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osCommerce v2.3.1 with PayPal website payments standard module v1.0 design vulnerability

Vulnerability Note VU#459446

Original Release Date: 2012-09-18 | Last Revised: 2013-05-15


osCommerce 2.3.1 and possibly other versions with the PayPal website payments standard module is susceptible to a client-side attack that results in an attacker purchasing items without having to pay for them.


It has been reported that osCommerce 2.3.1 using the PayPal website payments standard module 1.0 contains a design flaw that allows an attacker to buy items without having to pay for them. The parameter for the merchant's PayPal email address is controlled on the client-side and not verified by the server. This allows an attacker to change the PayPal email address to one the attacker controls allowing the attacker to purchase items on a website but effectively pay themselves instead of the merchant. Manual verification of website orders with the PayPal transactions would need to be performed to detect this fraud.


An attacker can effectively purchase items without paying the merchant for them.


Apply an Update

osCommerce Online Merchant v2.3.4 and v1.1 of the payment module will be released to address this issue. If you are unable to update, please consider the following workaround.

Enable Encrypted Web Payments in the payment module configuration.

Vendor Information


osCommerce Affected

Notified:  July 18, 2012 Updated: August 24, 2012



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

CVSS Metrics

Group Score Vector
Base 5 AV:N/AC:L/Au:N/C:N/I:P/A:N
Temporal 4 E:POC/RL:U/RC:UC
Environmental 4 CDP:ND/TD:ND/CR:ND/IR:ND/AR:ND



Thanks to Giancarlo Pellegrino of SAP Research for reporting this vulnerability.

This document was written by Jared Allar.

Other Information

CVE IDs: CVE-2012-2991
Date Public: 2012-09-17
Date First Published: 2012-09-18
Date Last Updated: 2013-05-15 19:29 UTC
Document Revision: 23

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