If you rely on EC2 instances in at least some parts of your cloud infrastructure, it is important to reduce the attack surface by hardening them. You might want to check out my previous blogs on GuardDuty, Config, IAM and CloudTrail for other tips on securing your AWS infrastructure. But today we are going to be focusing on yet another Amazon service – Inspector.
To start with, we need to make sure the Inspector Agent is installed on our EC2 instances. There are a couple of ways of doing this and I suggest simply using the Inspector service Advance Setup option. In addition, you can specify the instances you want to include in your scan as well as its duration and frequency. You can also select the rules packages to scan against.
After the agent is installed, the scan will commence in line with the configuration you specified in the previous step. You will then be able to download the report detailing the findings.
The above setup gives you everything you need to get started but there is certainly room for improvement.
It is not always convenient to go to the Inspector dashboard itself to check for discovered vulnerabilities. Instead, I recommend creating an SNS Topic which will be notified if Inspector finds new weaknesses. You can go a step further and, in the true DevSecOps way, set up a Lambda function that will automatically remediate Inspector findings on your behalf and subscribe it to this topic. AWS kindly open sourced a Lambda job (Python script) that automatically patches EC2 instances when an Inspector assessment generates a CVE finding.
You can see how Lambda is doing its magic installing updates in the CloudWatch Logs:
Or you can connect to your EC2 instance directly and check yum logs:
You will see a number of packages updated automatically when the Lambda function is triggered based on the Inspector CVE findings. The actual list will of course depend on how many updates you are missing and will correspond to the CloudWatch logs.
You can run scans periodically and still choose to receive the notifications but the fact that security vulnerabilities are being discovered and remediated automatically, even as you sleep, should give you at least some peace of mind.
There are several ways to implement threat detection in AWS but by far the easiest (and perhaps cheapest) set up is to use Amazon’s native GuardDuty. It detects root user logins, policy changes, compromised keys, instances, users and more. As an added benefit, Amazon keep adding new rules as they continue evolving the service.
To detect threats in your AWS environment, GuardDuty ingests CloudTrail, VPC FlowLogs and VPC DNS logs. You don’t need to configure these separately for GuardDuty to be able to access them, simplifying the set up. The price of the service depends on the number of events analysed but it comes with a free 30-day trial which allows you to understand the scope, utility and potential costs.
It’s a regional service, so it should be enabled in all regions, even the ones you currently don’t have any resources. You might start using new regions in the future and, perhaps more importantly, the attackers might do it on your behalf. It doesn’t cost extra in the region with no activity, so there is really no excuse to switch it on everywhere.
To streamline the management, I recommend following the AWS guidance on channelling the findings to a single account, where they can be analysed by the security operations team.
It requires establishing master-member relationship between accounts, where the master account will be the one monitored by the security operations team. You will then need to enable GuardDuty in every member account and accept the invite from the master.
You don’t have to rely on the AWS console to access GuardDuty findings, as they can be streamed using CloudWatch Events and Kinesis to centralise the analysis. You can also write custom rules specific to your environment and mute existing ones customising the implementation. These, however, require a bit more practice, so I will cover them in future blogs.
Committing passwords, SSH keys and API keys to your code repositories is quite common. This doesn’t make it less dangerous. Yes, if you are ‘moving fast and breaking things’, it is sometimes easier to take shortcuts to simplify development and testing. But these broken things will eventually have to be fixed, as security of your product and perhaps even company, is at risk. Fixing things later in the development cycle is likely be more complicated and costly.
I’m not trying to scaremonger, there are already plenty of news articles about data breaches wiping out value for companies. My point is merely about the fact that it is much easier to address things early in the development, rather than waiting for a pentest or, worse still, a malicious attacker to discover these vulnerabilities.
Disciplined engineering and teaching your staff secure software development are certainly great ways to tackle this. There has to, however, be a fallback mechanism to detect (and prevent) mistakes. Thankfully, there are a number of open-source tools that can help you with that:
You will have to assess your own environment to pick the right tool that suits your organisation best.
If you read my previous blogs on integrating application testing and detecting vulnerable dependencies, you know I’m a big fan of embedding such tests in your Continuous Integration and Continuous Deployment (CI/CD) pipeline. This provides instant feedback to your development team and minimises the window between discovering and fixing a vulnerability. If done right, the weakness (a secret in the code repository in this case) will not even reach the production environment, as it will be caught before the code is committed. An example is on the screenshot at the top of the page.
For this reason (and a few others), the tool that I particularly like is detect-secrets, developed in Python and kindly open-sourced by Yelp. They describe the reasons for building it and explain the architecture in their blog. It’s lightweight, language agnostic and integrates well in the development workflow. It relies on pre-commit hooks and will not scan the whole repository – only the chunk of code you are committing.
Yelp’s detect-secrets, however, has its limitations. It needs to be installed locally by engineers which might be tricky with different operating systems. If you do want to use it but don’t want to be restricted by local installation, it can also run out of a container, which can be quite handy.
Let’s build on my previous blog on inventorying your AWS assets. I described how to use CloudMapper‘s collect command to gather metadata about your AWS accounts and report on resources used and potential security issues.
This open source tool can do more than that and it’s functionality is being continuously updated. Once the data on the accounts in scope is downloaded, various operations can be performed on it locally without the need to continuously query the accounts.
