What are Backdoor Trojans?

Backdoor Trojans are malicious software programs that provide unauthorized access to a computer in order to launch a remote attack. Remote attackers can use a hacked machine to send commands or gain complete control.

Backdoor malware and viruses circumvent authentication protocols in order to gain access to systems and avoid detection. Once a Trojan has gained a footing in a system, it adds itself to the starting routine of the computer, preventing harmful programs from being permanently terminated by rebooting the machine.

Backdoor malware is commonly referred to as a Trojan. A Trojan horse is a malicious computer software that masquerades as something it isn't in order to spread malware, steal data, or open a backdoor on your system. Computer Trojans, like the Trojan horse from Greek mythology, usually come with a terrible surprise.

  • Trojans are a highly adaptable tool in the arsenal of cybercriminals. They can disguise themselves as an email attachment or a file download, and they can convey a variety of malware threats.

  • Backdoor Trojans may masquerade as legitimate software in order to deceive users into executing them. They can also be disseminated via spam email attachments or malicious URLs.

  • Using a backdoor, a Trojan allows an attacker to get remote access to a computer and take control of it. This gives the bad actor complete control over the device, allowing them to delete files, reset the machine, steal data, and install malware.

  • As a gateway, backdoor trojans have the potential to either install malware on your system or, at the absolute least, expose your machine to attack.

  • Backdoors are routinely used to build botnets. Without your knowledge, your system becomes a part of a zombie network that is used for attacks.

  • Backdoors may also be used to monitor your Internet behavior and run code and instructions on your device.

How Does a Backdoor Trojan Affect a System?

To effectively install a backdoor virus on your computer, thieves must first identify a weak spot (system vulnerabilities) or a hacked program.

Here is a list of some of the most prevalent system flaws −

  • Software that has not been patched

  • Ports on the network should be open

  • Passwords that are easy to guess

  • Firewalls that are ineffective

  • A piece of malware, such as trojans, can also generate vulnerabilities. Backdoors are created by hackers using trojans that already present on a device.

A backdoor trojan, once triggered, allows hackers to take control of the infected device remotely. They may steal, receive, and delete files, reset the device, and install malware, among other hazardous behaviours.

Hackers will want to make sure they can rapidly re-enter your computer after gaining access through a backdoor infection so they can steal your data, install crypto mining software, hijack your device, or harm your business. And hackers are well aware that re-hacking a device may be tough, especially if the vulnerability is patched.

  • Remote File Inclusion (RFI), an attack vector that targets weaknesses inside programs that dynamically reference external scripts, is the most common backdoor installation method. The reference function is fooled into downloading a backdoor virus from a remote host in an RFI situation.

  • Scanners are commonly used by perpetrators to find websites with unpatched or obsolete components that allow for file injection. After that, a successful scanner exploits the flaw to install the backdoor on the underlying server. It can be accessible at any moment after it has been installed, even if the vulnerability that allows it to be injected has been patched. That is why, they install a backdoor on the target device, so that even if the vulnerability is addressed, the backdoor will still allow them to access the device.

  • To get around security regulations prohibiting the upload of files larger than a particular size, backdoor trojan injection is frequently done in two steps.

    • The first step is to install a dropper, which is a tiny program whose primary purpose is to retrieve a larger file from a remote site.

    • The second phase begins with the backdoor script being downloaded and installed on the server.

Trojans may occasionally duplicate themselves and propagate to new computers without any extra orders from the cybercriminals who built them, similar to how worms do.

  • Take the Emotet Banking Trojan, for example. Emotet began as an information thief in 2014, spreading across devices and collecting critical financial information.

  • Since then, Emotet has grown into a vector for the distribution of various types of malware. According to the State of Malware report, Emotet helped make the Trojan the top threat detection for 2018.

Updated on: 09-Jun-2022

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