As we return to our Endpoint Advanced Protection series, let’s dig into the lifecycle alluded to at the end of our introduction. We laid out a fairly straightforward set of activities required to protect endpoint devices. But we all know straightforward doesn’t mean easy.
At some point you need to decide where endpoint protection starts and ends. Additionally, figuring out how it will integrate with the other defenses in your environment is critical because today’s attacks require more than just a single control – you need an integrated system to protect devices. The other caveat before we jump into the lifecycle is that we are actually trying to address the security problem here, not merely compliance. We aim to actually protect devices from advanced attacks. Yes, that is a very aggressive objective, some say crazy, given how fast our adversaries learn. But we wouldn’t be able to sleep at night if we merely accepted mediocrity the of our defenses, and we figure you are similar… so let’s aspire to this lofty goal.
- Gaining Visibility: You cannot protect what you don’t know about – that hasn’t changed, and isn’t about to. So the first step is to gain visibility into all devices that have access to sensitive data within your environment. It’s not enough to just find them – you also need to assess and understand the risk they pose. We will focus on traditional computing devices, but smartphones and tablets are increasingly used to access corporate networks.
- Reducing Attack Surface: Once you know what’s out there, you want to make it as difficult as possible for attackers to compromise it. That means practicing good hygiene on devices – making sure they are properly configured, patched, and monitored. We understand many organizations aren’t operationally excellent, but protection is much more effective after you get rid of the low-hanging fruit which making it easy for attackers.
- Preventing Threats: Next try to stop successful attacks. Unfortunately, despite continued investment and promises of better results, the results are still less than stellar. And with new attacks like ransomware making compromise even worse, the stakes are getting higher. Technology continues to advance, but we still don’t have a silver bullet that prevents every attack… and we never will. It is now a question of reducing attack surface as much as practical. If you can stop the simple attacks, you can focus on advanced ones.
- Detecting Malicious Activity: You cannot prevent every attack, so you need a way to detect attacks after they penetrate your defenses. There are a number of detection options. Most of them are based on watching for patterns that indicate a compromised device, but there are many other indicators which can provide clues to a device being attacked. The key is to shorten the time between when a device is compromised and when you realize it.
- Investigating and Responding to Attacks: Once you determine a device has been compromised, you need to verify the successful attack, determine your exposure, and take action to contain the damage as quickly as possible. This typically involves a triage effort, quarantining the device, and then moving to a formal investigation – including a structured process for gathering forensic data, establishing an attack timeline to help determine the attack’s root cause, an initial determination of potential data loss, and a search to determine how widely the attack spread within your environment.
- Remediation: Once the attack has been investigated, you can put a plan in place to recover. This might involve cleaning the machine, or re-imaging it and starting over again. This step can leverage ongoing hygiene tools such as patch and configuration management, because there is no point reinventing the wheel; tools to accomplish the necessary activities are already in use for day-to-day operations.
You need to know what you have, how vulnerable it is, and how exposed it is. With this information you can prioritize your exposure and design a set of security controls to protect your assets. Start by understanding what in your environment would interest an adversary. There is something of interest at every organization. It could be as simple as compromising devices to launch attacks on other sites, or as focused as gaining access to your environment to steal your crown jewels. When trying to understand what an advanced attacker is likely to come looking for, there is a fairly short list of asset types – including intellectual property, protected customer data, and business operational data (proposals, logistics, etc.)
Once you understand your potential targets, you can begin to profile adversaries likely to be interested in them. The universe of likely attacker types hasn’t changed much over the past few years. You face attacks from a number of groups across the continuum of sophistication. Starting with unsophisticated attackers (which can include a 400 pound hacker in a basement, who might also be a 10-year-old boy), organized crime, competitors, and/or state-sponsored adversaries. Understanding likely attackers provides insight into probable tactics, so you can design and implement security controls to address those risks. But before you can design a security control set, you need to understand where the devices are, as well as their vulnerabilities.
This process finds the devices accessing critical data and makes sure everything is accounted for. This simple step helps to avoid “oh crap” moments – it’s no fun when you stumble over a bunch of unknown devices with no idea what they are, what they have access to, or whether they are cesspools of malware.
A number of discovery techniques are available, including actively scanning your entire address space for devices and profiling what you find. This works well and is traditionally the main method of initial discovery. You can supplement with passive discovery, which monitors network traffic to identify new devices from network communications. Depending on the sophistication of the passive analysis, devices can be profiled and vulnerabilities can be identified, but the primary goal of passive monitoring is to discover unmanaged devices faster. Passive discovery is also useful for identifying devices hidden behind firewalls and on protected segments, which active discovery cannot reach.
Just in case you needed further complications, these cloud and mobility things everyone keeps jabbering about make discovery a bit more challenging. Embracing software as a service (SaaS), as pretty much everyone has, means you might never get a chance to figure out exactly which devices are accessing critical resources. For devices that don’t need to go through your monitored corporate networks you need other means to discover and protect them. That could involve a trigger on authentication to a SaaS service, or possibly having your endpoint protection capability leverage the cloud, and phone home to relay device telemetry to a central management system. We’ll dig into these new and emerging use cases later, when we discuss detection and forensics.
Once you know what’s out there, you need to figure out how vulnerable it is. That typically requires some kind of vulnerability scan on discovered devices. Key features to expect from your assessment function include:
- Device/Protocol Support: Once you find an endpoint you need to determine its security posture. Compliance demands that we scan all devices with access to private/sensitive/protected data, so any scanner should assess all varieties of devices in your environment which have access to critical data.
- External and Internal Scanning: Don’t assume adversaries are purely external or purely internal – you need to assess devices from both inside and outside your network. Look for a scanner appliance (which might be virtualized) to scan from the inside. You will also want to monitor your IP space from the outside (either with a scanner outside your network, or a cloud service) to identify new Internet-facing devices, find open ports, etc.
- Accuracy: False positives waste your time, so verifiable accuracy of scan results is key. Also pay attention to the ability prioritize results. Some vulnerabilities are more important than others, so being able to identify the ones truly posing risks to your organization is critical.
- Threat Intelligence: Adversaries move fast and come up with new attacks daily. You’ll want to ensure you factor new indicators into your assessment of security posture.
- Scale: You likely have many endpoints. Today’s large enterprises can have hundreds of thousands – if not millions – of devices that require assessment. Also make sure your tool can assess devices that aren’t always on the corporate network, smartphones & tablets, and hopefully cloud resources (such as desktop virtualization services).
The assessment provides insight into how each specific device is vulnerable, but that’s not the same thing as risk. Presumably you have a bunch of network defenses in front of your endpoints, so attackers may not be able to reach a particular vulnerable device. You need to factor that into your vulnerability prioritization.
It may not be as sexy as advanced detection or cool forensics technology, but these assessment tasks are necessary before you can even start thinking about building controls to prevent advanced attacks. Our next post will dig into reducing attack surface, as well as new and updated technologies to help prevent endpoint attacks in the first place.