Inside a Dark Adtech Empire Fed by Fake CAPTCHAs

Late last year, security researchers made a startling discovery: Kremlin-backed disinformation campaigns were bypassing moderation on social media platforms by leveraging the same malicious advertising technology that powers a sprawling ecosystem of online hucksters and website hackers. A new report on the fallout from that investigation finds this dark ad tech industry is far more resilient and incestuous than previously known.

In November 2024, researchers at the security firm Qurium published an investigation into “Doppelganger,” a disinformation network that promotes pro-Russian narratives and infiltrates Europe’s media landscape by pushing fake news through a network of cloned websites.

Doppelganger campaigns use specialized links that bounce the visitor’s browser through a long series of domains before the fake news content is served. Qurium found Doppelganger relies on a sophisticated “domain cloaking” service, a technology that allows websites to present different content to search engines compared to what regular visitors see. The use of cloaking services helps the disinformation sites remain online longer than they otherwise would, while ensuring that only the targeted audience gets to view the intended content.

Qurium discovered that Doppelganger’s cloaking service also promoted online dating sites, and shared much of the same infrastructure with VexTrio, which is thought to be the oldest malicious traffic distribution system (TDS) in existence. While TDSs are commonly used by legitimate advertising networks to manage traffic from disparate sources and to track who or what is behind each click, VexTrio’s TDS largely manages web traffic from victims of phishing, malware, and social engineering scams.

BREAKING BAD

Digging deeper, Qurium noticed Doppelganger’s cloaking service used an Internet provider in Switzerland as the first entry point in a chain of domain redirections. They also noticed the same infrastructure hosted a pair of co-branded affiliate marketing services that were driving traffic to sketchy adult dating sites: LosPollos[.]com and TacoLoco[.]co.

The LosPollos ad network incorporates many elements and references from the hit series “Breaking Bad,” mirroring the fictional “Los Pollos Hermanos” restaurant chain that served as a money laundering operation for a violent methamphetamine cartel.

Affiliates who sign up with LosPollos are given JavaScript-heavy “smartlinks” that drive traffic into the VexTrio TDS, which in turn distributes the traffic among a variety of advertising partners, including dating services, sweepstakes offers, bait-and-switch mobile apps, financial scams and malware download sites.

LosPollos affiliates typically stitch these smart links into WordPress websites that have been hacked via known vulnerabilities, and those affiliates will earn a small commission each time an Internet user referred by any of their hacked sites falls for one of these lures.

According to Qurium, TacoLoco is a traffic monetization network that uses deceptive tactics to trick Internet users into enabling “push notifications,” a cross-platform browser standard that allows websites to show pop-up messages which appear outside of the browser. For example, on Microsoft Windows systems these notifications typically show up in the bottom right corner of the screen — just above the system clock.

In the case of VexTrio and TacoLoco, the notification approval requests themselves are deceptive — disguised as “CAPTCHA” challenges designed to distinguish automated bot traffic from real visitors. For years, VexTrio and its partners have successfully tricked countless users into enabling these site notifications, which are then used to continuously pepper the victim’s device with a variety of phony virus alerts and misleading pop-up messages.

According to a December 2024 annual report from GoDaddy, nearly 40 percent of compromised websites in 2024 redirected visitors to VexTrio via LosPollos smartlinks.

ADSPRO AND TEKNOLOGY

On November 14, 2024, Qurium published research to support its findings that LosPollos and TacoLoco were services operated by Adspro Group, a company registered in the Czech Republic and Russia, and that Adspro runs its infrastructure at the Swiss hosting providers C41 and Teknology SA.

Qurium noted the LosPollos and TacoLoco sites state that their content is copyrighted by ByteCore AG and SkyForge Digital AG, both Swiss firms that are run by the owner of Teknology SA, Giulio Vitorrio Leonardo Cerutti. Further investigation revealed LosPollos and TacoLoco were apps developed by a company called Holacode, which lists Cerutti as its CEO.

The apps marketed by Holacode include numerous VPN services, as well as one called Spamshield that claims to stop unwanted push notifications. But in January, Infoblox said they tested the app on their own mobile devices, and found it hides the user’s notifications, and then after 24 hours stops hiding them and demands payment. Spamshield subsequently changed its developer name from Holacode to ApLabz, although Infoblox noted that the Terms of Service for several of the rebranded ApLabz apps still referenced Holacode in their terms of service.

Incredibly, Cerutti threatened to sue me for defamation before I’d even uttered his name or sent him a request for comment (Cerutti sent the unsolicited legal threat back in January after his company and my name were merely tagged in an Infoblox post on LinkedIn about VexTrio).

Asked to comment on the findings by Qurium and Infoblox, Cerutti vehemently denied being associated with VexTrio. Cerutti asserted that his companies all strictly adhere to the regulations of the countries in which they operate, and that they have been completely transparent about all of their operations.

