What is the Trojan Horse Virus?

What is the Trojan Horse Virus

Trojan horse malware is a form of software which disguises itself as harmless files in order to gain entry and take control of your device, steal information and provide unauthorised remote access for cybercriminals.

Malvertising or third-party app download portals should always be avoided in favor of official sources like Apple App Store or Google Play for downloading apps and files.

What Is a Trojan Horse Virus?

Trojan horse malware is a type of deceptively harmless file that contains hidden malicious software that will download additional harmful programs onto your device and steal sensitive information from it. Furthermore, these files provide remote hackers access to access it directly and gain entry.

These malicious attacks aren’t as sophisticated as other types of cyberattacks; instead, they rely on social engineering techniques, user interaction, and downloading legitimate-appearing software or apps to spread themselves across devices. Once infected one device becomes infected with another.

Just like Odysseus used a deceptive wooden horse to allow invaders into Troy, Trojan malware allows hackers to gain entry to your device undetected. A good antivirus tool is essential in recognizing cyberattacks and protecting your computer; commonly seen signs include uncharacteristically poor system performance or unexpected programs appearing without your approval.

History of the Trojan Horse

Trojan horse refers to any computer malware which deceives users. While not technically viruses, because they do not self-replicate, trojan horses can still cause serious damage when installed on devices – for instance stealing sensitive data, damaging files and giving attackers remote access into victim systems.

Trojan horses first emerged in the late 1980s with PC-Write, an application designed to delete files on infected computers. More sophisticated trojans such as Back Orifice appeared during this decade allowing attackers to gain control over a victim’s computer without their knowledge or permission.

Amazon employs this tactic successfully in its book business by starting with cheap books and then gradually upping customers’ spending with more costly items. Operation Mincemeat was one of the most successful Trojan horse deceptions. It was intended to divert Axis forces away from attacking Scicily so Allies could enter unopposed.

How Does Trojans Work?

Trojans are difficult to detect because they hide within software and files, making them difficult to spot. Trojans may also spread via emails containing malware attachments or through automated downloads from infected websites; these attacks often exploit vulnerabilities in operating systems, apps and networks. Cybercriminals employ Trojan malware for theft of data, espionage and Distributed Denial of Service (DDoS) attacks while backdoor Trojans enable hackers to remotely gain access to computers, upload, download, execute files at will and change security settings in order to gain entry to other devices on networks.

Trojans can damage or overwrite files on a system, leading to file loss and poor device performance. Other forms of harm they pose to computers or mobile devices include stealing personal information and installing spyware or ransomware programs on them – such as game-thief Trojan which steals online gaming account details, or SMS Trojan which infects mobile phones to send text messages with premium rate numbers that drives up phone costs.

How To Recognize a Trojan Virus?

Trojans are malware designed to take control of systems or gain data that can be used for cyberattacks. Trojans often gain entry through seemingly legitimate files like emails or attachments that appear legitimate before waiting until an opportunity presents itself to launch attacks against individuals or networks. An attacker might attempt to capture keystrokes as you log onto websites, collect forms with login details from you to hijack accounts, or download more malware onto devices – such as ZeuS or Emotet variants of this category of trojan.

People often mistakenly refer to viruses and Trojans as one-in-the-same types of malware, but there are distinct differences between the two forms of infection. One major distinction lies in that viruses can replicate themselves while Trojans need an attacker to install them on a victim’s computer.

Recognizing Trojan threats is essential, given their serious damage potential. Keep an eye out for abnormal computer behavior, unexpected software settings changes and unexpected files or programs appearing without your knowledge on your device.

Types of Trojan

Trojan malware comes in various forms, all with one goal in mind: deceiving users and creating havoc in their systems. Trojans are a form of malware which can harm files, redirect Internet traffic, spy on user activity or steal sensitive data – hence their moniker from Greek mythology’s story of Troy being presented with what looked like an innocent wooden horse, only for it to contain enemy soldiers hidden inside! These threats bear their name after ancient mythology’s myth of The Trojan Horse which deceived Troy into believing it would bring peace.

Individuals can help mitigate their risks of Trojan infections by using antivirus software, avoiding suspicious downloads and updating operating systems regularly. Furthermore, cybersecurity teams should conduct periodic scans of networks and devices to detect any vulnerabilities; notable Trojan malware includes Zeus, Dyre/Dyreza and Tiny Banker which have all been known to steal financial information; other types have been used in ransomware attacks or mining cryptocurrency from compromised computers.

