The payment card giant MasterCard just fixed a glaring error in its domain name server settings that could have allowed anyone to intercept or divert Internet traffic for the company by registering an unused domain name. The misconfiguration persisted for nearly five years until a security researcher spent $300 to register the domain and prevent it from being grabbed by cybercriminals.
A DNS lookup on the domain az.mastercard.com on Jan. 14, 2025 shows the mistyped domain name a22-65.akam.ne.
From June 30, 2020 until January 14, 2025, one of the core Internet servers that MasterCard uses to direct traffic for portions of the mastercard.com network was misnamed. MasterCard.com relies on five shared Domain Name System (DNS) servers at the Internet infrastructure provider Akamai [DNS acts as a kind of Internet phone book, by translating website names to numeric Internet addresses that are easier for computers to manage].
All of the Akamai DNS server names that MasterCard uses are supposed to end in “akam.net” but one of them was misconfigured to rely on the domain “akam.ne.”
This tiny but potentially critical typo was discovered recently by Philippe Caturegli, founder of the security consultancy Seralys. Caturegli said he guessed that nobody had yet registered the domain akam.ne, which is under the purview of the top-level domain authority for the West Africa nation of Niger.
Caturegli said it took $300 and nearly three months of waiting to secure the domain with the registry in Niger. After enabling a DNS server on akam.ne, he noticed hundreds of thousands of DNS requests hitting his server each day from locations around the globe. Apparently, MasterCard wasn’t the only organization that had fat-fingered a DNS entry to include “akam.ne,” but they were by far the largest.
Had he enabled an email server on his new domain akam.ne, Caturegli likely would have received wayward emails directed toward mastercard.com or other affected domains. If he’d abused his access, he probably could have obtained website encryption certificates (SSL/TLS certs) that were authorized to accept and relay web traffic for affected websites. He may even have been able to passively receive Microsoft Windows authentication credentials from employee computers at affected companies.
But the researcher said he didn’t attempt to do any of that. Instead, he alerted MasterCard that the domain was theirs if they wanted it, copying this author on his notifications. A few hours later, MasterCard acknowledged the mistake, but said there was never any real threat to the security of its operations.
“We have looked into the matter and there was not a risk to our systems,” a MasterCard spokesperson wrote. “This typo has now been corrected.”
Meanwhile, Caturegli received a request submitted through Bugcrowd, a program that offers financial rewards and recognition to security researchers who find flaws and work privately with the affected vendor to fix them. The message suggested his public disclosure of the MasterCard DNS error via a post on LinkedIn (after he’d secured the akam.ne domain) was not aligned with ethical security practices, and passed on a request from MasterCard to have the post removed.
MasterCard’s request to Caturegli, a.k.a. “Titon” on infosec.exchange.
Caturegli said while he does have an account on Bugcrowd, he has never submitted anything through the Bugcrowd program, and that he reported this issue directly to MasterCard.
“I did not disclose this issue through Bugcrowd,” Caturegli wrote in reply. “Before making any public disclosure, I ensured that the affected domain was registered to prevent exploitation, mitigating any risk to MasterCard or its customers. This action, which we took at our own expense, demonstrates our commitment to ethical security practices and responsible disclosure.”
Most organizations have at least two authoritative domain name servers, but some handle so many DNS requests that they need to spread the load over additional DNS server domains. In MasterCard’s case, that number is five, so it stands to reason that if an attacker managed to seize control over just one of those domains they would only be able to see about one-fifth of the overall DNS requests coming in.
But Caturegli said the reality is that many Internet users are relying at least to some degree on public traffic forwarders or DNS resolvers like Cloudflare and Google.
“So all we need is for one of these resolvers to query our name server and cache the result,” Caturegli said. By setting their DNS server records with a long TTL or “Time To Live” — a setting that can adjust the lifespan of data packets on a network — an attacker’s poisoned instructions for the target domain can be propagated by large cloud providers.
“With a long TTL, we may reroute a LOT more than just 1/5 of the traffic,” he said.
The researcher said he’d hoped that the credit card giant might thank him, or at least offer to cover the cost of buying the domain.
“We obviously disagree with this assessment,” Caturegli wrote in a follow-up post on LinkedIn regarding MasterCard’s public statement. “But we’ll let you judge— here are some of the DNS lookups we recorded before reporting the issue.”
Caturegli posted this screenshot of MasterCard domains that were potentially at risk from the misconfigured domain.
As the screenshot above shows, the misconfigured DNS server Caturegli found involved the MasterCard subdomain az.mastercard.com. It is not clear exactly how this subdomain is used by MasterCard, however their naming conventions suggest the domains correspond to production servers at Microsoft’s Azure cloud service. Caturegli said the domains all resolve to Internet addresses at Microsoft.
“Don’t be like Mastercard,” Caturegli concluded in his LinkedIn post. “Don’t dismiss risk, and don’t let your marketing team handle security disclosures.”
