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Ukraine has seen nearly one-fifth of its Internet space come under Russian control or sold to Internet address brokers since February 2022, a new study finds. The analysis indicates large chunks of Ukrainian Internet address space are now in the hands of shadowy proxy and anonymity services that are nested at some of America’s largest Internet service providers (ISPs).
The findings come in a report examining how the Russian invasion has affected Ukraine’s domestic supply of Internet Protocol Version 4 (IPv4) addresses. Researchers at Kentik, a company that measures the performance of Internet networks, found that while a majority of ISPs in Ukraine haven’t changed their infrastructure much since the war began in 2022, others have resorted to selling swathes of their valuable IPv4 address space just to keep the lights on.
For example, Ukraine’s incumbent ISP Ukrtelecom is now routing just 29 percent of the IPv4 address ranges that the company controlled at the start of the war, Kentik found. Although much of that former IP space remains dormant, Ukrtelecom told Kentik’s Doug Madory they were forced to sell many of their address blocks “to secure financial stability and continue delivering essential services.”
“Leasing out a portion of our IPv4 resources allowed us to mitigate some of the extraordinary challenges we have been facing since the full-scale invasion began,” Ukrtelecom told Madory.
Madory found much of the IPv4 space previously allocated to Ukrtelecom is now scattered to more than 100 providers globally, particularly at three large American ISPs — Amazon (AS16509), AT&T (AS7018), and Cogent (AS174).
Another Ukrainian Internet provider — LVS (AS43310) — in 2022 was routing approximately 6,000 IPv4 addresses across the nation. Kentik learned that by November 2022, much of that address space had been parceled out to over a dozen different locations, with the bulk of it being announced at AT&T.
IP addresses routed over time by Ukrainian provider LVS (AS43310) shows a large chunk of it being routed by AT&T (AS7018). Image: Kentik.
Ditto for the Ukrainian ISP TVCOM, which currently routes nearly 15,000 fewer IPv4 addresses than it did at the start of the war. Madory said most of those addresses have been scattered to 37 other networks outside of Eastern Europe, including Amazon, AT&T, and Microsoft.
The Ukrainian ISP Trinity (AS43554) went offline in early March 2022 during the bloody siege of Mariupol, but its address space eventually began showing up in more than 50 different networks worldwide. Madory found more than 1,000 of Trinity’s IPv4 addresses suddenly appeared on AT&T’s network.
Why are all these former Ukrainian IP addresses being routed by U.S.-based networks like AT&T? According to spur.us, a company that tracks VPN and proxy services, nearly all of the address ranges identified by Kentik now map to commercial proxy services that allow customers to anonymously route their Internet traffic through someone else’s computer.
From a website’s perspective, the traffic from a proxy network user appears to originate from the rented IP address, not from the proxy service customer. These services can be used for several business purposes, such as price comparisons, sales intelligence, web crawlers and content-scraping bots. However, proxy services also are massively abused for hiding cybercrime activity because they can make it difficult to trace malicious traffic to its original source.
IPv4 address ranges are always in high demand, which means they are also quite valuable. There are now multiple companies that will pay ISPs to lease out their unwanted or unused IPv4 address space. Madory said these IPv4 brokers will pay between $100-$500 per month to lease a block of 256 IPv4 addresses, and very often the entities most willing to pay those rental rates are proxy and VPN providers.
A cursory review of all Internet address blocks currently routed through AT&T — as seen in public records maintained by the Internet backbone provider Hurricane Electric — shows a preponderance of country flags other than the United States, including networks originating in Hungary, Lithuania, Moldova, Mauritius, Palestine, Seychelles, Slovenia, and Ukraine.
AT&T’s IPv4 address space seems to be routing a great deal of proxy traffic, including a large number of IP address ranges that were until recently routed by ISPs in Ukraine.
Asked about the apparent high incidence of proxy services routing foreign address blocks through AT&T, the telecommunications giant said it recently changed its policy about originating routes for network blocks that are not owned and managed by AT&T. That new policy, spelled out in a February 2025 update to AT&T’s terms of service, gives those customers until Sept. 1, 2025 to originate their own IP space from their own autonomous system number (ASN), a unique number assigned to each ISP (AT&T’s is AS7018).
“To ensure our customers receive the best quality of service, we changed our terms for dedicated internet in February 2025,” an AT&T spokesperson said in an emailed reply. “We no longer permit static routes with IP addresses that we have not provided. We have been in the process of identifying and notifying affected customers that they have 90 days to transition to Border Gateway Protocol routing using their own autonomous system number.”
Ironically, the co-mingling of Ukrainian IP address space with proxy providers has resulted in many of these addresses being used in cyberattacks against Ukraine and other enemies of Russia. Earlier this month, the European Union sanctioned Stark Industries Solutions Inc., an ISP that surfaced two weeks before the Russian invasion and quickly became the source of large-scale DDoS attacks and spear-phishing attempts by Russian state-sponsored hacking groups. A deep dive into Stark’s considerable address space showed some of it was sourced from Ukrainian ISPs, and most of it was connected to Russia-based proxy and anonymity services.
According to Spur, the proxy service IPRoyal is the current beneficiary of IP address blocks from several Ukrainian ISPs profiled in Kentik’s report. Customers can chose proxies by specifying the city and country they would to proxy their traffic through. Image: Trend Micro.
Spur’s Chief Technology Officer Riley Kilmer said AT&T’s policy change will likely force many proxy services to migrate to other U.S. providers that have less stringent policies.
“AT&T is the first one of the big ISPs that seems to be actually doing something about this,” Kilmer said. “We track several services that explicitly sell AT&T IP addresses, and it will be very interesting to see what happens to those services come September.”
