Title: Payment bypass
Product: WordPress NAB Transact WooCommerce Plugin
Vendor Homepage: https://woocommerce.com/products/nab-transact-direct-post/
Vulnerable Version: 2.1.0
Fixed Version: 2.1.2
CVE Number: CVE-2020-11497
Author: Jack Misiura from The Missing Link
Website: https://www.themissinglink.com.au
Timeline:
2020-03-27 Disclosed to Vendor
2020-03-29 Vendor publishes first fix
2020-04-04 Vendor publishes second fix
2020-08-17 Fix confirmed
2020-08-20 Publication
1. Vulnerability Description
The WordPress NAB Transact WooCommerce plugin does not validate the origin of payment processor status requests, allowing orders to be marked as fully paid by issuing a specially crafted GET request during the ordering workflow.
2. PoC
When presented with a payment screen, instead of submitting payment information, issue the following GET request to the site:
https://example-site.com/?wc-api=WC_Gateway_Nab_Direct_Post&order=XXXX&key= wc_order_YYYYY&is_crn=0&txnid=ZZZZZ&refid=WooCommerceXXXX&rescode=00&restext=Approved
Where XXXX is the order number and YYYY is the order code which have been present before during the workflow. If these are not presented, submit invalid payment information and get a declined message. Now brute-force the order number which is sequential. Doing so will mark any existing pending orders as fully paid.
3. Solution
The vendor provides an updated version (2.1.2) which should be installed immediately.
4. Advisory URL
https://www.themissinglink.com.au/security-advisories
Jack Misiura
Application Security Consultant
a
9‑11 Dickson Avenue
Artarmon
NSW
2064
p
1300 865 865
os
+61 2 8436 8585
w
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