eBay-owned PayPal has plugged a vulnerability that potentially allowed thieves to seize control of merchants' online stores and empty the shelves.
The bug – discovered by security researcher Mark Litchfield of Securatary – affected PayPal Manager, which is used to manage PayFlow accounts by people selling stuff online.
PayPal personal accounts were not affected by the vulnerability, and it's understood to be separate to PayPal parent eBay's customer database compromise.
The complex PayPal flaw, documented in a 16-page advisory [PDF], allows an attacker to change a merchant's password and hijack their account to order stuff for free.
Litchfield said he notified PayPal about the bug on 10 May and it was fixed the day after. He praised the security team's prompt response.
In a brief statement, PayPal confirmed to The Register the security hole had been plugged, and that Litchfield had received an award under its bug bounty programme for his efforts:
We can confirm that this bug has been fixed, and we appreciate the contributions that security researchers like Mark Litchfield make to PayPal’s Bug Bounty Program in helping keep PayPal a safer place for our customers. As a reminder, never provide sensitive information, click on suspicious links, or open unknown attachments in email, and ensure you are on a legitimate PayPal site before providing your PayPal credentials. If you suspect questionable activity please report it to firstname.lastname@example.org
Litchfield is building up a track record of uncovering holes in eBay's web infrastructure after previously discovering a separate account hijack flaw in eBay ProStores. ®
Updated to add
A PayPal spokesperson has been in touch to "confirm that there is no evidence that PayPal customer information was compromised".