Printers vulnerable to spamming attacks

A US-based security enthusiast has figured out how to send spam to a person's printer from an infected web page.

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A US-based security enthusiast has figured out how to send spam to a person's printer from an infected web page.

Aaron Weaver made the discovery that the world could probably do without, by using a little-known capability found in most web browsers. Using this, Weaver can make a web page launch a print job on just about any printer on a victim's network. The website could print annoying ads on the printer and theoretically issue more dangerous commands, like telling the printer to send a fax, format its hard drive or download new firmware.

Weaver, a security manager in the financial industry, described what he calls "cross site printing" in a research paper on the Ha.ckers.org website.

For a cross-site printing attack to work, a victim would have to visit either a malicious website or a legitimate page that suffers from a cross-site scripting flaw, which is a common type of web programming error. The hacker would then send JavaScript code to the browser that would guess the location of the victim's printer and send it a print job.

Weaver has launched the attack successfully with both Internet Explorer and Firefox browsers. Because the attack only works on network printers, a printer plugged directly into a PC would not be vulnerable.

The attack is possible because most browsers can connect to the networking port used by most printers to look for new print jobs. So by using the browser as a stepping stone, attackers are able to connect with something they should never be able to reach: a printer on the local area network.

While nobody had previously demonstrated this particular hack, Weaver's research is based on two concepts that are well-known to web security researchers: cross-site scripting attacks and vulnerabilities in the way browsers handle the Internet Protocol. "There is no precedent for [this hack]," said Robert Hansen, chief executive at web security consultancy SecTheory and owner of the Ha.ckers.org website. "But ... what he did was marry two different concepts that we've been talking about for a long time."

And if hackers had figured out a way to make printers send out information about their print jobs to the Internet, Weaver's hack could have had even more profound security implications, Hansen said.

Weaver said concerns that his research might unleash a new blight on the Internet caused him to hesitate before publishing his paper and hold off on publishing the complete exploit code.

By Wednesday he'd already received his first request from someone asking to look at his software - someone saying he needed to show it to his manager in order to prove that it was a real issue. Weaver said he suspects the inquiry may have come from a spammer.

So will we see cross-site printer spam flying around our networks anytime soon? Weaver believes there's a good chance of that happening. "Spammers will try anything," he said.

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