Note: A full-length proof of concept is intentionally not being disclosed in the below advisory.
Greyhound Lines Inc. (owned by FirstGroup America Inc. – a subsidiary of FirstGroup Plc (UK))
Greyhound Lines Inc. (U.S.) provides intercity bus service across North America. It provides a personal ticketing kiosk services via its web and mobile applications for Greyhound customers. These applications help customers manage e-ticketing, mobile check-in, and the program.
Critical vulnerabilities were identified in the Greyhound APIs primarily due to insufficient authentication controls. Exploitation of these can result in the exposure of personally identifiable information (PII) for the customers who had joined the Road Rewards program. Additionally, an attacker can also remotely exploit an internet-exposed web service that hosts account information for Greyhound customers as well as other sensitive information. An attacker could use this vulnerability to gain access unrestricted access and completely take over user accounts belonging to affected members.
As the time of this disclosure, this vulnerability affects at least a million members.
The impact of these discovered vulnerabilities is as follows. When exploited, attackers can perform the following:
Hijack (take over the accounts) of more than a million people’s Greyhound Road Rewards accounts
Use that information to access and update users’ personal information, such as personal addresses and contact information like email addresses and phone numbers
View and update upcoming trips as well as users’ travel preferences (e.g., if a user frequently travels alone)
12/08/2018: Initial discovery
Vendor contacted multiple times, no response
01/23/2019: Issue reported to US-CERT
02/19/2019: FirstGroup Plc made contact via Greyhound support
03/01/2019: Full vulnerability details disclosed to vendor
No vendor follow-up and is no longer responsive (The vulnerabilities are still not fixed)
04/11/2019: Partial details for the vulnerabilities disclosed publicly