We all know and love—or at least begrudgingly rely upon—email. It is a pillar of modern communications, but is unfortunately also highly susceptible to being leveraged as a mechanism for malicious actions, such as spoofing or phishing.

A core concern regarding email is the authenticity of the source, and in recent years, DMARC has arisen as the preeminent email validation system. DMARC builds upon the foundations of two older email authentication systems, Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM), which respectively check for mail server authorisation (“Is the sender authorised?”) and email integrity based on key signatures (“Was the content altered?”). The various components of DMARC can serve to mitigate direct threats as well as potential reputational damage, such as spoofed emails intended to mislead partners, suppliers, or customers.

A properly implemented DMARC system can identify illegitimate emails and define how those emails should be handled. DMARC can be configured to handle emails of suspect provenance with different degrees of severity, depending on the aggressiveness of IT administrators. The DMARC policy options include:

• None, where suspect emails are reported to a designated email address that serves to monitor DMARC notifications.
• Quarantine, where suspect emails are punted to the spam folder and a report of its receipt is delivered to the monitoring email address.
• Reject, where in addition to notifying the monitoring email address, suspect emails are not delivered at all.

By virtue of its efficacy in mitigating malicious messaging via email, we consider DMARC a significant risk mitigator and highly recommend its implementation.  

Unfortunately, while the benefits of DMARC are profound, its implementation is not global.

DMARC's implementations are tracked in public Domain Name System (DNS) records. To determine whether an organisation utilises DMARC only requires the examination of the organisation’s published DMARC record. We are able to discern the scale and types of DMARC implementations by comparing the primary, well-known domains of the FTSE 350 organisation against their corresponding DMARC records that appear alongside DNS.

Note that for the scope of this study, we focus primarily on the apex domains of organisations, and do not explore additional domains owned by particular organisations. We elected this approach because there can be significant variation in domain set ownership by organisation. By focusing on apex domains, we are in effect treating it as a  bellwether indicator of an organisation’s overall email security posture. After all, if an organisation fails to implement DMARC on a primary domain, how confident should we be that the organisation practices healthy email hygiene across for less-prominent domains?

These published DMARC records are intended to be highly accessible. They are the means through which email recipients determine how to validate emails using DMARC, what email address to notify when receiving emails that fail DMARC validation, and what DMARC policy to apply in handling invalid emails.

We can also separate the organisations by industry to get a better sense of DMARC variations across the sectors. The most prominently featured industries in the FTSE 350 include financials, consumer discretionary, industrials, and real estate. Each of these industries reflect large proportions of organisations with apex domains that are not properly configured with valid DMARC policies.

In fact, the vast majority of industries include some set of organisations with domains without valid DMARC implementations, with the exception of the technology sector and the materials sector (though to be fair, neither include a significant count of distinct organisations).

The vast majority of the interactions an average person has with technology is through some form of a web application, but what constitutes a “web app” can be considered quite nebulous, and the security controls for hardening these applications are equally broad. APIs, distributed authentication schemes, single-page applications, and static websites all might fall under the general category of “web application.” There are very few security measures that should be applied to all web applications across the board without further subdividing what specific type of application we are referring to. However, there are a couple that we will examine here.

All web applications should require strong encryption, with a vanishingly small number of exceptions. While this is most critical for applications that are serving up critical or sensitive information, such as personally identifiable information (PII), it is important even if you serve only static informational content. There is a common misconception that the only risk of using an insecure connection is a loss of confidentiality—that the information a user is browsing could be observed by a malicious third party. While this certainly is a risk, it is often overlooked that a lack of encryption makes the connection vulnerable to modification (a loss of integrity). This means that malicious third parties could not only observe potentially confidential information, but that they could alter that information or inject their own content that could potentially compromise your users.

The risk of malicious content injection exists regardless of whether your web application serves sensitive information or just cute pictures of cats. Due to this universal risk to a site’s users and to the overarching brand reputation of the site owner, we will consider the support of strong encryption (in our case, TLS) and the enforcement of its usage via HTTP Strict Transport Security (HSTS). For the purposes of this section, we will look at the primary domain for each company, as it is the domain that is most responsible for a company’s brand reputation.

The outlook for HSTS adoption was not quite as impressive.

As you can see, just over half of the sites examined supported HSTS in some capacity. While this may seem decent at a cursory glance, if the site already fully supports HTTPS (and these sites all do), it should be relatively trivial to implement HSTS to guarantee your users visit the secure version of your site. Many of these sites do provide a redirect from the insecure version of their homepage—however, that will not mitigate a man-in-the-middle (MiTM) attack.

