Lydra.O is a worm that spreads by copying itself, without infecting other files.
It captures certain information entered or saved by the user, with the corresponding threat to privacy:
It sends the gathered information to a remote user by any available means: email, FTP, etc.
It reduces the security level of the computer:
it notifies the attacker that the computer has been compromised and is ready to be used maliciously; it awaits remote-control orders received through
other channels; it changes system permissions, decreasing the security level.
Lydra.O prevents access from programs to websites of several companies related with security tools (antivirus programs, firewalls, etc.).
It uses stealth techniques to avoid being detected by the user:
- It uses techniques included in its code to hide itself while it is active.
- It modifies system permissions in order to hide itself.
It uses several methods in order to avoid detection by antivirus companies:
- It prevents scanning tools from running, such as Windows Registry Editor, FileMonitor, etc.
- Its code is encrypted and it is only decrypted when it is going to run. Because of this, its code is not legible through a memory dump.
Lydra.O uses the following propagation or distribution methods:
- Exploiting vulnerabilities with the intervention of the user: exploiting vulnerabilities in file formats or applications. To exploit them successfully it needs the intervention of the user: opening files, viewing malicious web pages, reading emails, etc.
- Email: sending emails that include a copy of itself as an attachment. The computer is infected when the attachment is run.