One minute you download an interesting email attachment from overseas, and the next thing you know, you find yourself locked out. In this case, you’re probably experiencing a Trojan Horse attack. The malware’s name is inspired by the classic household tale of The Trojan Horse. Legend has it that the Greeks hollowed out a wooden horse and smuggled soldiers into the city of Troy. In our case, malicious codes are hidden inside a trojan and wait for the opportune moment to destroy your device and network - just like the soldiers creeping out in the story.

Among all existing malware, the trojan horse is one of the most dangerous kinds, especially for businesses. This malware is the major cause of over half of the cybersecurity incidents reported. Given its ability in capturing keyboard strokes, trojans often record secret passwords to get access to confidential business data. Trojans can also amend or remove essential files, leak data externally, or expose them to open sources. In the following glossary, we will learn more about what is a Trojan Horse attack and how does it work.

What is a Trojan Horse Attack in Cybersecurity

Trojan Horse Attack

Named after the Ancient Greek myth, Trojan Horse is malware concealing its true, harmful content and fooling users. Similar to Troy’s wooden horse, malicious code inside a Trojan Horse virus disguises itself as a legitimate application. Once the system is infiltrated, Trojan Horse programs initiate attacks, which pose a variety of threats. 

The hidden nature of the Trojan Horse attack is what makes it so dangerous. This is a type of malicious code designed to wreak havoc on its victim’s computers, all while going unnoticed. It can be challenging for users to identify the infection before attackers begin to hold systems or files hostage. 

How does a Trojan Horse Attack work?

Although Trojan Horse malware cannot replicate itself like other cyber threats, it opens the door for further malware installation. As such, a Trojan Horse virus is often the beginning of a full-scale cyber-attack. It also performs functions like stealing confidential information, modifying or blocking access to data and recording keyboard strokes. 

Trojan Horse attacks take advantage of the user’s lack of cybersecurity knowledge with social engineering techniques. One of the most common forms of trojans is an email attachment. By pretending to be coming from a trusted source, the malware aims to trick recipients into downloading it. 

Note that Trojan Horse attacks are not just problems for computers but also mobile devices. For phones and tablets, trojans loaded up with malware are often disguised as official applications on pirate app stores. That’s why sometimes you’d see a warning from your system on whether you trust the source prior to installation. Cybercriminals can also get access to your SMSs, banking details, and social media log-ins once your phone is compromised.  

Types of Trojans

Along with the evolution of technology, trojans have grown into more and more complex forms. Read on to see some of the most deadly trojans that you should be aware of. 

Backdoor Trojan

One of the most common types of trojan horse programs, a backdoor trojan “opens up” the system virtually. Hackers can then get remote access to the infected device for more user data. They can also expand the attack surface by loading in more malware. 

DDoS Trojan

Intended to take down a network, DDoS trojans are the starting point of a Distributed Denial of Service. By overwhelming the network with additional requests, hackers cut down users’ and devices’ access to the Internet. Hence, downtime is created due to server failure. 

Downloader Trojan

This kind of trojan targets an already-infected device to install more, latest versions of malicious threats. This involves other trojans and adware, among others.

Game-thief Trojan

Targeting the online gaming community, this type of trojan is designed to escape with gamers’ account information or banking details. 

Infostealer Trojan

As its name suggests, this is a Trojan that specializes in accessing valuable information that is often confidential.

Mailfinder Trojan

This type of trojan is made to acquire email addresses or other contact information collected and stored on specific devices.

Remote Access Trojan

Through the establishment of a remote connection, hackers or trojan holders are granted access to the system. They can then proceed to further spy on system activity or hold the device hostage for ransom. This is called the Remote Access Trojan.

How to spot Trojan Horse Attacks

To combat Trojan Horse attacks, explore these best practices suggested by our team of cybersecurity experts. 

Unexplained system activities

Akin to other malware infections, if you recognize any unfamiliar behavior on your device, there’s probably a Trojan Horse attack taking place. Increased CPU activity or overheated systems are a major indicator for Trojan Horse attacks. 

