malware
Malware is software designed to damage, steal data from, or gain unauthorised access to a device. For bitcoin users, specific malware types such as clipboard hijackers, keyloggers, and fake wallet apps pose a targeted risk to funds and seed phrases.
Malware targeting bitcoin users tends to focus on a small number of high-value attack surfaces. Clipboard hijackers are among the most common: they monitor the clipboard for copied bitcoin addresses and silently replace them with an address controlled by the attacker. A user who copies a receiving address and pastes it without checking may send funds to the wrong destination with no way to recover them. Keyloggers record keystrokes and can capture seed phrases, passwords, or private keys as they are typed. Fake wallet applications that mimic well-known wallets are distributed through unofficial channels and can drain funds or harvest seed phrases immediately after setup. In all these cases, the attack works because bitcoin transactions are irreversible once confirmed.
The practical steps for reducing exposure are straightforward. Downloading wallet software only from official sources, verifying checksums where available, and double-checking the full address before confirming any transaction limits the effectiveness of most clipboard and distribution attacks. Storing seed phrases offline and never entering them into any software unless explicitly restoring a wallet removes the main vector for seed phrase theft. Keeping operating systems and applications updated reduces the attack surface that malware can exploit. For larger holdings, cold wallets that sign transactions on a physically separate device provide a strong layer of protection because malware on the host computer cannot access the private keys.