Hacker Netanel Rubin has found a critical remote vulnerability in Ebay's web commerce platform Magento that affects 88,000 shops and allows buyers to purchase anything for free, and compromise credit cards and personal data.
The CheckPoint vulnerability hunter says many tat bazaar stores are still exposed to the bug that allows cheapskates to checkout for free using bogus coupons, or hackers to steal shopper's credentials and cards.
"[It can] lead to complete compromise of any Magento-based store, including credit card information as well as other financial and personal data," Rubin says in an advisory.
"This attack is not limited to any particular plugin or theme.
"All the vulnerabilities are present in the Magento core, and affects any default installation of both Community and Enterprise Editions."
Some 200,000 shops were affected late last week, a number that has since fallen by more than half.
Rubin says vulnerable versions include community 220.127.116.11 and enterprise 18.104.22.168 and is fixed with the patch SUPEE-5344.
He demonstrates in a video how an attacker could buy a theoretical $10,000 watch for nothing using a fake coupon, which he dubs "extreme couponing".
Attackers are now attempting to create fake credentials to hijack shops. Sucuri hacker Daniel Cid says one Russia crime group behind the attacks.
"So far, it is only trying to create a fake admin user inside the Magento database which they will certainly misuse later to take over of the site," Cid says.
"... some groups already have an exploit and are attacking as many sites as they can, and pretty fast."
Rubin has detailed complete technical aspects of the flaw.