A zero-day vulnerability is a software security flaw discovered even before developers are aware of the flaw. And upon discovering the vulnerability that led to the attack, they have “zero days” notice to patch the flaw before the attack takes place.
A zero day is an attack that exploits an unknown flaw, that is, the attack occurs on “day zero” of the vulnerability perception. This means that the developers had zero days to resolve and fix the vulnerability.
Many companies before a launch usually pass the developments to the test teams so that they can detect possible flaws before the launch. Thus, giving the development team time to fix the flaws.
How a Zero Day works
A zero-day attack happens when this flaw or vulnerability is exploited and attackers create and release malware before developers have time to create a patch to fix the vulnerability. Therefore, we call this “day zero”. Let's look at the vulnerability window steps:
- Developers create software, but unbeknownst to them it contains a vulnerability.
- The software now released can fall into the wrong hands that identifies this flaw, and the hacker chooses to exploit the flaw instead of reporting the responsible company.
- The attacker then creates and distributes “malware” exploit code while the vulnerability is still available.
After releasing the fault, the user identifies and reports that there was some type of information theft or problem generated from the software. Or the developer team detects and creates an update patch to fix the problem.
Once a patch is written and used, the exploit is no longer called a zero-day exploit. However, these attacks are rarely immediately discovered. In fact, it often takes not just days, but months, and in some cases even years, before a developer discovers the vulnerability that led to an attack.
How a developer can prevent a Zero Day:
Firstly, multi-layer deployment provides service-independent protection and is the first line of defense if a flaw in any layer is discovered.
The use of Port knocking, which is a method of opening ports externally on a firewall, will perform a series of connection attempts in an already established sequence. In other words, this method works as if it were a password for closed ports, and after this sequence is correct, the firewall rules are temporarily modified to allow the host that “knocked” on the ports to have access.
Likewise, a list of whitelisted IPs somewhat protects against zero-day threats.
Whitelisting will only allow trusted applications to access a system and therefore no new or unknown exploits will be allowed access. While whitelisting is effective against zero-day attacks, a trusted application can also be flawed. In other words, be careful.
Other companies opt for a closed list of users, who carry out beta testing. So if there is any failure, the user would report the occurrences.
And last but not least! Bug Bounty. Today more and more companies are joining bug bounty platforms and so bug hunters or bug hunters in Portuguese, look for failures in order to receive their well-deserved reward.
Therefore, being aware of a series of routines when launching an application not only helps the success of your application in the market. As well as it avoids losses and even lawsuits by users who are harmed.
