Feeds

E-mail ‘bug’ danger overstated?

Not that it's harmless, mind you

  • alert
  • submit to reddit

The Essential Guide to IT Transformation

We recently came across an InfoWorld.com item suggesting that an HTML 'bug' implanted in spam could be a major boon to malicious hackers. The technique mentioned involves embedding a link to a tiny, one-pixel image on the spammer's server.

When victim retrieves the message, his e-mail client automatically fetches the image off the spammer's server in order to display it in the message window. Since the image is miniscule, the victim never sees it and never suspects that his client is communicating with a remote server.

The logs then tell the spammer which e-mail addys or IPs connected to his server looking for the image, which in turn tells him which e-mail addresses are valid, and thus he keeps them on his victim list.

All this is pretty smarmy; it means that spammers can verify valid e-mail addresses with decent accuracy. The normal defensive techniques of not following any link in a spam message and never replying to the decoy "remove me" address (which, far from getting you removed, only confirms that your address works), would no longer be effective.

It's also possible, with JavaScript or ActiveX, to use this basic technique to launch an involuntary browser session pointing to a malicious site, during which a cookie can be dropped on the victim's drive and with which his moves can be tracked. It would also not be tricky to use the HTML bug to generate a cookie where e-mail HTML is rendered by the browser.

But we're not convinced that the specific technique cited - merely embedding a one-pixel image on the body of a spam message - could give malicious hackers remote access to a network or machine, or anything else that they couldn't get more easily through other means.

However, the possibility is suggested in the InfoWorld piece: "It's just a matter of time [before] someone [can] figure out how to use these things against people or corporations," the paper quotes Sharon Ward, director of enterprise business applications at Hurwitz Group, as saying.

But what can be done, we wonder? Certainly one gets a list of valid IPs out of it; but doing it that way would be a chore, whereas a normal port-scan according to IP ranges can be automated and run completely in the background.

Such HTML bugs would also be useful to garner a list of valid IPs in a particular domain; but there again, tools exist which require less effort to do the same (a reverse DNS scan, for example).

One could also validate e-mail addys this way, but once again, a simple script can do the same with batches of questionable addys, and one need not send anything to the victims unless one wishes. It really seems as if tracking is all this technique is useful for.

So we leave it to the evil ingenuity of The Register's beloved readers. If anyone has a good, original hack using a one-pixel image as described above (resorting to JavaScript and/or ActiveX is cheating), e-mail us at the address above and we'll gladly spread the FUD. ®

Build a business case: developing custom apps

More from The Register

next story
iPad? More like iFAD: We reveal why Apple fell into IBM's arms
But never fear fanbois, you're still lapping up iPhones, Macs
Sonos AXES support for Apple's iOS4 and 5
Want to use your iThing? You can't - it's too old
Philip K Dick 'Nazi alternate reality' story to be made into TV series
Amazon Studios, Ridley Scott firm to produce The Man in the High Castle
Too many IT conferences to cover? MICROSOFT to the RESCUE!
Yet more word of cuts emerges from Redmond
Joe Average isn't worth $10 a year to Mark Zuckerberg
The Social Network deflates the PC resurgence with mobile-only usage prediction
Chips are down at Broadcom: Thousands of workers laid off
Cellphone baseband device biz shuttered
Feel free to BONK on the TUBE, says Transport for London
Plus: Almost NOBODY uses pay-by-bonk on buses - Visa
Amazon says Hachette should lower ebook prices, pay authors more
Oh yeah ... and a 30% cut for Amazon to seal the deal
Twitch rich as Google flicks $1bn hitch switch, claims snitch
Gameplay streaming biz and search king refuse to deny fresh gobble rumors
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.