What Are Backdoors And How they work ??

Rachitpandya
4 min readOct 4, 2020

Many of you might have come across the term “Backdoors” especially if you talk to someone interested in the field of cybersecurity. Ever wondered what they are?.

If the answer is a “Yes” then read this article to understand what they are and how they operate.

The term “Backdoor”

In general, every house has another door in the backside which is not meant for the entry of guests visiting the house. These doors are usually used by the family members or someone who regularly visits the house or for the maintenance/safety purpose.

The “Backdoors” of the digital world is not much different from the real world example, here too it’s not meant to be used by anyone external but usually is present in our system/network for troubleshooting use.

Digital Backdoors

In simple terms, A backdoor is a means to access a computer system or encrypted data that bypasses the system’s customary security mechanisms.

When someone develops a software he/she might leave backdoor access in it so that when some error comes he/she can use these backdoors to resolve the issue and solve the problems faced by the users.

Till now it might sound that it’s all for the good but unfortunately, that's not the case. These backdoors can turn out to be one of the major security threats as they provide someone with direct access to the resources which can possibly cause security failure and harm the privacy of the individual.

Working of a backdoor

There is no standard working or structure of the backdoors, they highly vary in there way and cause of implementation.

While some backdoors are kept in place for administrative purposes there are others which are created by someone trying to cause a security breach. It becomes extremely hard to understand whether a given backdoor is harmful or not.

As stated before there are some backdoors in your system put there by the developers which are not harmful by default but there can be other backdoors created in your system from various other sources.

Few ways in which a backdoor can be inserted in your system are -:

  1. A whole backdoor code might be directly installed in your system through a malware.
  2. A small malware/virus/trojan may be sent to your system which does not actually contain any harmful backdoor code but it runs to download that harmful code in your system from some external links.
  3. someone may exploit an administration backdoor already present in your system ( In this scenario backdoor actually works as a vulnerability but in reality, there is a difference between the two )
  4. A lot of other things like protocols, executable downloads, hidden files etc. can potentially be a source of a backdoor.

Once someone has backdoor access to your system he/she can monitor your work and even upload/download files across systems. In a simple way, he/she access your system as if he/she is the user ( Privilege level of such backdoors varies and that depends on the level of privilege escalation the attacker can reach. )

By now it should be well understood why a backdoor is dangerous.

How to detect backdoors

A backdoor is hard to make but it’s even harder to detect. It will be a nightmare for you to actually track down the code which creates the backdoor especially if you are not familiar with this domain.

So your best bet, in this case, is to use the phrase “ Precaution is better than cure”. By this I mean you can relly on some advance antivirus systems ( not the free basic ones ) to detect those backdoors for you.

In some cases, you can also use network protocol monitoring tools to check the packets and detect if there is some malicious code in there.

The last solution that could save you is to use a properly configured firewall so that it can take care of those backdoors on your behalf.

Final note

Backdoors come in many shapes and sizes; they are created by developers or service providers for remote troubleshooting or other official reasons, or through malware. But, no matter who created it and why a backdoor can be used to gain access for malicious intent.

Backdoors are difficult to spot because hackers disguise them as regular files. The only way to tackle a backdoor attack is by using an antivirus, security scanners, and cleaners to block unauthorized backdoor access and to weep out any accompanying malware.

By now you must have understood that the effectiveness, as well as prevention of a backdoor, also depends on the operating system you are using currently.

Lastly, there might be a lot of tools available against malware, backdoors, trojans etc but according to me the most powerful and essential of them is the tool called AWARENESS.

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