Much of the spam in your e-mail inbox, and as much as 10 percent of malware on Microsoft Windows computers, is generated by the “Storm botnet,” a remotely controlled network of zombie computers running on as many as 50 million computer systems worldwide. The Storm botnet was only identified early last year, and the FBI has had little luck so far in tracking its origins or creators.

But we’ve apparently learned one thing: Prescription drug spammers are bankrolling the Storm botnet’s growth.

According to Tim Wilson at Dark Reading, reporting on a study by IronPort, Cisco’s e-mail security unit:

More than 80 percent of Storm botnet spam advertises online pharmacy brands. This spam is sent by millions of consumers’ PCs, which have been infected by the Storm worm via a multitude of sophisticated social engineering tricks and Web-based exploits. Further investigation revealed that spam templates, “spamvertized” URLs, Website designs, credit card processing, product fulfillment, and customer support were being provided by a Russian criminal organization that operates in conjunction with Storm, IronPort says.

This criminal organization recruits botnet spamming partners to advertise their illegal pharmacy Websites, which receive a 40 percent commission on sales orders. The organization offers fulfillment of the pharmaceutical product orders, credit card processing, and customer support services.

However, IronPort-sponsored pharmacological testing revealed that two thirds of the shipments contained the active ingredient but were not the correct dosage, while the others were placebos.

Scary stuff. As we’ve been preaching for years, NEVER — under ANY circumstances — respond to an unsolicited e-mail from an online pharmacy. Legitimate pharmacies DO NOT SPAM YOU. If you respond to an e-mail solicitation, you are putting your health, and perhaps even your life, at risk.