Of the sites that do support HSTS, three of those sites have actually configured it to be explicitly disabled (as of the study time of January 2021), meaning they had supported HSTS at one time, but no longer do. Hopefully, this was a temporary measure to resolve an implementation issue.

Forty-four percent of sites that support HSTS also support the “includeSubDomains” directive, protecting the entire domain and all subdomains. This is a fantastic security feature, but it can be difficult to implement in certain situations.

Thirty percent of sites with HSTS also support the “preload” directive. This directive will cause crawlers to automatically add your site to a global list of known sites that support HSTS. If a supporting browser is directed to a site with HSTS preload enabled, it will guarantee that the first connection is always conducted over HTTPS, meaning it eliminates the one, single place where your site’s users are vulnerable to MiTM attacks—the first connection to your site before an HSTS header has ever been encountered. This configuration option is a simple way to add an extra layer of protection for your users, and if you bother to enable HSTS, you should certainly add this option. While it’s a somewhat newer directive with less browser support, there is no downside to including it (browsers that do not support HSTS will simply ignore it).

If you haven’t thought about your site’s encryption for a while, now might be the time to revisit it.  A company’s brand reputation is on the line when consumer-facing web applications suffer from security failures, and it’s important to consider this fact when making investment decisions in various security programmes. If your company’s website is not supporting HSTS, it might be worthwhile to find out why. Is it a technical, organisational, or budgetary constraint? Finding the cause could be a great springboard for re-evaluating your entire application security programme.

Back in 2018, when we began our first foray into analysing the cyber-exposure of the FTSE 350, we created the term “version dispersion” to refer to the diversity of versions within a service component an individual organisation was exposing to the internet. With the dramatic rise⁸ in enterprise use of tooling such as Kubernetes,⁹ we expected to see a reduction in version dispersion of the three web servers—IIS, Apache, and nginx—that we previously measured.

There are at least over 47 distinct versions of Nginx¹⁰, 13 distinct versions of Apache, and 14—yes, 14—versions of IIS¹¹ running across FTSE 350 members. Let’s see how that stacks up per industry.

A higher density of points toward “1” on the X-axis means that each of the organisations those points represent are running with a low version dispersion. This means they have better control over server/service deployments and configurations, have fewer versions to test patches against, and can make changes faster and with more confidence than others. It also likely means they have a more rigorous “you must be this tall to deploy a server on the internet” rules than organisations that are further to the right on the X-axis. Attackers and cyber-insurance assessors alike notice such things and may be more likely to target organisations that exhibit a more “wild, wild west” stature.

For this chapter, we’ll be talking to two different sets of CISOs: those who see their image reflected in the mirrors in each of the sections, and those who have organisations like this as business partners or suppliers.

If you’re a security leader who is working to build resilience and safety into the DNA of your organisation, issues such as technology sprawl, version management, and critical service maintenance are non-negotiable must-haves. The good news is that these aren’t just “security” issues. Organisations deploy services to meet a business need, and it is far easier to sustain service uptime and stability if there are fewer moving parts to maintain. To achieve buy-in with your peers, collect historical and current data regarding service degradation (and/or outages). Add to that data how long it takes IT, application, and operations teams to support each component of each business process. If you pair that up with information on the volume and severity of identified weaknesses (CVE-based or otherwise), you will find areas that have a solid business case to warrant partnering for improvement. As each area ameliorates, you’ll have far more agency to affect change in other, lagging areas.

For those who shuddered at what this section revealed, make sure these are areas you look for when evaluating third parties on behalf of business process stakeholders in your organisation. It’s fairly straightforward to both ensure you’re asking about these potential areas of weakness and verifying ¹⁷ that the answers you receive are accurate. There’s no guarantee that the internal exposure of organisations reflects what is seen externally. However, it is generally more likely that the internal picture is even worse than what is presented to the outside world. Holding your partners and suppliers to a higher level of safety and resilience will not only lessen the risk to your organisation, but can also have a cascading positive effect as other organisations follow the standards you’re setting.

The findings here indicate that even some of the most resourced companies are exposing services that have an outsized risk. 

Our guidance for addressing the risks above isn't to implement some advanced security controls or software, but to instead return to the basics. You can find all of them in the early parts of the CIS Top 20 ³⁰ controls.

