Imagine you own a mansion full of priceless antiques, high-end appliances and expensive jewelry, on a highly trafficked street. While the majority of passersby simply want to get from point A to point B, you realize that a few less scrupulous onlookers might have malicious motivations. So, you put up a security gate and deadbolt your door each day.
But there’s a problem: Your gate isn’t tall enough and there’s a first-floor window with a broken lock. Worst of all? There’s a man who patiently waits every day for you to leave so he can stake out your property. Is it all that surprising when, eventually, you come home to discover you’ve been robbed?
Unfortunately, this is a scenario that federal IT teams increasingly face, tasked with securing stores of sensitive, valuable data, but with too few defenses standing between their networks and the hackers determined to penetrate them. And, just like the robber needs only an unlocked window, hackers need only one vulnerable endpoint to penetrate an entire network.
In February 2017 alone, an estimated 94.1 million new malware variants emerged, nearly tying October 2016’s record high. Likewise, recent years have seen multiple massive breaches of federal networks, each resulting in major risk and embarrassment to the agencies and to the citizens with whose data they’re entrusted. Meanwhile, the number of ill-intentioned passersby—and the sophistication of their methods—continues to rise.
Of course, the higher a target’s value, the more effort hackers will make to infiltrate their networks and deliver the intended payload. Consequently, no matter how intricate the firewall or how current the antivirus software, there’s always someone smart, resourceful and determined enough to clear the gate and find the open window. And there’s always a user who’s just vulnerable enough to leave that window open—and that window is typically attached to individual devices, or endpoints.
Hackers understand that individual endpoints are often the surest route to their larger target: the entire organization. Knowing this, today’s sophisticated hackers often embrace multi-phase attacks that begin by targeting end users until they find an “in.” From there, they can employ any number of tools and strategies to penetrate their target’s IT environment, culminating in the release of a payload—usually malware.
To catch a thief, you have to think like one—and hackers are no different. So, first, let’s look at two of the more popular tactics for hackers looking to penetrate a target’s network.
Usually just the first step in a multi-phase attack, spear phishing is essentially a more involved, focused form of phishing. This attack method generally targets organizational higher-ups: executive-level leaders whose emails other users are most likely to open, read and trust. It also heavily relies on human error and vulnerability.
Because of that human factor, defending against spear phishing is difficult. Hackers spend substantial time gathering intelligence on an organization, including individual users. Such information is readily available online, often through public social media profiles.
Using that information, spear phishers craft emails that appear to come from a known contact and that have an air of credibility, relevance and familiarity. They might even address the target—perhaps an agency leader—by name and include specific information about the victim and his organization. One way or another, the hacker tricks the recipient into divulging his login credentials, which he then uses to send emails to the entire organization, encouraging employees to click on a link.
And, because the email appears to come from a C-level leader, employees confidently click away. Consequently, those users unwittingly become a hacker’s entry point to the agency’s entire network.
What does that mean? Zero-day attacks exploit vulnerabilities as yet unknown to product vendors or the public. Attackers often reserve the use of zero-day exploits for their highest-value targets, such as major corporations or government agencies.
Zero-day attacks can be delivered via email (e.g., a malicious attachment), “drive-by” download (e.g., a compromised website), or steganography (e.g., embedded in the metadata of visual files). While firewalls and antivirus software can sometimes detect and block the delivery of zero-day attacks, those hackers who are sophisticated enough to discover and weaponize zero-days are also usually smart enough to bypass traditional antivirus software and firewalls.
Even after discovery, zero-days pose a significant threat if systems and applications remain unpatched—and firewalls and antivirus are of little assistance. Take, for instance, Heartbleed—a serious vulnerability in OpenSSL cryptographic software that emerged in 2014. Unpatched, this bug leaves network vulnerable to significant data theft. Yet, as of January 2017, 200,000 systems still had not been patched.
Of course, zero-day and spear phishing attacks are simply steps of a larger campaign. After all, hackers don’t spend huge sums of time and energy to penetrate a network just for fun. Whether motivated by money, revenge or ideology, each step ultimately leads to payload—most often in the form of malware.
And this brings us to two of the more popular forms of malware hackers employ to achieve their ultimate goal.
There’s no question that ransomware has become the malware of choice, particularly for financially motivated hackers.
Ransomware saw exponential growth throughout 2016, arguably becoming the highest-profile exploit among cyber attackers and victims alike. Essentially a means of digital extortion, ransomware allows cyber criminals to steal and encrypt data until the victim pays a ransom—usually paid in the cryptocurrency Bitcoin to command-and-control servers anonymously hosted on the Tor network.
Through a zero-day exploit—particularly where appropriate endpoint security measures are lacking—all it takes is one careless or uneducated end user for hackers to successfully launch a ransomware attack. Lacking proper network segmentation, that ransomware can quickly spread network-wide. Meanwhile, without proper incident response and data backup, ransomware can significantly paralyze an organization, requiring high-volume computer reimagining—if not hundreds of thousands of dollars paid out to the attackers.
If ransomware attacks are predominately financially motivated, Trojans are a favorite for more mission-oriented hackers looking to spy, steal data or access your network. That’s not to say that Trojans are never employed for financial gain—they are, as evidenced by a wave of bitcoin mining attacks earlier this year.
A Trojan horse is a type of malware that appears like a piece of legitimate software. Users are tricked into opening and executing it—often through phishing or social engineering campaigns—thus enabling cyber criminals to access your system. This kind of malware comes in multiple forms, including:
Backdoors, which allows attackers to create a backdoor in order to access and control the user’s computer or device and steal data or even install more malware.
• Downloaders, which enable attackers to download additional content—including malware—to the infected computer.
• Infostealers, which—as the name suggests—allow hackers to steal data.
• Remote Access Trojans, which are designed to give attackers full control of the machine.
• Distributed Denial of Service (DDoS) Trojans, which take down a network by flooding it with traffic.
What makes Trojans particularly challenging is how difficult they are to detect. Because Trojans can be executed without disrupting other software, machines can be infected for a good while before users or IT pros realize there’s been a breach. And, of course, the longer the time to detection, the more damage can be done.
The Devil You Don’t Know
Of course, these are just a small sample of potential threats—hackers have innumerable routes to their end goal. Meanwhile, given their extremely targeted nature, many of today’s threats render traditional security measures (e.g., firewalls, antivirus) significantly less effective. Polymorphic code (i.e., malicious software that constantly mutates) further hinders detection. Then, of course, there are the individual users and their endpoint devices, each one a potential window of opportunity for hackers.
How do you fight a hacker you don’t know, wielding malware you can’t see, aimed at any of numerous endpoints, manned by users over whom you have limited control? Fortunately, new technologies are emerging—for instance, threat intelligence, machine learning, and behavioral analytics—designed to fill the gaps left by firewalls and antivirus software. With endpoints continuously and increasingly under attack, agencies need an endpoint solution that not only detects modern threats, but that can respond to and defend against those threats that get through.
Pete Burke, CISSP, is a security and borderless networks consultant at Force 3.
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