Still, Kilmer said, there are several other large U.S. ISPs that continue to make it easy for proxy services to bring their own IP addresses and host them in ranges that give the appearance of residential customers. For example, Kentik’s report identified former Ukrainian IP ranges showing up as proxy services routed by Cogent Communications (AS174), a tier-one Internet backbone provider based in Washington, D.C.
Kilmer said Cogent has become an attractive home base for proxy services because it is relatively easy to get Cogent to route an address block.
“In fairness, they transit a lot of traffic,” Kilmer said of Cogent. “But there’s a reason a lot of this proxy stuff shows up as Cogent: Because it’s super easy to get something routed there.”
Cogent declined a request to comment on Kentik’s findings.
One of the most notorious providers of abuse-friendly “bulletproof” web hosting for cybercriminals has started routing its operations through networks run by the Russian antivirus and security firm Kaspersky Lab, KrebsOnSecurity has learned.
Security experts say the Russia-based service provider Prospero OOO (the triple O is the Russian version of “LLC”) has long been a persistent source of malicious software, botnet controllers, and a torrent of phishing websites. Last year, the French security firm Intrinsec detailed Prospero’s connections to bulletproof services advertised on Russian cybercrime forums under the names Securehost and BEARHOST.
The bulletproof hosting provider BEARHOST. This screenshot has been machine-translated from Russian. Image: Ke-la.com.
Bulletproof hosts are so named when they earn or cultivate a reputation for ignoring legal demands and abuse complaints. And BEARHOST has been cultivating its reputation since at least 2019.
“If you need a server for a botnet, for malware, brute, scan, phishing, fakes and any other tasks, please contact us,” BEARHOST’s ad on one forum advises. “We completely ignore all abuses without exception, including SPAMHAUS and other organizations.”
Intrinsec found Prospero has courted some of Russia’s nastiest cybercrime groups, hosting control servers for multiple ransomware gangs over the past two years. Intrinsec said its analysis showed Prospero frequently hosts malware operations such as SocGholish and GootLoader, which are spread primarily via fake browser updates on hacked websites and often lay the groundwork for more serious cyber intrusions — including ransomware.
A fake browser update page pushing mobile malware. Image: Intrinsec.
BEARHOST prides itself on the ability to evade blocking by Spamhaus, an organization that many Internet service providers around the world rely on to help identify and block sources of malware and spam. Earlier this week, Spamhaus said it noticed that Prospero was suddenly connecting to the Internet by routing through networks operated by Kaspersky Lab in Moscow.
Update, March 1, 9:43 a.m. ET: In a written statement, Kaspersky said it is aware of the public claim about the company allegedly providing services to a “bulletproof” web hosting provider. Here is their full statement:
“Kaspersky denies these claims as the company does not work and has never worked with the service provider in question. The routing through networks operated by Kaspersky doesn’t by default mean provision of the company’s services, as Kaspersky’s automatic system (AS) path might appear as a technical prefix in the network of telecom providers the company works with and provides its DDoS services.”
“Kaspersky pays great attention to conducting business ethically and ensuring that its solutions are used for their original purpose of providing cybersecurity protection. The company is currently investigating the situation to inform the company whose network could have served as a transit for a “bulletproof” web hosting provider so that the former takes the necessary measures.”
Kaspersky began selling antivirus and security software in the United States in 2005, and the company’s malware researchers have earned accolades from the security community for many important discoveries over the years. But in September 2017, the Department of Homeland Security (DHS) barred U.S. federal agencies from using Kaspersky software, mandating its removal within 90 days.
Cybersecurity reporter Kim Zetter notes that DHS didn’t cite any specific justification for its ban in 2017, but media reports quoting anonymous government officials referenced two incidents. Zetter wrote:
According to one story, an NSA contractor developing offensive hacking tools for the spy agency had Kaspersky software installed on his home computer where he was developing the tools, and the software detected the source code as malicious code and extracted it from his computer, as antivirus software is designed to do. A second story claimed that Israeli spies caught Russian government hackers using Kaspersky software to search customer systems for files containing U.S. secrets.
Kaspersky denied that anyone used its software to search for secret information on customer machines and said that the tools on the NSA worker’s machine were detected in the same way that all antivirus software detects files it deems suspicious and then quarantines or extracts them for analysis. Once Kaspersky discovered that the code its antivirus software detected on the NSA worker’s machine were not malicious programs but source code in development by the U.S. government for its hacking operations, CEO Eugene Kaspersky says he ordered workers to delete the code.
Last year, the U.S. Commerce Department banned the sale of Kaspersky software in the U.S. effective July 20, 2024. U.S. officials argued the ban was needed because Russian law requires domestic companies to cooperate in all official investigations, and thus the Russian government could force Kaspersky to secretly gather intelligence on its behalf.
Phishing data gathered last year by the Interisle Consulting Group ranked hosting networks by their size and concentration of spambot hosts, and found Prospero had a higher spam score than any other provider by far.
AS209030, owned by Kaspersky Lab, is providing connectivity to the bulletproof host Prospero (AS200593). Image: cidr-report.org.
It remains unclear why Kaspersky is providing transit to Prospero. Doug Madory, director of Internet analysis at Kentik, said routing records show the relationship between Prospero and Kaspersky started at the beginning of December 2024.
Madory said Kaspersky’s network appears to be hosting several financial institutions, including Russia’s largest — Alfa-Bank. Kaspersky sells services to help protect customers from distributed denial-of-service (DDoS) attacks, and Madory said it could be that Prospero is simply purchasing that protection from Kaspersky.
But if that is the case, it doesn’t make the situation any better, said Zach Edwards, a senior threat researcher at the security firm Silent Push.
“In some ways, providing DDoS protection to a well-known bulletproof hosting provider may be even worse than just allowing them to connect to the rest of the Internet over your infrastructure,” Edwards said.
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