The Dreaded Zero-Day Vulnerability

Perhaps the most feared vulnerability in cybersecurity is that of the zero-day. 

A security flaw that only hackers are aware of, once it is exploited there are ‘zero-days’ to fix it, as the attack has already occurred. These are vulnerabilities that software developers do not know of, and have no patch to fix. 

Understanding zero-days 

You may have seen reference to zero-day vulnerabilities, zero-day exploits and zero-day attacks. A better way to understand these terms is zero-day vulnerabilities leave you at risk of zero-day attacks, which occur through zero-day exploits. 

There are different types of vulnerability in software. These can include poorly written code, bugs, unencrypted data or weak passwords. What makes them a zero-day vulnerability is when those interested in resolving the flaw are unaware of it so any fix for it doesn’t exist. At the point the vulnerability is discovered it is no longer considered a zero-day. 

How zero-day attacks work 

1. Within the software there is a security flaw but developers are unaware of it; hence why it is vulnerable to attacks. Threat actors may purchase exploit codes from the dark web, or write their own, which may enable them to spot vulnerabilities.  

2. The vulnerability is discovered and is exploited, often through an injection of malware. The hacker may not be able to inject it remotely themselves so may require social engineering techniques or phishing, so that someone with access can unwittingly perform the injection on their behalf. 

3. Once the exploit is downloaded on the necessary devices, the zero-day attack ensues. The malware injection has the potential to be extremely harmful: stolen data; additional malware installed (including Spyware); corrupted files as well as hackers taking control of other devices. 

4. The attack is detected, and developers have ‘zero days’ to mitigate it. Sometimes it can take a long time before a company realises they have been hacked, maybe months or even years. They are often alerted to it once problems arise related to the malware. Fortunately, sometimes patches can be developed before significant damage is caused.  

The attackers and the victims  

Threat actors may be looking to exploit zero-day vulnerabilities for different reasons. They may just be a hobbyist who is doing it for ‘fun’ and without any real malicious intent. Or they could be a hacktivist, seeking to promote a particular social or political message. Most often, however, the threat actor is likely to be a cybercriminal in search of achieving financial gain. 

The victims may be targeted or non-targeted; and these victims could be individuals, businesses and organisations or government agencies. Through seemingly harmless web browsing activities, a zero-day exploit can infect operating systems, applications, web browsers and hardware with dangerous malware. The attack can occur simply as a result of viewing a website or opening compromised messages and media. 

Avoiding zero-day exploits and vulnerabilities 

Often zero-day vulnerabilities are only detected once they’ve been exploited, and at that point it is too late. A service like Securiwiser can help detect for such vulnerabilities ahead of time. Alternatively, you should: 

• Use antivirus software 
• Always install the latest software updates, to ensure necessary patches are implemented 
• Use a firewall to block suspicious activity 
• Educate yourself and your workforce on the risks of zero-day vulnerabilities and exploits 

Even the most high-profile and sophisticated companies fall victim to zero-day exploits. Four vulnerabilities in Google Chrome were exploited in September alone, taking the total number found in the browser this year up to twelve.  

Prevent zero-day vulnerabilities in the first place to avoid the grim consequences it can have for your business, or make sure you have the necessary tools in place to mitigate exploits if they are found. 

Securiwiser can help to identify vulnerabilities before it’s too late. Get a free trial today.