Vendor Security Management: how to decide if tech is safe (enough) to use

tl;dr: Miessler is right. We need to focus on our own risk exposure, not vendor security questionnaires

If you want to make a cybersecurity expert shiver, utter the words “supply chain vulnerabilities”. Everything we do today, depends on a complex mixture of systems, companies, technologies and individuals. Any part of that chain of interconnected parts can be the dreaded weakest link. If hackers can find that weak link, the whole house of cards comes crumbling down. Managing cyber supply chain risk is challenging, to say the least. 

Most companies that have implemented a vendor cybersecurity risk process, will make decisions based on a questionnaire sent to the vendor during selection. In addition, audit reports for recognized standards such as ISO 27001, or SOC2, may be shared by the company and used to assess the risk. Is this process effective at stopping cyberattacks through third parties? That is at least up for debate.

Daniel Miessler recently wrote a blog post titled It’s time for vendor security 2.0, where he argues that the current approach is not effective, and that we need to change the way we manage vendor risks. Considering how many cybersecurity questionnaires Equifax, British Airways and Codecov must have filled in before being breached, it is not hard to agree with @danielmiessler about this. What he argues in his blog is: 

  1. Cybersecurity reputation service (rating companies, etc) are mostly operating like the mob, and security questions are mostly security theater. None of this will save you from cyber armageddon.
  2. Stay away from companies that seem extremely immature in terms of security
  3. Assume the vendor is breached
  4. Focus more on risk assessment under the assumption that the vendor is breached than questionable questionnaires. Build threat models and mitigation plans, make those risks visible. 

Will Miessler’s security 2.0 improve things?

Let’s pick at the 4 numbered points above one by one. 

Are rating companies mobsters? 

There are many cybersecurity rating companies out there. They take measure of themselves to be the Moody’s or S&P’s of cybersecurity. The way they operate is they pull in “open source information about cybersecurity posture” of companies. They also say that they enrich this information with other data that only they have access to (that is, they buy data from marketing information brokers and perform data exchange with insurance companies). Then they correlate this information in more or less sound statistical ways (combined with a good dose of something called expert judgment – or guessing, as we can also call it) with known data breaches and create a security score. Then they claim that using companies with a bad score is dangerous, and with a good score is much better. 

This is definitely not an exact science, but it does seem reasonable to assume that companies that show a lot of poor practice such as a lack of patching, botnet infected computers pinging out to sinkholes and so on, have worse security management than similar companies that do not have these indicators. Personally, I think a service like this can help sort the terrible ones from the reasonably OK ones. 

Then, are they acting as mobsters? Are they telling you “we know about all these vulnerabilities, if you don’t pay us we will tell your customers?”. Not exactly. They are telling everyone willing to pay for access to their data these things, but they are not telling you about it, unless pay them. It is not exactly in line with accepted standards of “responsible disclosure”. At the same time, their findings are often quite basic and anyone bothering to look could find the same things (such as support for old ciphers on TLS or web servers leaking use of an old PHP version). Bottom line, I think their business model is acceptable and that the service can provide efficiency gains for a risk assessment process. I agree with Miessler that trusting this to be a linear scale of cyber goodness is naive at best, but I do think companies with a very poor security rating would be more risky to use than those with good ratings. 

mobster planning his next security rating extortion of SaaS cybersecurity vendors
Some security vendors have a business model that resemble extortion rackets of a 1930’s mobster. But even mobsters can be useful at times.

Verdict – usefulness: rating services can provide a welcome substitute or addition for slower ways of assessing security posture. An added benefit is the ability to see how things develop over time. Small changes are likely to be of little significance, but a steady improvement of security rating over time is a good sign. These services can be quite costly, so it is worth thinking about how much money you want to throw at it. 

Verdict – are they mobsters? They are not mobsters but they are also not your best friends. 

Are security questionnaires just security theater? 

According to Miessler, you should slim down your security questionnaires to two questions: 

  1. “when was the last time you were breached (what happened, why, and how did you adjust)”?, 
  2. and “do you have security leadership and a security program?”.

The purpose of these questions is to judge if they have a reasonable approach to security. It is easy for people to lie on detailed but generic security forms, and they provide little value. To discover if a company is a metaphorical “axe murderer” the two questions above are enough, argues Miessler. He may have a point. Take for example a typical security questionnaire favorite: “does your company use firewalls to safeguard computers from online attacks?” Everyone will answer “yes”. Does that change our knowledge about their likelihood of being hacked? Not one bit. 