One of interesting use cases is to visualise your AWS environment in the browser. An example based on the test data of such a visualisation is at the top of this blog. You can apply various filters to reduce complexity which can be especially useful for larger environments.
Another piece of CloudMapper’s functionality is the ability to display trust relationships between accounts using the weboftrust command. Below is an example from Scott’s guidance on the use of this command. It demonstrates the connections between accounts, including external vendors.
I’m not going co cover all the commands here and suggest checking the official GitHub page for the latest list. I also recommend running CloudMapper regularly, especially in environments that constantly evolve.
An approach of that conducts regular audits. saving reports and integrating with Slack for security alerts is described here.
In the previous blog, I wrote about how you as a security specialist can succeed in the world of agile development, where the requirements are less clear, environment more fluid and change is celebrated not resisted.
Adjusting your mindset and embracing the fact that there will be plenty of unknowns is the first step in adopting agile security practices. You can still influence the direction of the product development to make it more resilient, safe and secure by working with the Product Owner and contributing your requirements to the product backlog.
Simply put, product backlog is a list of desired functionality, bug fixes and other requirements needed to deliver a viable product. There are plethora of tools out there to help manage dependencies and prioritisation to make the product owner’s job easier. The image at the top of this post is an example of one of such tools and you can see some example requirements there.
As a security specialist, you can communicate your needs in a form of user stories or help contribute to existing ones, detailing security considerations. For example, ”Customer personal data should be stored securely” or “Secure communication channels should be used when transmitting sensitive information”. Below are a couple more examples from different categories.
When writing security user stories, you should try and elaborate as much as possible on the problem you are trying to solve, what value it will provide if solved and the acceptance criteria. Each story will then have points assigned which signifies how much effort a particular functionality will require. The process of arriving to the final number is quite democratic and usually involves playing planning (sometimes also called Scrum) poker in which every developer will estimate how long each story is going to take with some discussion and eventual consensus. You can do it with an app as on the image below, or the old school way with a deck of cards.
You don’t have to use the above number pattern, and opt-in instead for the Fibonacci sequence or T-shirt sizes.
It’s important that the security team is involved in sprint planning to contribute to the estimates and help the product owner with prioritisation. Other Scrum meetings, like backlog refinement and daily stand-ups are also worthwhile to attend to be able clarify your requirements (including value, risk, due dates and dependencies) and help remove security related impediments.
A culture of collaboration between teams is essential for the DevSecOps approach to be effective. Treating security as not something to workaround but as a value adding product feature is the mindset product and engineering teams should adopt. However, it’s up to security specialists to recognise the wider context in which they operate and accept the fact that security is just one of the requirements the team needs to consider. If the business can’t generate revenue because crucial features that customers demand are missing, it’s little consolation that security vulnerabilities have been addressed. After all, it’s great to have a secure product, but less so when nobody uses it.
Outline security requirements at the beginning of the project, review the design to check if the requirements have been incorporated and perform security testing before go-live. If this sounds familiar, it should. Many companies manage their projects using the waterfall method, where predefined ‘gates’ have to be cleared before the initiative can move forward. The decision can be made at certain checkpoints to not proceed further, accepting the sunk costs if benefits now seem unlikely to be realised.
This approach works really well in structured environments with clear objectives and limited uncertainty and I saw great things being delivered using this method in my career. There are many positives from the security point of view too: the security team gets involved as they would normally have to provide their sign-off at certain stage gates, so it’s in the project manager’s interest to engage them early to avoid delays down the line. Additionally, the security team’s output and methodology are often well defined, so there are no surprises from both sides and it’s easier to scale.
If overall requirements are less clear, however, or you are constantly iterating to learn more about your stakeholder’s needs to progressively elaborate on the requirements, to validate and perhaps even pivot from the initial hypothesis, more agile project management methodologies are more suitable.
Embedding security in the agile development is less established and there is more than one way of doing it.
When discussing security in startups and other companies adopting agile approaches, I see a lot of focus on automating security tests and educating developers on secure software development. Although these initiatives have their merits, it’s not the whole story.
Security professionals need to have the bigger picture in mind and work with product teams to not only prevent vulnerabilities in code, but influence the overall product strategy, striving towards security and privacy by design.
Adding security features and reviewing and refining existing requirements to make the product more secure is a step in the right direction. To do this effectively, developing a relationship with the development and product teams is paramount. The product owner especially should be your best friend, as you often have to persuade them to include your security requirements and user stories in sprints. Remember, as a security specialist, you are only one of the stakeholders they have to manage and there might be a lot of competing requirements. Besides, there is a limited amount of functionality the development can deliver each sprint, so articulating the value and importance of your suggestions becomes an essential skill.
Few people notice security until it’s missing, then the only thing you can notice is the absence of it. We see this time and time again when organisations of various sizes are grappling with data breaches and security incidents. It’s your job to articulate the importance of prioritising security requirements early in the project to mitigate the potential rework and negative impact in the future.
One way of doing this is by refining existing user stories by adding security elements to them, creating dedicated security stories, or just adding security requirements to the product backlog. Although the specifics will depend on you organisation’s way of working, I will discuss some examples in my next blog.