One final note: The domain akam.ne has been registered previously — in December 2016 by someone using the email address um-i-delo@yandex.ru. The Russian search giant Yandex reports this user account belongs to an “Ivan I.” from Moscow. Passive DNS records from DomainTools.com show that between 2016 and 2018 the domain was connected to an Internet server in Germany, and that the domain was left to expire in 2018.
This is interesting given a comment on Caturegli’s LinkedIn post from an ex-Cloudflare employee who linked to a report he co-authored on a similar typo domain apparently registered in 2017 for organizations that may have mistyped their AWS DNS server as “awsdns-06.ne” instead of “awsdns-06.net.” DomainTools reports that this typo domain also was registered to a Yandex user (playlotto@yandex.ru), and was hosted at the same German ISP — Team Internet (AS61969).
You’ve probably never heard of “16Shop,” but there’s a good chance someone using it has tried to phish you.
A 16Shop phishing page spoofing Apple and targeting Japanese users. Image: Akamai.com.
The international police organization INTERPOL said last week it had shuttered the notorious 16Shop, a popular phishing-as-a-service platform launched in 2017 that made it simple for even complete novices to conduct complex and convincing phishing scams. INTERPOL said authorities in Indonesia arrested the 21-year-old proprietor and one of his alleged facilitators, and that a third suspect was apprehended in Japan.
The INTERPOL statement says the platform sold hacking tools to compromise more than 70,000 users in 43 countries. Given how long 16Shop has been around and how many paying customers it enjoyed over the years, that number is almost certainly highly conservative.
Also, the sale of “hacking tools” doesn’t quite capture what 16Shop was all about: It was a fully automated phishing platform that gave its thousands of customers a series of brand-specific phishing kits to use, and provided the domain names needed to host the phishing pages and receive any stolen credentials.
Security experts investigating 16Shop found the service used an application programming interface (API) to manage its users, an innovation that allowed its proprietors to shut off access to customers who failed to pay a monthly fee, or for those attempting to copy or pirate the phishing kit.
16Shop also localized phishing pages in multiple languages, and the service would display relevant phishing content depending on the victim’s geolocation.
Various 16Shop lures for Apple users in different languages. Image: Akamai.
For example, in 2019 McAfee found that for targets in Japan, the 16Shop kit would also collect Web ID and Card Password, while US victims will be asked for their Social Security Number.
“Depending on location, 16Shop will also collect ID numbers (including Civil ID, National ID, and Citizen ID), passport numbers, social insurance numbers, sort codes, and credit limits,” McAfee wrote.
In addition, 16Shop employed various tricks to help its users’ phishing pages stay off the radar of security firms, including a local “blacklist” of Internet addresses tied to security companies, and a feature that allowed users to block entire Internet address ranges from accessing phishing pages.
The INTERPOL announcement does not name any of the suspects arrested in connection with the 16Shop investigation. However, a number of security firms — including Akamai, McAfee and ZeroFox, previously connected the service to a young Indonesian man named Riswanda Noor Saputra, who sold 16Shop under the hacker handle “Devilscream.”
According to the Indonesian security blog Cyberthreat.id, Saputra admitted being the administrator of 16Shop, but told the publication he handed the project off to others by early 2020.
16Shop documentation instructing operators on how to deploy the kit. Image: ZeroFox.
Nevertheless, Cyberthreat reported that Devilscream was arrested by Indonesian police in late 2021 as part of a collaboration between INTERPOL and the U.S. Federal Bureau of Investigation (FBI). Still, researchers who tracked 16Shop since its inception say Devilscream was not the original proprietor of the phishing platform, and he may not be the last.
It is not uncommon for cybercriminals to accidentally infect their own machines with password-stealing malware, and that is exactly what seems to have happened with one of the more recent administrators of 16Shop.
Constella Intelligence, a data breach and threat actor research platform, now allows users to cross-reference popular cybercrime websites and denizens of these forums with inadvertent malware infections by information-stealing trojans. A search in Constella on 16Shop’s domain name shows that in mid-2022, a key administrator of the phishing service infected their Microsoft Windows desktop computer with the Redline information stealer trojan — apparently by downloading a cracked (and secretly backdoored) copy of Adobe Photoshop.
Redline infections steal gobs of data from the victim machine, including a list of recent downloads, stored passwords and authentication cookies, as well as browser bookmarks and auto-fill data. Those records indicate the 16Shop admin used the nicknames “Rudi” and “Rizki/Rizky,” and maintained several Facebook profiles under these monikers.
It appears this user’s full name (or at least part of it) is Rizky Mauluna Sidik, and they are from Bandung in West Java, Indonesia. One of this user’s Facebook pages says Rizky is the chief executive officer and founder of an entity called BandungXploiter, whose Facebook page indicates it is a group focused mainly on hacking and defacing websites.
A LinkedIn profile for Rizky says he is a backend Web developer in Bandung who earned a bachelor’s degree in information technology in 2020. Mr. Rizky did not respond to requests for comment.