“We are a group operating in the advertising and marketing space, with an affiliate network program,” Cerutti responded. “I am not [going] to say we are perfect, but I strongly declare we have no connection with VexTrio at all.”

“Unfortunately, as a big player in this space we also get to deal with plenty of publisher fraud, sketchy traffic, fake clicks, bots, hacked, listed and resold publisher accounts, etc, etc.,” Cerutti continued. “We bleed lots of money to such malpractices and conduct regular internal screenings and audits in a constant battle to remove bad traffic sources. It is also a highly competitive space, where some upstarts will often play dirty against more established mainstream players like us.”

Working with Qurium, researchers at the security firm Infoblox released details about VexTrio’s infrastructure to their industry partners. Just four days after Qurium published its findings, LosPollos announced it was suspending its push monetization service. Less than a month later, Adspro had rebranded to Aimed Global.

A REVEALING PIVOT

In March 2025, researchers at GoDaddy chronicled how DollyWay — a malware strain that has consistently redirected victims to VexTrio throughout its eight years of activity — suddenly stopped doing that on November 20, 2024. Virtually overnight, DollyWay and several other malware families that had previously used VexTrio began pushing their traffic through another TDS called Help TDS.

Digging further into historical DNS records and the unique code scripts used by the Help TDS, Infoblox determined it has long enjoyed an exclusive relationship with VexTrio (at least until LosPollos ended its push monetization service in November).

In a report released today, Infoblox said an exhaustive analysis of the JavaScript code, website lures, smartlinks and DNS patterns used by VexTrio and Help TDS linked them with at least four other TDS operators (not counting TacoLoco). Those four entities — Partners House, BroPush, RichAds and RexPush — are all Russia-based push monetization programs that pay affiliates to drive signups for a variety of schemes, but mostly online dating services.

“As Los Pollos push monetization ended, we’ve seen an increase in fake CAPTCHAs that drive user acceptance of push notifications, particularly from Partners House,” the Infoblox report reads. “The relationship of these commercial entities remains a mystery; while they are certainly long-time partners redirecting traffic to one another, and they all have a Russian nexus, there is no overt common ownership.”

Renee Burton, vice president of threat intelligence at Infoblox, said the security industry generally treats the deceptive methods used by VexTrio and other malicious TDSs as a kind of legally grey area that is mostly associated with less dangerous security threats, such as adware and scareware.

But Burton argues that this view is myopic, and helps perpetuate a dark adtech industry that also pushes plenty of straight-up malware, noting that hundreds of thousands of compromised websites around the world every year redirect victims to the tangled web of VexTrio and VexTrio-affiliate TDSs.

“These TDSs are a nefarious threat, because they’re the ones you can connect to the delivery of things like information stealers and scams that cost consumers billions of dollars a year,” Burton said. “From a larger strategic perspective, my takeaway is that Russian organized crime has control of malicious adtech, and these are just some of the many groups involved.”

WHAT CAN YOU DO?

As KrebsOnSecurity warned way back in 2020, it’s a good idea to be very sparing in approving notifications when browsing the Web. In many cases these notifications are benign, but as we’ve seen there are numerous dodgy firms that are paying site owners to install their notification scripts, and then reselling that communications pathway to scammers and online hucksters.

If you’d like to prevent sites from ever presenting notification requests, all of the major browser makers let you do this — either across the board or on a per-website basis. While it is true that blocking notifications entirely can break the functionality of some websites, doing this for any devices you manage on behalf of your less tech-savvy friends or family members might end up saving everyone a lot of headache down the road.

To modify site notification settings in Mozilla Firefox, navigate to Settings, Privacy & Security, Permissions, and click the “Settings” tab next to “Notifications.” That page will display any notifications already permitted and allow you to edit or delete any entries. Tick the box next to “Block new requests asking to allow notifications” to stop them altogether.

In Google Chrome, click the icon with the three dots to the right of the address bar, scroll all the way down to Settings, Privacy and Security, Site Settings, and Notifications. Select the “Don’t allow sites to send notifications” button if you want to banish notification requests forever.

In Apple’s Safari browser, go to Settings, Websites, and click on Notifications in the sidebar. Uncheck the option to “allow websites to ask for permission to send notifications” if you wish to turn off notification requests entirely.

.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.

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.

Why is .US Being Used to Phish So Many of Us?

Domain names ending in “.US” — the top-level domain for the United States — are among the most prevalent in phishing scams, new research shows. This is noteworthy because .US is overseen by the U.S. government, which is frequently the target of phishing domains ending in .US. Also, .US domains are only supposed to be available to U.S. citizens and to those who can demonstrate that they have a physical presence in the United States.

