.US Harbors Prolific Malicious Link Shortening Service

The top-level domain for the United States — .US — is home to thousands of newly-registered domains tied to a malicious link shortening service that facilitates malware and phishing scams, new research suggests. The findings come close on the heels of a report that identified .US domains as among the most prevalent in phishing attacks over the past year.

Researchers at Infoblox say they’ve been tracking what appears to be a three-year-old link shortening service that is catering to phishers and malware purveyors. Infoblox found the domains involved are typically three to seven characters long, and hosted on bulletproof hosting providers that charge a premium to ignore any abuse or legal complaints. The short domains don’t host any content themselves, but are used to obfuscate the real address of landing pages that try to phish users or install malware.

A graphic describing the operations of a malicious link shortening service that Infoblox has dubbed “Prolific Puma.”

Infoblox says it’s unclear how the phishing and malware landing pages tied to this service are being initially promoted, although they suspect it is mainly through scams targeting people on their phones via SMS. A new report says the company mapped the contours of this link shortening service thanks in part to pseudo-random patterns in the short domains, which all appear on the surface to be a meaningless jumble of letters and numbers.

“This came to our attention because we have systems that detect registrations that use domain name generation algorithms,” said Renee Burton, head of threat intelligence at Infoblox. “We have not found any legitimate content served through their shorteners.”

Infoblox determined that until May 2023, domains ending in .info accounted for the bulk of new registrations tied to the malicious link shortening service, which Infoblox has dubbed “Prolific Puma.” Since then, they found that whoever is responsible for running the service has used .US for approximately 55 percent of the total domains created, with several dozen new malicious .US domains registered daily.

.US is overseen by the National Telecommunications and Information Administration (NTIA), an executive branch agency of the U.S. Department of Commerce. But Uncle Sam has long outsourced the management of .US to various private companies, which have gradually allowed the United States’s top-level domain to devolve into a cesspool of phishing activity.

Or so concludes The Interisle Consulting Group, which gathers phishing data from multiple industry sources and publishes an annual report on the latest trends. As far back as 2018, Interisle found .US domains were the worst in the world for spam, botnet (attack infrastructure for DDOS etc.) and illicit or harmful content.

Interisle’s newest study examined six million phishing reports between May 1, 2022 and April 30, 2023, and identified approximately 30,000 .US phishing domains. Interisle found significant numbers of .US domains were registered to attack some of the United States’ most prominent companies, including Bank of America, Amazon, Apple, AT&T, Citi, Comcast, Microsoft, Meta, and Target. Others were used to impersonate or attack U.S. government agencies.

Under NTIA regulations, domain registrars processing .US domain registrations must take certain steps (PDF) to verify that those customers actually reside in the United States, or else own organizations based in the U.S. However, if one registers a .US domain through GoDaddy — the largest domain registrar and the current administrator of the .US contract — the way one “proves” their U.S. nexus is simply by choosing from one of three pre-selected affirmative responses.

In an age when most domain registrars are automatically redacting customer information from publicly accessible registration records to avoid running afoul of European privacy laws, .US has remained something of an outlier because its charter specifies that all registration records be made public. However, Infoblox said it found more than 2,000 malicious link shortener domains ending in .US registered since October 2023 through NameSilo that have somehow subverted the transparency requirements for the usTLD and converted to private registrations.

“Through our own experience with NameSilo, it is not possible to select private registration for domains in the usTLD through their interface,” Infoblox wrote. “And yet, it was done. Of the total domains with private records, over 99% were registered with NameSilo. At this time, we are not able to explain this behavior.”

NameSilo CEO Kristaps Ronka said the company actively responds to reports about abusive domains, but that it hasn’t seen any abuse reports related to Infoblox’s findings.

“We take down hundreds to thousands of domains, lots of them proactively to combat abuse,” Ronka said. “Our current abuse rate on abuseIQ for example is currently at 0%. AbuseIQ receives reports from countless sources and we are yet to see these ‘Puma’ abuse reports.”

Experts who track domains associated with malware and phishing say even phony information supplied at registration is useful in identifying potentially malicious or phishous domains before they can be used for abuse.

For example, when it was registered through NameSilo in July 2023, the domain 1ox[.]us — like thousands of others — listed its registrant as “Leila Puma” at a street address in Poland, and the email address blackpumaoct33@ukr.net. But according to DomainTools.com, on Oct. 1, 2023 those records were redacted and hidden by NameSilo.

Infoblox notes that the username portion of the email address appears to be a reference to the song October 33 by the Black Pumas, an Austin, Texas based psychedelic soul band. The Black Pumas aren’t exactly a household name, but they did recently have a popular Youtube video that featured a cover of the Kinks song “Strangers,” which included an emotional visual narrative about Ukrainians seeking refuge from the Russian invasion, titled “Ukraine Strangers.” Also, Leila Puma’s email address is at a Ukrainian email provider.

DomainTools shows that hundreds of other malicious domains tied to Prolific Puma previously were registered through NameCheap to a “Josef Bakhovsky” at a different street address in Poland. According to ancestry.com, the anglicized version of this surname — Bakovski — is the traditional name for someone from Bakowce, which is now known as Bakivtsi and is in Ukraine.

