Posted on May 13, 2020 at 9:13 AM
As cybercriminals keep improving on their distributed denial of service (DDoS) attacks with more sophisticated tools, organizations need to device more stringent means to keep their system safe. Otherwise, if any network is overrun by Zero-Day or DDoS attack, it could lead to several negative repercussions for the business.
A DDoS attack is simply a malicious attempt to overload or disrupt a network to make it unavailable to its intended user. It is launched to temporarily suspend or interrupt the services of its hosting server. The affected organization can lose its credibility and customers, which eventually leads to financial loss.
There should be a potent security measure in place that will discover the Zero-Day on time and keep necessary measures to prevent any escalation. So, if you’re looking for a reason to foster your network against DDoS attacks, there are many reasons.
Our aim here is to identify and explain the proven methods used in preventing DDoS attack because it’s always good to prevent than to mitigate. But first, let’s get the basics out of the way.
What’s the meaning of Zero-day vulnerability?
A zero-day vulnerability is a software security flaw that is not known to the software vendor and exposes the software to attack. The type of attack is very difficult to mitigate or stop because the vendor doesn’t have any idea about the vulnerability and there is no patch yet.
So, by “zero-day’, it means the developer has “zero days” to fix the vulnerability that has been compromised by the hackers. After the vulnerability becomes known, the software vendor would need to develop a patch to the vulnerability to protect its users.
However, the software vendor may not be able to develop and release the patch on time before hackers infiltrate the system through the patch. When this happens, it’s referred as a zero-day attack.
Types of Zero-Day and DDoS attack
Before knowing the solution to a particular problem, it’s important to know exactly what you are dealing with and which forms it takes. Let’s look at the different types of Zero-Day and DDoS attacks to understand how best to deal with them.
On a broader term, there are three main forms of DoS and DDoS attacks. These include application-layer attacks, Protocol attacks, and Volume-based attacks.
Application Layer Attacks
Attacks of this nature are comprised of innocent and legitimate requests. Once the request is granted, the actors crash the server and render the network unavailable. Examples of these types of attacks include attacks that target Apache, GET/POST floods, and OpenBSD or Windows vulnerabilities.
Protocol attacks consume server resources, unlike other forms of attacks. They also consume immediate communication equipment like load balances and firewalls. Examples include Snurf DDoS, Ping of Death, fragmented packet attacks, SYN floods, and others.
Volume Based Attacks
The main purpose of this attack is to overwhelm the bandwidth capacity of the attacked network, thereby causing the site to reject requests from genuine traffic. These types of attacks include ICMP floods, UDP floods, and other spoofed-packet floods.
How to stop a Zero-Day attack and other DDoS attacks
Zero-Day attacks are most commonly perpetuated even before a solution to the vulnerability is found. That’s why they are very dangerous as hackers can accomplish all their goals before users get patches to vulnerability.
However, there are methods of discovering software vulnerability and fix them before the attackers discover them. These include vulnerability scanning, patch management, as well as input validation. These are effective methods of detecting and blocking impending Zero-Day attacks.
Vulnerability scanning is a popular method of detecting vulnerability before hackers discover them by themselves. Security firms can help you stimulate software code attacks and carry out code reviews. The aim is to find out if there is any vulnerability that sprang up after the software was updated.
This method is an effective way of detecting some vulnerability within the network, but it’s not full-proof. Some vulnerability could still be left in the network even after using the vulnerability scanner.
Even after the scanner has fished out some vulnerability, hackers could still try their luck to infect the system through the weakness. After such vulnerabilities are discovered, it’s important to sanitize the code and perform a code review to keep hackers from exploiting any weakness.
Patch management is the most common action steps taken by companies when they discover system susceptibility. When the vulnerability is scanned and discovered, the next thing is to get software patches in the vulnerability.
However, this method is most commonly utilized to minimize the extent of damage to the systems after an attack, rather than stop an attack. In many cases, security patches do not come immediately after an attack. Sometimes the attacker may have compromised some data before the patch is developed. But with the patch, the organization can block any further exposure the network may have.
This approach could work fine for other forms of DDoS attacks, but it’s inappropriate for Zero-Days because it may take a longer time to get a patch for a Zero-Day attack. The longer it takes the vendor to find a patch the longer the compromised network remains exposed. That’s why Zero-Days are one of the most dangerous forms of cyberattacks in the world.
Sanitation and input validation
When it comes to blocking zero-day attacks, one of the most effective methods is known as input validation. It’s a proactive approach that keeps the hacker off-limits.
The organization can install a web application firewall (WAF) on its network. The main purpose of the firewall is to scrutinize all incoming traffic that may explore security vulnerabilities. It also filters malicious inputs that are sent to explore weaknesses within the network. Once the firewall discovers any fishy activity from any traffic line, it blocks the traffic immediately. This type of security check could sometimes send genuine traffic away, but it has been a proven method of keeping malicious traffic off-limit.
As a result, the zero-day attacker will not be able to discover the vulnerabilities even if they exist.
Input validation is more effective than both the Vulnerability Scanning and Patch Management methods of preventing a zero-day attack. When organizations are patching systems and sanitizing codes, input validation will provide protection and cover for the organization until the vulnerability scanning is complete.
So, while vulnerability scanning and patch management are both important ways of securing your network, they are not the best way to block a zero-day attack. But with the shielding work of WAF software, malicious traffic will not be allowed access into the system until the vulnerability is patched.
There are different types of WAF firewall software organizations can get to enhance their security against malicious zero-day traffic.
Strategies to block DDoS attacks
Although it’s important to deploy an automated system to respond to attacks, it’s also vital to use strategies that can ensure regular availability of services to genuine users.
These strategies include reputation, pattern recognition, and tracking deviation.
This is a source-based blocking strategy that uses threat intelligence provided by DDoS botnet researchers. It also sources information and examines data from millions of vulnerable servers used in reflected amplification attacks. It keeps records of all IP addresses security researchers have discovered were used by threat actors to carry out zero-day and DDoS attacks.
Once the system collects the intelligence data, it uses it to block any IP address in its database that has been previously used for DDoS attacks.
This strategy is used to observe traffic regularly, to discover which traffic is normal and which one should be considered a threat.
Basically, a defense system can analyze query rate or data rate from different characteristics to find out which traffic is genuine and which one poses a threat to the network. The defense system can discover spoofed traffic or bots when they are not able to answer challenge questions.
This type of strategy makes use of machine learning to discover odd patterns of behavior commonly shown by DDoS botnets and patterns of real-time attacks.
Whenever a DDoS or zero-day attack occurs, the system studies the patterns used or deployed by the botnet to infiltrate the systems. It stores this information and uses it to judge against other potential attacks.
If the machine learning algorithm discovers a unique pattern between the present traffic and a previous botnet attack, it blocks the traffic completely. This is one of the most effective methods of preventing zero-day and DDoS attacks because most of the botnets used in DDoS attacks follow similar patterns.
One thing about these DDoS blocking strategies is the fact that they are sophisticated measures and require more computing abilities than random destination protection. They are very effective for organizations that want to prevent or block zero-day and DDoS attacks but allow traffic for legitimate users.
With the high increase of DDoS attacks on organizations, protecting networks against DDoS attacks has never been more important than now. When organizations take the right proactive approach and spot potential attacks on time, they will continue to offer uninterrupted services to their users.