What Is A Backdoor and How to Protect Against It

Aviva Zacks
Posted: September 2, 2018

“Did I forget to lock the door?” That scary thought usually comes to mind when you’re already halfway across town and it’s quite disconcerting. Leaving a door unlocked makes it easy for anyone to come inside and take whatever they please.

It’s the same with backdoor attacks, but instead of breaking into your house, criminals enter computer systems to steal data, hijack resources, or plant spyware.

What Are Backdoor Attacks?

A backdoor attack is a covert method of bypassing security restrictions to gain unauthorized access to a computer system. In simpler words, a backdoor is a piece of code that allows others to go in and out of a system without being detected.

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

How Backdoors Are Created

Administrative Backdoors

Backdoors are not always malicious. Sometimes software developers deliberately code backdoors into their applications as a legitimate point of access for remote administration, diagnostics, troubleshooting, or system tests.

These intentional backdoors are convenient and can improve performance and user experience. However, they can also be exploited by hackers to gain access. Hackers often look for administrator backdoors and those known only to the software vendors to break into systems.

In other words, backdoors are not always evil, but they do add another layer of vulnerability that hackers can exploit to gain unauthorized access to a system or data.

Security Organizations

In 2013, other backdoors gained notoriety when Edward Snowden leaked NSA documents to the media. The spy agency, in partnership with Britain’s GCHQ, had been pressuring software makers into installing backdoors.

The issue gained traction again in 2016 when the FBI attempted to force Apple to unlock an iPhone through a lawsuit. The legal battle ended when a private firm broke into the phone, but the public debate about security and privacy is likely to continue.

No matter what side you take on the issue, backdoors leave your system vulnerable to an attack and can give third parties access to your private data.

Malicious Backdoors and Remote Access Trojans

Hackers can also install their own backdoors into targeted systems with the help of a remote access Trojan, or RAT.  A RAT is a piece of malware code that includes a backdoor for administrative control on a target device.

Usually, RATs make their way into the system by tricking the user into downloading them through social engineering and disguising them as legitimate files. For instance, a RAT can be disguised as an email attachment sent by a colleague, a social media link on a friend’s profile, or a video game to download. Once a RAT is installed, hackers can use the backdoor anytime they please.

A remote hacker can access your device through a backdoor to:

  • Install other malware on the system
  • Steal data
  • Download additional files
  • Run tasks and processes
  • Remotely control the device
  • Download or upload files
  • Perform DDoS attacks on other computers
  • Change computer settings, including passwords and user credentials
  • Shut down, restart, or even “brick” the device

Why Backdoors Are Dangerous

When it comes to security, unintended flaws and intentional backdoors are essentially the same. What makes any backdoor dangerous is that at some point it is bound to be discovered by a malicious actor who will be eager to exploit it.

How to Protect Against Backdoors

Backdoor attacks are notoriously difficult to detect. In fact, many users are unaware of the backdoors in their systems for weeks, months, or even years before an attack happens.  However, there are strategies that you can follow to reduce the risk of a breach of this kind.

First, you should have an advanced antivirus solution in place that is capable of detecting and preventing malware and malicious attacks. Many backdoors are installed through RATs, Trojans, and other types of malware, so it is essential to install an antivirus tool capable of detecting such threats.

Your antivirus should provide a firewall and network monitoring as a part of the security suite. A firewall grants access only to authorized users. A strong network monitoring tool can help guarantee that any suspicious activity—such as unauthorized upload or download—is flagged and taken care of.

The Bottom Line

Backdoors come in many shapes and sizes, and this access is sometimes planted by developers or service providers for remote troubleshooting or other official reasons. Backdoors can also be a created through malware. But no matter its origin, any backdoor is a vulnerability that can be exploited.

To prevent backdoor attacks, install strong antivirus protection with top-notch malware detection and prevention capabilities, a firewall, and a network monitoring tool.

About the Author

Aviva Zacks
Aviva Zacks

Aviva Zacks is a content manager, writer, editor, and really good baker. When she's not working, she enjoys reading on her porch swing with a cup of decaf.