A Trojan horse, often referred to as a Trojan, is a type of malicious software that disguises itself as a legitimate program or file to deceive users into downloading and executing it. Once activated, a Trojan can perform various malicious activities on a computer, and this may include actions that impact files. Here are some of the things a Trojan horse can do to files on a computer:
1. **Data Theft:**
- Trojans may be designed to steal sensitive information, such as personal data, login credentials, or financial information stored in files on the infected computer.
2. **File Modification or Deletion:**
- Trojans can alter, delete, or corrupt files on a targeted system. This can lead to data loss, system instability, or disruptions in the normal functioning of applications.
3. **Backdoor Installation:**
- Some Trojans create a backdoor, allowing unauthorized access to the infected system. Attackers can then manipulate or delete files remotely.
4. **File Encryption (Ransomware):**
- Certain Trojans, known as ransomware, encrypt files on the infected computer and demand a ransom for the decryption key. This type of attack can result in the user losing access to critical files unless a payment is made.
5. **Propagation:**
- Trojans may spread by attaching themselves to files and documents, enabling them to be distributed to other computers when shared or transferred.
6. **Keylogging:**
- Trojans with keylogging capabilities can record keystrokes, capturing sensitive information entered by the user, including passwords and confidential data stored in files.
7. **Spying and Surveillance:**
- Some Trojans are designed for espionage, monitoring and exfiltrating information from files, emails, and other communication channels.
8. **Botnet Recruitment:**
- Trojans can be used to recruit infected computers into a botnet, a network of compromised computers controlled by a malicious actor. These botnets can be utilized for various malicious purposes, including launching coordinated attacks.
To protect your computer from Trojans and other malware, it's crucial to maintain up-to-date antivirus software, use firewalls, be cautious of downloading files from untrusted sources, and keep your operating system and software patched with the latest security updates. Regularly backing up your important files can also help mitigate the impact of a potential infection.