.US is the “country code top-level domain” or ccTLD of the United States. Most countries have their own ccTLDs: .MX for Mexico, for example, or .CA for Canada. But few other major countries in the world have anywhere near as many phishing domains each year as .US.

That’s according to The Interisle Consulting Group, which gathers phishing data from multiple industry sources and publishes an annual report on the latest trends. Interisle’s newest study examined six million phishing reports between May 1, 2022 and April 30, 2023, and found 30,000 .US phishing domains.

.US is overseen by the National Telecommunications and Information Administration (NTIA), an executive branch agency of the U.S. Department of Commerce. However, NTIA currently contracts out the management of the .US domain to GoDaddy, by far the world’s largest domain registrar.

Under NTIA regulations, the administrator of the .US registry must take certain steps to verify that their customers actually reside in the United States, or own organizations based in the U.S. But Interisle found that whatever GoDaddy was doing to manage that vetting process wasn’t working.

“The .US ‘nexus’ requirement theoretically limits registrations to parties with a national connection, but .US had very high numbers of phishing domains,” Interisle wrote. “This indicates a possible problem with the administration or application of the nexus requirements.”

Dean Marks is emeritus executive director for a group called the Coalition for Online Accountability, which has been critical of the NTIA’s stewardship of .US. Marks says virtually all European Union member state ccTLDs that enforce nexus restrictions also have massively lower levels of abuse due to their policies and oversight.

“Even very large ccTLDs, like .de for Germany — which has a far larger market share of domain name registrations than .US — have very low levels of abuse, including phishing and malware,” Marks told KrebsOnSecurity. “In my view, this situation with .US should not be acceptable to the U.S. government overall, nor to the US public.”

Marks said there are very few phishing domains ever registered in other ccTLDs that also restrict registrations to their citizens, such as .HU (Hungary), .NZ (New Zealand), and .FI (Finland), where a connection to the country, a proof of identity, or evidence of incorporation are required.

“Or .LK (Sri Lanka), where the acceptable use policy includes a ‘lock and suspend’ if domains are reported for suspicious activity,” Marks said. “These ccTLDs make a strong case for validating domain registrants in the interest of public safety.”

Sadly, .US has been a cesspool of phishing activity for many years. 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. Back then, .US was being operated by a different contractor.

In response to questions from KrebsOnSecurity, GoDaddy said all .US registrants must certify that they meet the NTIA’s nexus requirements. But this appears to be little more than an affirmative response that is already pre-selected for all new registrants.

Attempting to register a .US domain through GoDaddy, for example, leads to a U.S. Registration Information page that auto-populates the nexus attestation field with the response, “I am a citizen of the US.” Other options include, “I am a permanent resident of the US,” and “My primary domicile is in the US.” It currently costs just $4.99 to obtain a .US domain through GoDaddy.

GoDaddy said it also conducts a scan of selected registration request information, and conducts “spot checks” on registrant information.

“We conduct regular reviews, per policy, of registration data within the Registry database to determine Nexus compliance with ongoing communications to registrars and registrants,” the company said in a written statement.

GoDaddy says it “is committed to supporting a safer online environment and proactively addressing this issue by assessing it against our own anti-abuse mitigation system.”

“We stand against DNS abuse in any form and maintain multiple systems and protocols to protect all the TLDs we operate,” the statement continued. “We will continue to work with registrars, cybersecurity firms and other stakeholders to make progress with this complex challenge.”

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.

“Ironically, at least 109 of the .US domains in our data were used to attack the United States government, specifically the United States Postal Service and its customers,” Interisle wrote. “.US domains were also used to attack foreign government operations: six .US domains were used to attack Australian government services, six attacked Great’s Britain’s Royal Mail, one attacked Canada Post, and one attacked the Denmark Tax Authority.”

The NTIA recently published a proposal that would allow GoDaddy to redact registrant data from WHOIS registration records. The current charter for .US specifies that all .US registration records be public.

Interisle argues that without more stringent efforts to verify a United States nexus for new .US domain registrants, the NTIA’s proposal will make it even more difficult to identify phishers and verify registrants’ identities and nexus qualifications.

In a written statement, the NTIA said DNS abuse is a priority issue for the agency, and that NTIA supports “evidence-based policymaking.”

“We look forward to reviewing the report and will engage with our contractor for the .US domain on steps that we can take not only to address phishing, but the other forms of DNS abuse as well,” the statement reads.

Interisle sources its phishing data from several places, including the Anti-Phishing Working Group (APWG), OpenPhish, PhishTank, and Spamhaus. For more phishing facts, see Interisle’s 2023 Phishing Landscape report (PDF).’

Update, Sept. 5, 1:44 p.m. ET: Updated story with statement provided today by the NTIA.