Of course, lying on a short questionnaire with Miessler’s 2 questions is not more difficult than lying on a long and detailed questionnaire. Most companies would not admit anything on a questionnaire like this, that is not already publicly known. It is like flying to the US a few years ago where they made you fill out an immigration questionnaire with questions like “are you a terrorist?” and “have you been a guard at a Nazi concentration camp during WWII”. It is thus a good question if we can even just scrap the whole questionnaire. If the vendor you are considering is a software firm, at least if it is a “Software as a Service” or another type of cloud service provider, they are likely to have some generic information about security on their web page. Looking up that will usually be just as informative as any answer to the question above. 

Verdict: Security questionnaires are mostly useless – here I agree with Miessler. I think you can even drop the minimalist axe murderer detection variant, as people who lie on long forms probably lie on short forms too. Perhaps a good middle ground is to first check the website of the vendor for a reasonable security program description, and if you don’t see anything, then you can ask the two questions above as a substitute. 

Stay away from extremely bad practice

Staying away from companies with extremely bad practice is a good idea. Sometimes this is hard to do because business needs a certain service, and all potential providers are horrible at security. But if you have a choice between someone with obviously terrible security habits and someone with a less worrying security posture, this is clearly good advice. Good ways to check for red flags include: 

  • Create a user account and check password policies, reset, etc. Many companies allow you to create free trial accounts, which is good for evaluating security practices as well. 
  • Check if the applications are using outdated practices, poor configuration etc. 
  • Run sslscan to check if they are vulnerable to very old crypto vulnerabilities. This is a good indicator that patching isn’t exactly a priority.

Verdict: obviously a good idea.

Assume the vendor is breached and create a risk assessment

This turns to focus on your own assets and risk exposure. Assuming the vendor is breached is obviously a realistic start. Focusing on how that affects the business and what you can do about it, makes the vendor risk assessment about business risk, instead of technical details that feel irrelevant. 

Miessler recommends: 

  • Understand how the external service integrates into the business
  • Figure out what can go wrong
  • Decide what you can do to mitigate that risk

This is actionable and practical. The first part here is very important, and to a large degree determines how much effort it is worth putting into the vendor assessment. If the vendor will be used for a very limited purpose that does not involve critical data or systems, a breach would probably not have any severe consequences. That seems acceptable without doing much about it. 

On the other hand, what if the vendor is a customer relationship management provider (CRM), that will integrate with your company’s e-commerce solution, payment portal, online banking and accounting systems? A breach of that system could obviously have severe consequences for the company in terms of cost, reputation and legal liabilities. In such a case, modeling what could happen, how one can reduce the risk and assessing whether the residual risk is acceptable would be the next steps.

Shared responsibility – not only in the cloud

Cloud providers talk a lot about the shared responsibility model (AWS version). The responsibility for security of software and data in the cloud is shared between the cloud provider and the cloud customer. They have documentation on what they will take care of, as well as what you as a customer need to secure yourself. For the work that is your responsibility, the cloud provider will typically give you lots of advice on good practices. This is a reasonable model for managing security across organizational interfaces – and one we should adopt with other business relationships too. 

The most mature software vendors will already work like this, they have descriptions of their own security practices that you can read. They also have advice on how you should set up integrations to stay secure. The less mature ones will lack both the transparency and the guidance. 

This does not necessarily mean you should stay away from them (unless they are very bad or using them would increase the risk in unacceptable ways). It means you should work with them to find good risk mitigations across organizational interfaces. Some of the work has to be done by them, some by you. Bringing the shared responsibility for security into contracts across your entire value chain will help grow security maturity in the market as a whole, and benefit everyone. 

Questionnaires are mostly useless – but transparency and shared responsibility is not. 

In Miessler’s vendor security 2.0 post there is a question about what vendor security 3.0 will look like. I think that is when we have transparency and shared responsibility established across our entire value chain. Reaching this cybersecurity Nirvana of resilience will be a long journey – but every journey starts with a first step. That first step is to turn the focus on how you integrate with vendors and how you manage the risk of this integration – and that is a step we can take today. 

Running an automated security audit using Burp Professional

Reading about hacking in the news can make it seem like anyone can just point a tool at any website and completely take it over. This is not really the case, as hacking, whether automated or manual, requires vulnerabilities.

A well-known tool for security professionals working with web applications is Burp from Portswigger. This is an excellent tool, and comes in multiple editions from the free community edition, which is a nice proxy that you can use to study HTTP requests and responses (and some other things), to the professional edition aimed at pentesting and enterprise which is more for DevOps automation. In this little test we’ll take the Burp Professional tool and run it using only default settings against a target application I made last year. This app is a simple app for posting things on the internet, and was just a small project I did to learn how to use some of the AWS tools for deployment and monitoring. You find it in all its glory at https://www.woodscreaming.com.