This possible Polish and/or Ukrainian connection may or may not tell us something about the “who” behind this link shortening service, but those details are useful for identifying and grouping these malicious short domains. However, even this meager visibility into .US registration data is now under threat.

The NTIA recently published a proposal that would allow registrars to redact all registrant data from WHOIS registration records for .US domains. A broad array of industry groups have filed comments opposing the proposed changes, saying they threaten to remove the last vestiges of accountability for a top-level domain that is already overrun with cybercrime activity.

Infoblox’s Burton says Prolific Puma is remarkable because they’ve been able to facilitate malicious activities for years while going largely unnoticed by the security industry.

“This exposes how persistent the criminal economy can be at a supply chain level,” Burton said. “We’re always looking at the end malware or phishing page, but what we’re finding here is that there’s this middle layer of DNS threat actors persisting for years without notice.”

Infoblox’s full report on Prolific Puma is here.

Phishing Domains Tanked After Meta Sued Freenom

The number of phishing websites tied to domain name registrar Freenom dropped precipitously in the months surrounding a recent lawsuit from social networking giant Meta, which alleged the free domain name provider has a long history of ignoring abuse complaints about phishing websites while monetizing traffic to those abusive domains.

The volume of phishing websites registered through Freenom dropped considerably since the registrar was sued by Meta. Image: Interisle Consulting.

Freenom is the domain name registry service provider for five so-called “country code top level domains” (ccTLDs), including .cf for the Central African Republic; .ga for Gabon; .gq for Equatorial Guinea; .ml for Mali; and .tk for Tokelau.

Freenom has always waived the registration fees for domains in these country-code domains, but the registrar also reserves the right to take back free domains at any time, and to divert traffic to other sites — including adult websites. And there are countless reports from Freenom users who’ve seen free domains removed from their control and forwarded to other websites.

By the time Meta initially filed its lawsuit in December 2022, Freenom was the source of well more than half of all new phishing domains coming from country-code top-level domains. Meta initially asked a court to seal its case against Freenom, but that request was denied. Meta withdrew its December 2022 lawsuit and re-filed it in March 2023.

“The five ccTLDs to which Freenom provides its services are the TLDs of choice for cybercriminals because Freenom provides free domain name registration services and shields its customers’ identity, even after being presented with evidence that the domain names are being used for illegal purposes,” Meta’s complaint charged. “Even after receiving notices of infringement or phishing by its customers, Freenom continues to license new infringing domain names to those same customers.”

Meta pointed to research from Interisle Consulting Group, which discovered in 2021 and again last year that the five ccTLDs operated by Freenom made up half of the Top Ten TLDs most abused by phishers.

Interisle partner Dave Piscitello said something remarkable has happened in the months since the Meta lawsuit.

“We’ve observed a significant decline in phishing domains reported in the Freenom commercialized ccTLDs in months surrounding the lawsuit,” Piscitello wrote on Mastodon. “Responsible for over 60% of phishing domains reported in November 2022, Freenom’s percentage has dropped to under 15%.”

Interisle collects data from 12 major blocklists for spam, malware, and phishing, and it receives phishing-specific data from Spamhaus, Phishtank, OpenPhish and the APWG Ecrime Exchange. The company publishes historical data sets quarterly, both on malware and phishing.

Piscitello said it’s too soon to tell the full impact of the Freenom lawsuit, noting that Interisle’s sources of spam and phishing data all have different policies about when domains are removed from their block lists.

“One of the things we don’t have visibility into is how each of the blocklists determine to remove a URL from their lists,” he said. “Some of them time out [listed domains] after 14 days, some do it after 30, and some keep them forever.”

Freenom did not respond to requests for comment.

This is the second time in as many years that a lawsuit by Meta against a domain registrar has disrupted the phishing industry. In March 2020, Meta sued domain registrar giant Namecheap, alleging cybersquatting and trademark infringement.

The two parties settled the matter in April 2022. While the terms of that settlement have not been disclosed, new phishing domains registered through Namecheap declined more than 50 percent the following quarter, Interisle found.

Phishing attacks using websites registered through Namecheap, before and after the registrar settled a lawsuit with Meta. Image: Interisle Consulting.

Unfortunately, the lawsuits have had little effect on the overall number of phishing attacks and phishing-related domains, which have steadily increased in volume over the years.  Piscitello said the phishers tend to gravitate toward registrars that offer the least resistance and lowest price per domain. And with new top-level domains constantly being introduced, there is rarely a shortage of super low-priced domains.

“The abuse of a new top-level domain is largely the result of one registrar’s portfolio,” Piscitello told KrebsOnSecurity. “Alibaba or Namecheap or another registrar will run a promotion for a cheap domain, and then we’ll see flocking and migration of the phishers to that TLD. It’s like strip mining, where they’ll buy hundreds or thousands of domains, use those in a campaign, exhaust that TLD and then move on to another provider.”

Piscitello said despite the steep drop in phishing domains coming out of Freenom, the alternatives available to phishers are many. After all, there are more than 2,000 accredited domain registrars, not to mention dozens of services that let anyone set up a website for free without even owning a domain.

“There is no evidence that the trend line is even going to level off,” he said. “I think what the Meta lawsuit tells us is that litigation is like giving someone a standing eight count. It temporarily disrupts a process. And in that sense, litigation appears to be working.”