• Implement security policies and supporting configuration standards that enforce the use of secure protocols and configuration settings. Using the example of Telnet, every device currently using Telnet should be able to support SSH—and if it doesn't, it is too old or insecure to be directly connected to the internet.
• Ensure that software and hardware are kept current. In many cases, such as with Microsoft Windows, newer software brings better security features and controls. Older software's lack of these features can force security trade-offs and require the implementation of compensating controls, which add complexity.

In January 2019, Casey Ellis, founder of Bugcrowd, remarked in a blog post that only 9% of the Fortune 500 run vulnerability disclosure programmes. ³⁷ Unfortunately, this is about double to the percentage found in the FTSE 350 today. We were able to discover 15 vulnerability disclosure programmes across the 350 ticker symbols investigated in April 2021, which accounts for just about 4% of the FTSE 350 listings.

With such a low showing, it's difficult to say that any particular industry or valuation quintile has normalised the practice of advertising a VDP—the only industries represented in this set are Consumer Discretionary & Consumer Staples, Telecommunications & Technology, Financials, and Industrials.³⁸

The key takeaway from this view of the FTSE 350 is that, while all major companies have some technical component (and therefore have technical vulnerabilities), nearly 80% of these top companies in the U.S. outside of the technology sector lack a formal vulnerability disclosure programme. While this might be understandable in prior decades, this state of affairs is simply unacceptable in today's hyper-technical business environment.

The lack of VDPs across the upper echelons of the British economy discourages the reasonable and responsible disclosure of newly discovered vulnerabilities in their products, services, and infrastructure—after all, VDPs aren't just for reporting software bugs in software applications, but are also useful for reporting the discovery of sensitive data found about customers or company internals left open on insecure cloud storage. It is, of course, possible to disclose vulnerabilities to companies in industries without a formal VDP, but the lack of VDPs introduces inefficiencies for the companies and legal risk to researchers.

Finally, a functioning VDP signals that a given company has made some investment in their overall information security programme, so it stands to reason that the lack of a VDP is signaling the opposite. Every company on this list has a website privacy policy, so every company should have some formal method for receiving and handling vulnerability reports.

Throughout this report, we've kept our focus on what CISOs in the FTSE 350 can do, today, to reduce their exposure to the most common issues we've discussed here. For the reader's convenience, those recommendations are summarised here.

Email Security: If you're on the Domain-based Message Authentication, Reporting & Conformance (DMARC) path, like 55% of the FTSE 350, that's great! Now is the time to plan out how you'll move from a p=none to a p=quarantine policy, and ultimately a p=reject policy. This is not an easy journey, since you will certainly uncover pockets of shadow IT running their own email infrastructure, but the confidence of being able to authenticate mail from your major brand domains is a pretty great feeling, and a nice item to report to your board of directors.

Web Security: HTTP Strict Transport Security (HSTS) is rapidly becoming table stakes for running a reasonably secure website, and this is the kind of security feature that browser manufacturers like Google, Apple, Microsoft, and Mozilla are likely to enforce in future versions of Chrome, Safari, Edge, and Firefox. It's a relatively easy switch that CISOs can flick (compared to the universe of nice-to-haves in cybersecurity, anyway), so take some time to investigate whether your organisation is using HSTS and if not, why.

Version Dispersion: For the mega-corporations that roam the fields of capitalism, mergers and acquisitions are a fairly common activity throughout the year. That means the FTSE 350 CISO is never truly "done" with ensuring version consistency across the enterprise, even after investing in an excellent asset and vulnerability management toolchain. New networks and network services will join your ranks, and that means undertaking a fairly continuous modernisation and normalisation effort for those new assets. Taking on this continuous effort will pay off in easier, more straightforward planning for the next patch cycle, scheduled or surprise.

High-Risk Services: Telnet, SMB, and RDP have no business being exposed directly to the world at large, and are just waiting for the next self-replicating cyberattack to sweep across the internet. An up-to-date inventory of exposed services, sourced from internal and external scanning, is worth its virtual weight in Bitcoin, and will help you enforce a no-nonsense policy of network service exposure to the internet.

Vulnerability Disclosure Programmes: As a CISO, you might have hired on the best of the best software, QA, and platform engineers. But, without a good way to harness the smarts of the tens of thousands of talented hackers around the world, you may never learn about the most critical vulnerabilities in your products and services. A VDP is a bridge to that enormous community of well-meaning investigators who have goals aligned with your own: a safer and more secure internet. Getting that programme spun up now will give you plenty of time to practice safer software production. As a bonus, most of the pioneering work is already done for you, in the form of ISO 29147 and ISO 30111.