Password bug let me see shoppers' credit cards in eBay ProStores, claims infosec bod

A serious vulnerability that potentially allowed shoplifters to empty eBay ProStores shops and swipe customer credit cards has been fixed – according to the security researcher who says he found the hole.

Mark Litchfield, an infosec pro at Securatary, told us he discovered a flaw in eBay-owned ProStores that not only opened the door to store account hijackers, but also leaked "full access to all their customers PII [Personally identifiable information] as well as their full credit information in clear text."

ProStores hosts online shops for eBay sellers to use to flog their stuff, and provides a wizard for creating the traders' websites.

"Like the gostorego vulnerability (also eBay), we could shop for free by giving ourselves store credit or gift cards or created our own orders for free," Litchfield toldThe Reg.

After he reported the bug in February, the flaw was fixed, clearing the way for Litchfield to go public [PDF] on March 20. eBay has yet to respond to repeated requests for comment from The Reg – we've been on their case since last week.

Lichfield characterizes the vulnerability as a serious string of blunders that took too long to fix. According to the researcher: in order to gain control of a victim's eBay ProStores site, the attacker must create her own ProStores account – there's a handy 30-day free trial available – and then use that as a springboard to infiltrate the victim's web bazaar.

"In short, it was possible to change the password of another administrator, then you could log in as that user with full administrative access to the store," Litchfied claimed. "With this attack I guess I was more shocked than anything to find the credit card information being displayed back in clear text. If people are buying things online, why would the full card information need to returned in clear text to the administrator?"

ProStores is aimed at small to medium businesses, and was bought by eBay in 2005. The outfit offers inventory management, supplier communication and integration with Quickbooks, Dreamweaver and other tools. Litchfield also claimed there was an XML external entity vulnerability [PDF] in ProStores.

Securatary said it had reported the problem to eBay on 11 February but it was only fixed on 20 March. "The Magento (GoStoreGo) issue I reported which El Reg wrote about was fixed extremely quickly but this attack did not expose credit cards," Litchfield told us. "The ProStores attack was as bad as the GoStoreGo one but for some reason took weeks to fix and this one exposed full credit card information in clear text."

We have asked eBay for comment and will update if and when we hear from the firm. 

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