DNSChanger.HL is a Trojan, which although seemingly inoffensive, can actually carry out attacks and intrusions.
It reduces the security level of the computer:
it changes the security settings of Internet Explorer, decreasing its security level; it opens one or more ports to allow remote access to the computer and takes action that compromises user confidentiality.
DNSChanger.HL 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 deletes the original file from which it was run once it is installed on the computer.
It uses several methods in order to avoid detection by antivirus companies:
- 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.
DNSChanger.HL does not spread automatically using its own means. It needs an attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, email messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.