Hidden malware masquerades as patch for Google Toolbar or Adobe Flash.
A hidden malware campaign targeting travelling businessmen has been unearthed by the security company Kaspersky Lab.
Darkhotel lurks on hotel networks waiting for guests to connect to the Wi-Fi, before offering a backdoor download masquerading as an update for common software such as Google Toolbar, Adobe Flash or Windows Messenger.
Kurt Baumgartner, principal security researcher at Kaspersky, said: "For the past few years, a strong actor named Darkhotel has performed a number of successful attacks against high-profile individuals, employing methods and techniques that go well beyond typical cybercriminal behaviour.
"This threat actor has operational competence, mathematical and crypto-analytical offensive capabilities, and other resources that are sufficient to abuse trusted commercial networks and target specific victim categories with strategic precision."
After being installed, the spying software downloads a digitally-signed keylogger and the Karba trojan, which collects data from the system and any installed antivirus software while hunting for cached passwords in web browsers and intellectual property.
Once the malware has completed its tasks the tools are deleted from the network, so the virus can hide until the next victim appears.
"The mix of both targeted and indiscriminate attacks is becoming more and more common in the APT (advanced persistent threat) scene, where targeted attacks are used to compromise high profile victims," Baumgartner added.
"[Meanwhile] botnet-style operations are used for mass surveillance or performing other tasks such as DDoSing (distributed-denial-of-service) hostile parties or simply upgrading interesting victims to more sophisticated espionage tools."
Kaspersky suggests that travellers make use of virtual private networking to access public Wi-Fi through an encrypted connection, and regard software updates offered while on the move as suspicious by default.