threats. The mitigation of the risk if emerging cyber-threats requires the adoption of new security measures and application security processes that adapt to these cyber-threats. For several organizations the adoption of new application security measures and processes often depends upon different factors besides threat awareness also costs and the organization risk culture also referred by risk managers as the organization "appetite" for risk. This appetite for risk is typically low when one of the organization has been impacted by a security incident and incurred in financial losses as result of it. For some organizations today unfortunately, this is rather the norm then a probability as for many organizations that have already experienced security incidents. Often these security incidents cause significant impact to the business and applications have been targeted resulting in the loss and the compromise of confidential and sensitive data. Because cyber threats are real and impacts noticeable CiSOs are often the ones that are asked by executive management to respond if security incidents involving applications could have been prevented. Unfortunately, for the majority of the CISOs today the question is not "IF" their applications will be impacted by a data breach incident but "WHEN". CISOs therefore need to be prepared to answer these questions more often. One thing that CISOs can do is to make sure application risk are communicated to the business executives such as by providing “emerging cyber-threat awareness” to executive management. CISOs need to be real about cyber-threat risks and present to the business the overall picture of information security risks, not just compliance and vulnerabilities but also security incidents and threat intelligence of threat agents targeting the organization information assets including for applications.
Cyber-threat risk awareness is necessary today to justify a request of spending in application security measures such as processes, tools and technologies to reduce the impact of these cyber-threats to the organization.For CISOs, the understanding of the security investment budgeting constraints, the reasons for investment in application security and the prioritisation of risk mitigation measures within these reasons and constraints is mandatory. For some type of organizations such as financial organizations, the majority of the investments in application security is spent to comply with information security standards and regulatory requirements to pass audits and certifications. For organizations already impacted by security incidents involving applications, the need of investment in application security is for making sure other security incidents in the future won't cause further data losses. In both cases, ability to communicate risks to the business empowers CISOs to articulate the business case for application security and justify additional spending in application security measures. This justification need to consider the economical impact of security incidents comparing with the costs of unlawful non compliance. Today's costs to the business due to the economical impacts of security incidents is much higher than the costs of non-compliance and failing audits. Often the severity of the impact of security incidents might costs CISOs their jobs and the company loosing reputation and revenues.
The focus on mitigating the impact of security incidents targeting applications and software today is no longer an option but a necessity. From risk management perspective, the main questions that CISOs need to answer are "what is the likelihood and impact of application security incidents" and "what are the most cost effective measures to prevent and application security incident". One aspect of risk prevention is focusing on vulnerability testing and vulnerability risk management programs. OWASP is the primary source to provide organizations with the top ten web application risks that need to be mitigated. The testing of OWASP T10 might require organizations to routinely perform security testing of these vulnerabilities in web applications. Once the vulnerabilities are identified and the severity assigned to these, it is important to have a vulnerability management process that allow managers to prioritise the fixes of these vulnerabilities by risk severity but also by the business impacts that might cause in the case these will be exploited by an attacker.But vulnerabilities are just one aspect of risk mitigation for application security risks. Besides managing the risk of application vulnerabilities, it is also important to deploy countermeasures against emerging top cyber-threats targeting applications such as denial of service, hacking and malware.
Another important factor to consider in applying security measures is to follow information security principles and best practices. Today, preventive and detective security controls play an important role in mitigating application security risks and should be considered by CISOs as necessary security measures. There is no silver bullet such and "no one security measure fits all application security needs”. Therefore, proactive and detective security measures need to be implemented at different layers of the application architecture by following security principles such as the principle of “defence in depth” that is to apply layers of security controls that attacks need to break into while at the same time these attacks can be detected and countermeasures can be deployed to resist from them. A good example of application of defence in depth is the mitigation of Distributed Denial of Service (DDoS) attacks agains applications. At the most outer layer that is the edge of the internet it is possible to filter the malicious traffic before attacks the internal layer that is the data centre where the application is hosted and other countermeasures are implemented. As the DDoS attacks take place, defence in depth allows the organization to be alerted and prepare new filtering blocking rules for malicious traffic. But applying the principle of defence in depth, even if it can slow down attackers, is not enough and other defensive security principles need to be followed when deploying countermeasures as well such as to consider control of security of the weakest point, consider the simplicity and openness of the security mechanism so can be managed and vetted securely, apply security as the least privilege for users' access are all essential for the security of the design of security controls of applications and software.
Changes to applications are also are a source of potential risks especially when new or different technologies are integrated within applications. As applications evolve by offering new services to citizens, clients and customers, it is also necessary to plan for mitigation of new vulnerabilities introduced by the adoption and implementation of new technologies such as mobile devices, web 2.0 and new services such as cloud computing. Adopting a risk framework to evaluate the risks introduced by new technologies is essential to determine which countermeasures to adopt to mitigate these new risks. This guide will provide guidance for CISOs on how to mitigate risks of new threats against applications as well as of vulnerabilities that might be introduced by the implementation of new technologies.
Part III: Application Security Program
From the risk management strategic point of view, the mitigation of application security risks is not a one time exercise; rather it is an ongoing activity that requires paying close attention to emerging threats and planning ahead the deployment of new security measures to mitigate these new threats. This includes the planning for the adoption of new application security activities, processes, controls and training. When planning for new application security processes and controls, it is important for CISOs to know on which application security domains to invest. Accessing process maturity is a prerequisite for adoption of application security and software security processes. One criteria that is often adopted by organizations is to consider the organization's capabilities in application security domains and the maturity of the organization in operating in these domains. Examples of these application security domains include application security governance, vulnerability risk management, regulatory compliance and application security engineering such as to design and implement secure applications. Specifically in the case of application security engineering, adopt software security assurance if often necessary when there is not direct control on implementing the security of such software since is produced by a third arty vendor. A factor to consider in this case is to measure the software security assurance using a maturity model. A pre-requisite for measuring software security assurance is the adoption of a Secure Software Development Lifecycle (S-SDLC). At high level, S-SDLC consists on embedding "build security in" security activities, training and tools within the SDLC. Examples of these activities might include software security processes/tools such as architectural risk analysis/ threat modelling, secure code reviews/static source code analysis, application security testing/application vulnerability scanning and secure coding for software developers. A reference to OWASP software assurance maturity model as well as to the several OWASP projects dedicated to software security and S-SDLC are provided in this guide as well.
Part IV: Metrics For Managing Risks & Application Security Investments
Once application security and software security investments are made, it is important for CISOs to measure and report the status of governance, risk and compliance of the application security program to executive management. Metrics for application security are also necessary for management of processes. One necessary tool that helps CISOs are application risk management metrics. The goal of the risk management metrics is to support informed decisions to decide where to focus the risk mitigation effort and to manage application security risks more effectively. These risk management goals are usually very organization specific and depend on the type of organization and the industry sector that the organization does business with, to decide which application security risks should be prioritised for action. For the sake of this guide, some general guidance on application security metrics suitable for measuring governance, risk and compliance of application security processes are also included herein. One aspect that is often neglected when spending on software security is the economics of dealing with insecure software applications. The investment in software security to identify and fix security issues prior to release of software in production actually pays by itself because save the organization money. Patching vulnerabilities after applications are released into production is very expensive; it is much cheaper than to invest in secure architecture reviews to identify design flaws and remediate them prior to coding, as well as to invest in secure code reviews to identify and fix security bugs in software during coding, and to ensure that releases are configured correctly. An example of the metrics that can help CISOs measure the savings in security testing costs incurred by testing software for software vulnerabilities prior to vulnerability penetration testing it is also included in this guide.