1. Backdoor Trojans

Backdoor Trojans provide attackers with remote access to devices, giving them access to steal data or install malware without being detected by users. Many times they remain undetected for months while telling signs may include computer settings changing unexpectedly or slowing down; many devices also include default accounts and undocumented remote access systems that attackers can exploit.

Like its namesake, these threats conceal malicious code within programs that appear beneficial or harmless. They can “ride along” on free software downloaded from questionable sources like video codec packs or be disguised in email attachments to gain entry.

Once installed on your device, Trojans can perform tasks like logging keyboard actions, taking screenshots, accessing applications and tracking login data, as well as replacing your mobile banking app with one designed to steal credentials. Droppers, also known as Trojans, download and execute other forms of malware like Emotet banking Trojan – making Webroot’s top threat detection for 2018. They sometimes exhibit worm-like qualities by replicating themselves and spreading themselves without further instructions from cybercriminals; such as when replicating themselves to spread to new devices without further commands from cybercriminals as well.

2. Exploit

Trojans are a type of malware that comes in various forms. They’re typically distributed as email attachments, removable storage devices or P2P programs and, once downloaded, create backdoors on devices to steal information or upload more harmful software.

Trojans may serve multiple other purposes as well. A DDoS attack Trojan might attempt to take down an entire network by flooding it with traffic from infected computers; game-thief Trojans can access accounts held by online gamers; while SMS Trojans intercept text messages sent between computers to premium-rate numbers that increase phone costs for infected users.

Trojans pose a significant threat to all end devices in today’s mobile-centric society, from phones and computers to servers and network infrastructures. Fake antivirus Trojans pose particular risk; such malicious code can impersonate legitimate antivirus programs while demanding payment for “detect and remove threats that don’t exist”.

3. Rootkit

Trojans may seem less obvious than viruses, yet attackers still employ them to gain entry to networks and devices. Trojans typically gain entry by exploiting vulnerabilities in security software or operating systems before hiding themselves within legitimate programs or files to remain undetected.

Untruths can bury themselves within common applications like Microsoft Office and even code designed to cheat at video games, making it hard for users to detect any suspicious activity. They may also install files that alter how programs function without the knowledge of users allowing them to steal data and execute commands remotely.

Trojans are one of the most prevalent cyber threats affecting both PCs and Macs. Trojans may come via email scams, torrent downloads or USB drives infected with malware; or simply through being infected through universal serial bus (USB) drives themselves. When installed onto victim machines they can hijack web browsers, take down websites with distributed denial-of-service attacks (DDoS), steal sensitive information from victims’ computers and capture sensitive data – such as gaming account details from online gaming accounts; send text messages with premium rates charges accruing on phone bills; or the banker Trojan which specifically targets credit card and banking accounts – or all three!

4. Banking Trojans

Financial institutions have faced threats of malware attacks against banking transactions for more than a decade now, constantly adapting to new system designs and stronger bank security features.

Banking Trojans can spread via emails containing malicious attachments or legal website advertising that directs visitors to risky sites. Furthermore, they may lurk within mobile applications waiting for someone to use bank services.

One such banking Trojan was disguised as a program combining client apps from several banks, then distributed through fake web pages designed to look exactly like actual bank websites, inducing victims to download a Symbian app which steals banking login credentials.

Some of the most widely known banking Trojan families include Zeus, which offers cybercriminals an easy and accessible toolkit to build their own variants; Panda employing various techniques such as form grabbing and keylogging; KINS using web injection for online banking credentials theft; Anatsa has become more prevalent recently by hijacking victim devices using various techniques to gather sensitive personal data.

5. DDoS Trojans

Trojans are hidden on your device until activated by an attacker and can create backdoors, steal data, redirect Internet traffic and more.

DDoS attacks use Trojans known as botnets to perform distributed denial-of-service (DDoS) attacks against web servers or networks with too much data, effectively shutting them down. DDoS Trojans may also utilize mobile phones and tablets infected with these trojans as part of an attempt to generate revenue by sending SMS text messages with premium rate numbers attached as premium rates.

Banking Trojans seek out and manipulate personal information used for online banking or credit or debit card transactions, or logging console activity or monitoring gaming activity to steal account credentials. Furthermore, some Trojans download additional malware such as droppers, loaders or rootkits – making your experience with banking Trojans an unpleasant one.

