Pierluigi Paganini May 30, 2013

The PayPal Users Reports System is a precious tool for PayPal customers used to track their transaction helping them to manage their business. In his last post Nir described critical vulnerabilities  in the Paypal Reporting system that allow an attacker to steal sensitive data (shipping address Email addresses, Phone Number, Item name, Item Amount, Full name, Transaction ID, Invoice ID,  Transaction, Subject, Account ID, Paypal Reference ID etc.) of any PayPal account.

The key of the Goldshlager’s exploits is in a third-party application used by  PayPal Users Reports System for report rendering. PayPal Users Reports System uses the application Actuate iPortal to compose user’s reports, the researcher focused his test on a trial version of the software available on the official web site for testing purpose.

Nir Goldshlager dissected the source code of the iPortal app discovering a file named getfolderitems.do that allowed him to access user’s data without any authentication mechanism.

Getfolderitems.do file contains an ID parameter of 7-8 numeric characters which can be manipulated by an attacker to get the secret token id associate to user’s account . If the attacker manipulates the id parameter (getfolderitems.do?id=392302), then PayPal would expose the secret token of the victim, once obtained the ID it is possible to use the folder parameter to access to victim’s data.

Nir Goldshlager discovered that PayPal rejects any requests to access the users’ folders through getfolderitems.do

getfolderitems.do?folder=/users/

allowing only requests that contain  secret token of the “victim.”

getfolderitems.do?folder=/users/9k1mvk2s10almQ9PM/

The complete url is  URL:

https://business.paypal.com/acweb/getfolderitems.do?folder=/users/tokenidofthevictim/ ,

where tokenidofthevictim is the secret token of the victim.

Nir has exploited the vulnerability just for a proof of concept, at the moment PayPal has already fixed it, during PayPal’s bug bounty program, the expert located numerous vulnerabilities in the Iportal application for this reason PayPal just decided to review of its use.

As always I would like to go beyond a simple article raising a reflection on what has been shown by Nir. PayPal is properly considered one of the most secure corporate, and the rapid resolution of the this bug is the proof, however, a flaw in a third-party application has endangered its users’ information.

The attack has to reflect on the need to evaluate each component of a system that we are going to deploy, a vulnerability in a third part module could compromise the entire security chain. It should also be noted that with increasing frequency are used third-party applications or processes for secure authorization (e.g. OAuth) on the portals of which little is known.
The security of a system is determined by the security of each component and the manner in which they are assembled.

Pierluigi Paganini

(Security Affairs – Hacking)