DarkHotel (or Darkhotel) is a targeted spear-phishing spyware and malware-spreading campaign that appears to be selectively attacking business hotel visitors through the hotel's in-house WiFi network. It has been characterized by Kaspersky Lab as an advanced persistent threat.
The attacks were specifically targeted at senior company executives, and used forged digital certificates, generated by factoring the underlying weak public keys of real certificates, to convince them that prompted software downloads were valid.
References
DarkHotel Wikipedia(Text) CC BY-SA