Russian serfs paid $3 a day to break CAPTCHAs

Semi-automated attack or chain-mail gang


Why should miscreants bother to develop cutting edge programming techniques when they can pay $3 to somebody to set up spam-ready webmail accounts on their behalf? Evidence has emerged that people as well as malware are being used to defeat CAPTCHAs, challenge-response systems that are often used to stop the automatic creation of webmail accounts by spammers.

CAPTCHAs typically help ensure that online accounts can't be created until a user correctly identifies letters depicted in an image. The tactic is designed to frustrate the use of automated sign-up tools by spammers and other miscreants.

Over recent months security firms have reported that first the Windows Live CAPTCHA used by Hotmail, and later the equivalent system at Gmail, have been broken by automated attacks.

Obtaining a working Gmail account has a number of advantages for spammers. As well as gaining access to Google's services in general, spammers receive an address whose domain is highly unlikely to be blacklisted, helping them defeat one aspect of anti-spam defences. Gmail also has the benefit of being free to use.

An analysis of spam trends in February 2008 by net security firm MessageLabs revealed that 4.6 per cent of all spam originates from web mail-based services.

The proportion of spam from Gmail increased two-fold from 1.3 per cent in January to 2.6 per cent in February, most of which spamvertised skin-flick websites. Yahoo! Mail was the most abused web mail service, responsible for sending 88.7 per cent of all web mail-based spam.

The idea that automated tools have been used by spammers to set up these webmail accounts has become, if not the conventional wisdom, then at least a working hypothesis in security circles of late.

However a senior engineer at Google has stepped forward to cast doubt on these reports.

Brad Taylor, a Google software engineer, said internal evidence suggests that low-paid laborers in third-world countries (rather than compromised PCs) are being used to register accounts that are subsequently used to send spam.

"You can see it is clearly done by humans," Taylor told the New York Times . "There are patterns in the rate we find bogus accounts, like at night time and when people get off work" in particular locations around the world.

Taylor conceded that software might be used to partially automate the process - with bots signing-up for accounts before sending the puzzles to real people - but maintains that the CAPTCHA process remains effective.

Google's contention that low-wage workers are been paid to break watchers is supported by anecdotal evidence unearthed by Websense, which has been active in researching the issue over recent months. The firm found Russian language documents instructing modern day serfs on the art of CAPTCHA breaking.

"If you are unable to recognize a picture or she is not loaded (picture appears black, empty picture), just press Enter. In no case do not enter random characters! If there is delay in downloading images, exit from your account, refresh the page and go again," the documents, found on a website and translated into English, state.

The documents go on to say that CAPTCHA-busters are paid a minimum of $3 a day.

Even if miscreants need human involvement in breaking CAPTCHAs right now this might not always be the case. The solutions to solve puzzles might be fed back to make CAPTCHA-busting algorithms smarter, MessageLabs warns. It said that focusing on whether miscreants are an algorithm, a 'mechanical turk', or combination of the two to break CAPTCHAs misses the bigger point that the approach no longer provides a reliable security mechanism to protect email services from abuse. ®

Similar topics

Broader topics


Other stories you might like

  • North Korea pulled in $400m in cryptocurrency heists last year – report

    Plus: FIFA 22 players lose their identity and Texas gets phony QR codes

    In brief Thieves operating for the North Korean government made off with almost $400m in digicash last year in a concerted attack to steal and launder as much currency as they could.

    A report from blockchain biz Chainalysis found that attackers were going after investment houses and currency exchanges in a bid to purloin funds and send them back to the Glorious Leader's coffers. They then use mixing software to make masses of micropayments to new wallets, before consolidating them all again into a new account and moving the funds.

    Bitcoin used to be a top target but Ether is now the most stolen currency, say the researchers, accounting for 58 per cent of the funds filched. Bitcoin accounted for just 20 per cent, a fall of more than 50 per cent since 2019 - although part of the reason might be that they are now so valuable people are taking more care with them.

    Continue reading
  • Tesla Full Self-Driving videos prompt California's DMV to rethink policy on accidents

    Plus: AI systems can identify different chess players by their moves and more

    In brief California’s Department of Motor Vehicles said it’s “revisiting” its opinion of whether Tesla’s so-called Full Self-Driving feature needs more oversight after a series of videos demonstrate how the technology can be dangerous.

    “Recent software updates, videos showing dangerous use of that technology, open investigations by the National Highway Traffic Safety Administration, and the opinions of other experts in this space,” have made the DMV think twice about Tesla, according to a letter sent to California’s Senator Lena Gonzalez (D-Long Beach), chair of the Senate’s transportation committee, and first reported by the LA Times.

    Tesla isn’t required to report the number of crashes to California’s DMV unlike other self-driving car companies like Waymo or Cruise because it operates at lower levels of autonomy and requires human supervision. But that may change after videos like drivers having to take over to avoid accidentally swerving into pedestrians crossing the road or failing to detect a truck in the middle of the road continue circulating.

    Continue reading
  • Alien life on Super-Earth can survive longer than us due to long-lasting protection from cosmic rays

    Laser experiments show their magnetic fields shielding their surfaces from radiation last longer

    Life on Super-Earths may have more time to develop and evolve, thanks to their long-lasting magnetic fields protecting them against harmful cosmic rays, according to new research published in Science.

    Space is a hazardous environment. Streams of charged particles traveling at very close to the speed of light, ejected from stars and distant galaxies, bombard planets. The intense radiation can strip atmospheres and cause oceans on planetary surfaces to dry up over time, leaving them arid and incapable of supporting habitable life. Cosmic rays, however, are deflected away from Earth, however, since it’s shielded by its magnetic field.

    Now, a team of researchers led by the Lawrence Livermore National Laboratory (LLNL) believe that Super-Earths - planets that are more massive than Earth but less than Neptune - may have magnetic fields too. Their defensive bubbles, in fact, are estimated to stay intact for longer than the one around Earth, meaning life on their surfaces will have more time to develop and survive.

    Continue reading

Biting the hand that feeds IT © 1998–2022