Just entering the URL http://www.woodscreaming.com and launching Burp to attack the application first goes through a crawl and audit of unauthenticated routes it can find (it basically clicks all the links it can find). Burp then registers a user, and starts probing the authenticated routes afterwards, including posting those weird numerical posts.

Woodscreaming.com: note the weird numerical posts. These are telltale signs of automated security testing with random input generation.

What scanners like Burp are usually good at finding, is obvious misconfigurations such as missing security headers, flags on cookies and so on. It did find some of these things in the woodscreaming.com page – but not many.

Waiting for security scanners can seem like it takes forever. Burp estimated some 25.000 days remaining after a while with the minimal http://www.woodscreaming.com page.

After runing for a while, Burp estimated that the remaining scan time was something like 25.000 days. I don’t know why this is the case (not seen this in other applications) but since a user can generate new URL paths simply by posting new content, a linear time estimation may easily diverge. A wild guess at what was going on. Because of this we just stopped the scan after some time as it was unlikely to discover new vulnerabilities after this.

The underlying application is a traditional server-driven MVC application running Django. Burp works well with applications like this and the default setup works better than it typically does for single page applications (SPA’s) that many web applications are today.

So, what did Burp find? Burp assigns a criticality to the vulnerabilities it finds. There were no “High” criticality vulns, but it reported some “Medium” ones.

Missing “Secure” flag on session cookies?

Burp reports 2 cookies that seem to be session cookies and that are missing the Secure flag. This means that these cookies would be set also if the application were to be accessed over an insecure connection (http instead of https), making a man-in-the-middle able to steal the session, or perform a cross-site request forgery attack (CSRF). This is a real find but the actual exposure is limited because the app is only served over https. It should nevertheless be fixed.

A side note on this: cookies are set by the Django framework in their default state, no configuration changes made. Hence, this is likely to be the case also on many other Django sites.

If we go to the “Low” category, there are several issues reported. These are typically harder to exploit, and will also be less likely to cause major breaches in terms of confidentiality, integrity and availability:

  • Client-side HTTP parameter pollution (reflected)
  • CSRF cookie without HTTPOnly flag set
  • Password field with autocomplete enabled
  • Strict transport security not enforced

The first one is perhaps the most interesting one.

HTTP paramter pollution: dangerous or not?

In this case the URL parameter reflected in an anchor tag’s href attribute is not interpreted by the application and thus cannot lead to bad things – but it could have been the case that get parameters had been interpreted in the backend, making it possible to have a person perform an unintended action in a request forgery attack. But in our case we say as the jargon file directs us: “It is not a but, it is a feature”!

So what about the “password field with autocomplete enabled”? This must be one of the most common alerts from auditing software today. This can lead to unintended disclosure of passwords and should be avoided. You’ll find the same on many well-known web pages – but that does not mean we shouldn’t try to avoid it. We’ll put it on the “fix list”.

Are automated tests useful?

Automated tests are useful but they are not the same as a full penetration test. They are good for:

  1. Basic configuration checks. This can typically be done entirely passively, no attack payloads needed.
  2. Identifying vulnerabilities. You will not find all, and you will get some false positives but this is useful.
  3. Learning about vulnerabilities: Burp has a very good documentation and good explanations for the vulnerabilities it finds.

If you add a few manual checks to the automated setup, perhaps in particular give it a site-map before starting a scan and testing inputs with fuzzing (which can also be done using Burp) you can get a relatively thorough security test done with a single tool.

Defending against OSINT in reconnaissance?

Hackers, whether they are cyber criminals trying to trick you into clicking a ransomware download link, or whether they are nation state intelligence operatives planning to gain access to your infrastructure, can improve their odds massively through proper target reconnaissance prior to any form of offensive engagement. Learn how you can review your footprint and make your organization harder to hack.

https://cybehave.no

Cybehave has an interesting post on OSINT and footprinting, and what approach companies can take to reduce the risk from this type of attack surface mapping: https://cybehave.no/2019/03/05/digital-footprint-how-can-you-defend-against-osint/ (disclaimer: written by me and I own 25% of this company).

tl;dr – straight to the to-do list

  • Don’t publish information with no business benefit and that will make you more vulnerable
  • Patch your vulnerabilities – both on the people and tech levels
  • Build a friendly environment for your people. Don’t let them struggle with issues alone.
  • Prepare for the worst (you can still hope for he best)