Trojan

A trojan, short for “trojan horse,” is a type of malware that masquerades as legitimate software to trick a user into installing or running it. Unlike many viruses, a trojan typically relies on deception rather than self-replication, and once executed it can perform hidden, unauthorized actions such as stealing data, installing additional malware, or giving an attacker remote control.

Trojans commonly arrive through fake downloads, email attachments, malicious ads, or compromised websites. The program appears useful or harmless, for example a “security update,” a game, or a free productivity tool, but its real purpose is to open a backdoor, log keystrokes, copy files, or alter system settings. Some trojans are designed to download other payloads later, which makes them harder to detect because the most damaging behavior may not happen immediately.

In cryptocurrency, trojans are often tailored to steal assets or sensitive secrets. A common example is a fake wallet app or browser extension that looks like a real provider but secretly captures seed phrases, private keys, or login credentials as you type them. Another crypto-focused variant is clipboard hijacking malware, which monitors copied text and swaps a destination address with the attacker’s address right before you paste it into a withdrawal form. Remote access trojans can also take over a device to approve transactions, read 2FA codes, or tamper with wallet software.

Because blockchain transactions are generally irreversible, a successful trojan infection can lead to permanent loss of funds and identity exposure. Understanding trojans helps users evaluate downloads, verify wallet software sources, and treat seed phrases and transaction details as high-risk data, which strengthens security across the crypto ecosystem.