Pierluigi Paganini January 16, 2019

A critical flaw in online flight ticket booking system developed by Amadeus could impact almost half of the fight travelers of 141 airlines around the world

A critical flaw in online flight ticket booking system developed by Amadeus could be exploited by a remote attacker to access and modify travel details and claim his frequent flyer miles. The flaw was discovered by the Israeli security researcher Noam Rotem while he was booking a flight on the Israeli airline ELAL,

It has been estimated that the vulnerability could impact almost half of the fight travelers of 141 airlines around the world, including United Airlines, Lufthansa and Air Canada.

The attacker just needs to know the victim’s PNR (Passenger Name Record) number to exploit the vulnerability.

“Hacker and Activist Noam Rotem, working with Safety Detective research lab, was shocked when he recently discovered a major vulnerability affecting nearly half of all airlines worldwide. While booking a flight with Israeli national carrier ELAL, he came across a significant security breach that allows anyone to access and change private information on flight bookings.” reads a post published by the expert.

“The same breach was then discovered to include 44% of the international carriers market, potentially affecting tens of millions of travelers.”

Once a customer has booked a flight with ELAL, he will receive a PNR number and a unique link that could be used to check the booking and data associated with the PNR.

The researcher analyzed the link and discovered that changing the value of the “RULE_SOURCE_1_ID” parameter in the link using the PNR number of other users would see the booking information associated with their accounts.

Rotem also demonstrated that using the booking information (i.e. booking ID and last name of the customer) it is possible to access the user’s ELAL account and claim frequent flyer miles to a personal account and perform other operations.

“With the PNR and customer name at our disposal, we were able to log into ELAL’s customer portal and make changes, claim frequent flyer miles to a personal account, assign seats and meals, and update the customer’s email and phone number, which could then be used to cancel/change flight reservation via customer service.” continues the post.

“Though the security breach requires knowledge of the PNR code, ELAL sends these codes via unencrypted email, and many people even share them on Facebook or Instagram. But that’s just the tip of the iceberg,”

Rotem also discovered that the Amadeus portal was not implementing any brute-force protection allowing attackers to enumerate all active PNR numbers of customers of any airline website using Amadeus.

“After running a small and non-threatening script to check for any brute-force protections, none of which were found, we were able to find PNRs of random customers, which included all of their personal information,” continues the expert.

Below a video PoC published by the expert, he used a simple script to find active numbers in Amadeus.

Rotem notified the issue to ELAL, Amadeus has quickly fixed the vulnerability.

Pierluigi Paganini

(SecurityAffairs – hacking, flight ticket booking system)

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