According to US-Cert the USB battery charger may carry a trojan horse that allows the attacker to take total control of the users computer.
Energizer DUO is a USB battery charger. An optional Windows application that allows the user to view the battery charging status has been available on the Energizer website. The installer for the Energizer DUO software places the file UsbCharger.dll in the application’s directory and Arucer.dll in the Windows system32 directory. When the Energizer UsbCharger software executes, it utilizes the UsbCharger.dll component for providing USB communication capabilities. UsbCharger.dll executes Arucer.dll via the Windows rundll32.exe mechanism, and it also configures Arucer.dll to execute automatically when Windows starts by creating an entry in the HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run registry key.
Arucer.dll is a backdoor that allows unauthorized remote system access via accepting connections on 7777/tcp. Note that Windows XP SP2 and later systems include a firewall by default.
Occasionally product manufacturers produce products that become infected and distributed to the public. Enegizer stated it removed the infected file from production.
Infoworld sums up a few other products with virus here:
This isn’t the first time that a hardware company has planted malware on unsuspecting customers’ PCs. In 2007, Seagate Technology admitted that an unknown number of its hard drives left an Asian manufacturing plant with Trojan horses, while the year before that Apple warned iPod owners that some of the music players carried a Windows virus .
In early 2008, electronic retailer Best Buy confirmed it had sold digital picture frames with attack code that spread to connected PCs.