Backdoor Attack
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What is a Backdoor Attack?

Cybersecurity personnel constantly tackle the threats related to Backdoor Attacks. They take countermeasures to prevent such attacks. The term Backdoor in English literally means an unauthorized entry, in this case, it is an unauthorized entry into your computer system or smartphone.

It is extremely difficult to detect Backdoor Attacks as they skip the general authentication procedures to access a system. Allowing access to resources within an application such as databases and file servers. As a result of this hackers can remotely issue commands and update malware.

It is not easy to detect a backdoor attack once it’s installed and can also take advantage of vulnerable components in a web application.

What happens when a backdoor is installed?

We already discussed how difficult it is to tackle backdoor attacks once installed. It may lead to a number of malicious activities such as. Theft or destruction of your confidential or personal information. DDoS attacks on competitors can be launched using it as a launching pad.

Defacing competitor’s websites by writing on bulletin boards and SNS without permission. Analyze logs to steal ID, password, and credit card information, after breaking into the records. Infecting visitor’s websites also known as watering hole attacks.

How is a Backdoor trojan installed?

Attackers exploit the vulnerabilities within the application which makes it easier to break into the systems via unauthorized access. In the case of RFI, a referencing function is tricked to download a backdoor trojan from a remote host.

It is usually a two-step process involved to bypass the security rules that disallow the file uploads above a certain size. At first, it installs a dropper ie. a small piece of file used to retrieve a bigger file from a remote location. Once this is achieved in the second phase it downloads and installs a backdoor script on the server.
How to remove a Backdoor Shell?

It is not an easy task once backdoors are installed. They can be traditionally detected using software that scans for known vulnerabilities. Since the backdoor shell files are generally masked, they use alias names or multiple layers of encryption. This makes it extremely difficult to trace as many applications built on external frameworks and use third-party plugins loaded with vulnerabilities or built-in backdoors. Scanners depending on heuristic and signature-based rules are unable to detect such frameworks.

Backdoors detected are also not easy to tackle as they cannot be removed from an application. It is a known fact that backdoors tend to have a persistent presence in rewritable memory.

How to Stay Safe from Backdoor Attacks?

  • Regularly Update your OS and software’s
  • Use security software
  • Avoid visiting untrusted sites
  • Do not install untrusted programs/attachments
  • Purchase network products only from trusted manufacturers