The malware, WM97/Kukudro-A, has been spammed out with various subject lines, including "worth to see," "prices," "hi" and "hello," according to Sophos.
Graham Cluley, senior technology consultant at Sophos, said the email plays on people looking for the best hardware prices.
"People may be curious as to why they have been sent the email and open the attached file, but doing so would be a big mistake," he said. "The trojan horse will download further code from the internet which could allow hackers to gain access to the computer in order to spy, steal and cause havoc."
The trojan accounted for 35 percent of all malware reported at the company’s monitoring stations from Monday to Tuesday, Sophos said in a statement.
The document, contained in a malicious .zip file attached to the email, contains a Word document entitled my_notebook.doc and has information about Apple, Hewlett-Packard, and Sony products.
Once downloaded, the malware attempts to install another trojan, W32/Kuku-A onto the PC’s hard drive.