6. Fake antivirus Trojans

Trojan malware can infiltrate applications and files and gain control of a device once downloaded by hackers, and may then spy, steal data, release more malware onto it or simply cause physical harm to it.

Backdoor Trojans provide hackers with indirect access to computers, giving them full control to erase files or transfer information without detection. Banker Trojans, on the other hand, target financial records such as account data for credit/debit cards/e-payment systems etc. DDoS Trojans can be used to perform Distributed Denial-of-Service attacks that flood websites with requests that overwhelm and overwhelm their infrastructures.

Signs of Trojan malware infection include an unusually slow computer, unfamiliar programs running in Task Manager and an increased CPU use that seems out of character. By remaining vigilant and staying up-to-date with software patches, you can avoid potential dangers associated with Trojan infections.

7. Trojan-GameThief

Trojan malware steals user account information for online gaming and transmits it back to the criminal behind its attack via email, FTP or the web. Furthermore, some versions may demand a ransom payment in return for undoing their damage.

Trojan-GameThief contains a version of NetBus, an open source program used to gain full remote control over infected computers and install more malware such as trojans and viruses.

Trojan-FakeAV programs impersonate antivirus software and fraudulently claim to detect and eliminate threats that do not exist, in order to extort money from victims by pretending that these nonexistent threats exist and extorting money in return for supposed removal. They’re designed so it becomes harder for antivirus systems to locate their components; Trojan-IM programs target instant messaging services in order to steal logins and passwords (Skype, MSN Messenger, AOL Instant Messenger, ICQ Yahoo Pager etc) before conducting DDoS attacks (distributed denial of service attacks); flooding their target address with requests that exceed its ability to handle.

8. Trojan-Ransom

Trojan malware cannot manifest or spread itself; rather, hackers utilize social engineering tactics to coax end users into clicking or opening infected files.

Some examples of such tactics include providing illegally free programs (cracked software or activation keys for popular video codecs) on dubious websites, while another popular strategy involves coaxing users to click on suspicious emails that contain infected attachments.

Once launched, a Trojan acts as a backdoor and connects to cyber criminals for remote access of an infected device. Attackers using such Trojans have access to files on an infected system as well as data theft from it as well as performing other harmful tasks such as changing ownership on files for future misuse.

GameThief Trojan, for instance, targets online gamers and collects account information about their gaming channels. Other Trojans like Infostealer are known to target financial details like usernames, passwords and credit or debit card payment information from them.

9. Exploit

Trojans can gain entry to computers or devices through visiting dubious websites, downloading free tools or programs or receiving phishing emails. An always-on virus scanner, staying mindful when browsing online and only buying programs from secure sources are all effective tools against Trojans.

Once a device becomes infected with Trojan malware, hackers can exploit its code to execute numerous types of attacks. Some examples include backdoor Trojans that provide remote access for hackers and install other forms of malware; spying Trojans such as Magic Lantern that secretly record user activities and send information back to hacker servers; spying Trojans like Magic Lantern that monitor a user’s activities before transmitting it; banking Trojans like Tinba that steal financial account data from online banks; SMS Trojans which intercept text messages to premium rate numbers so as to drive up phone costs; rootkits which hide objects on an infected device in order to extend malicious software’s presence; keeping all your devices up-to-date with patches, security updates and antivirus software will also aid.

10. SMS Trojans

As with the ancient tale of the Trojan horse, this malware uses SMS functionality on mobile phones to cover its tracks from users and remain undetected until their activities become apparent: typically when phone bills increase unexpectedly or they unexpectedly subscribe to premium numbers without their knowledge.

This Trojan can steal login credentials from instant messaging (IM) services as well as intercept two-factor authentication (2FA) codes to bypass security systems and gain entry to accounts belonging to victims.

This Trojan appears as a media player app and sends text messages to premium-rate numbers that generate income for cybercriminals. Currently affecting Android smartphone users in Russia, however, official app stores may help prevent further infection with such malware by screening out applications which have not been pre-vetted for quality and safety before being made available for purchase.


Greek mythology tells of a Trojan horse as an effective strategy for sneaking past an enemy’s defenses, much like today’s Trojan virus is an efficient means of breaking into networks. By disguising themselves as legitimate code or software, hackers gain entry and can harm files, redirect web traffic or steal data – as well as set up backdoor access points that other threat actors can exploit later. Trojan virus infections may be hidden within downloads for games, tools apps or software patches and may even remain undetected until something goes wrong in an attack.

Sam is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.