Repeated System Failures

As trojans install new malware or establish an external connection with its owner, they often overwhelm your system. The loss of Internet access also occurs. The reduction of available bandwidth is often a result of trojans setting up multiple communication channels or connections. If you find your device experiencing continuous crashes, freezes or slowing down significantly, better start a thorough virus scan right away. 

Increase in Spams or Pop-up Windows

Because of trojans’ non-replicable nature, chances are they will lure users into downloading more malware online with spam or pop-ups. Pay extra attention if you start to see more unusual sites or information while browsing the net. Constant display of strange window warnings, messages and question boxes are all bad signs indicating a potential trojan infiltration. 

Unknown Programs

Additionally, unfamiliar application(s) is perhaps the most obvious sign of a Trojan Horse attack. If you discover strange software installed or running on your system, look it up to see whether it’s malware. 

Random Connections to Suspicious Websites

This is a certain sign of compromised systems. Some trojan horse programs  are designed to harvest data or intensify the attack with website redirects against the user’s will or intention. 

Lack of Storage Space

Trojans rely on the further installation of other malware to inflict a cyberattack. Therefore, be cautious whenever you receive warnings of not having sufficient storage space on your device. You should consider digging deeper into background activities and history. 

Random Warning Sounds

When your device starts making random warning sounds, in most cases, it’s not as random as you think. Alert sounds are signals for errors, disconnections or when parts of the system are failing. No matter which one it is, it conveys important information on abnormal system activity. Based on the models and manufacturers, the number of warnings is helping you out by hinting at different problems. Instead of ignoring the alerts, start a system scan immediately and look for more product information online. 

Inability to Use Protection Software

Typically, many malwares deactivate a device’s security defenders the moment they get access to the system. So, if you fail to locate the installed firewall and antivirus software on your device, you are most likely the victim of a Trojan Horse attack.

How Can You Prevent A Trojan Horse Attack?

The main characteristic that sets trojans apart from other malware is the necessity of users downloading them. With that in mind, the best way to defend yourself against Trojan Horse attacks is personal awareness. Here are some aspects where you may want to take extra precautions.  

Use a VPN when downloading from a file-sharing site

In basic terms, a VPN keeps you under hackers’ radar through encryption, or puts data into a coded format. VPN protects your personal data by hiding your IP address, location and browsing history. It protects your identity and secures files when you are downloading from a file-sharing website. This is extremely important in the remote work era. When you are accessing critical files related to organizational interests, this is the way to keep them safe. 

When unsure, do not open an email attachment or IM file. 

This is especially important for Trojan Horse attacks since most of them come from emails. If your antivirus or service provider comes with an email protection feature, scan the attachment before viewing or downloading it. 

For organizations with a sufficient budget, consider investing in a respectable email security solution to fully eliminate the risk. 

Do not visit unsecured websites

Visiting unsecured websites with a device that stores your personal credentials is extremely risky. When you are trying to access a page without proper encryption, browsers often double-check with you by displaying a warning. The warning exists for a reason.

Website browsers have been dedicated to protecting users from that by generating similar messages for years. So, whenever you see one of those warnings, never bypass it.

Do not install apps or programs from unofficial websites or app repositories 

Software providers and programmers don’t just set up official pages and app stores for fun. Download only from trustworthy sources with legitimate certificates.

Check an app’s permissions before installing

A majority of trojans masquerade as a trusted app to use its permissions to perform hostile tasks. To be on the safe side, always spend extra time checking the settings of a newly-installed app. Apart from the essentials that the app needs to execute its function, don’t grant extra permissions and keep your details hidden. 

Use reliable anti-virus software and cybersecurity protection

Just like any other malware, Trojan Horse attacks exploit security vulnerabilities. Keeping your network safe with up-to-date firewalls and antivirus is always the best preventive method. As the frontline defenders of your system, they control malware traffic and potentially stop the attack from the very beginning. 

Contact Sangfor today to see how we can secure your network and device from a Trojan Horse attack or any other cybersecurity threats. 

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