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The Federal Bureau of Investigation (FBI) said today it worked with industry partners to seize hundreds of domains associated with NetNut, a sprawling residential proxy service operated by the publicly-traded Israeli company Alarum Technologies [NASDAQ: ALAR]. The action comes roughly two weeks after KrebsOnSecurity published findings from multiple security firms connecting NetNut to the Popa botnet, a collection of at least two million devices that have been compromised by malicious software with little or no consent from victims.

A Ukrainian man indicted in 2012 for conspiring with a prolific hacking group to steal tens of millions of dollars from U.S. businesses was arrested in Italy and is now in custody in the United States, KrebsOnSecurity has learned. Sources close to the investigation say Yuriy Igorevich Rybtsov, a 41-year-old from the Russia-controlled city of Donetsk, Ukraine, was previously referenced in U.S. federal charging documents only by his online handle "MrICQ." According to a 13-year-old indictment filed by prosecutors in Nebraska, MrICQ was a developer for a cybercrime group known as "Jabber Zeus."

On July 22, 2025, the European police agency Europol said a long-running investigation led by the French Police resulted in the arrest of a 38-year-old administrator of XSS, a Russian-language cybercrime forum with more than 50,000 members. The action has triggered an ongoing frenzy of speculation and panic among XSS denizens about the identity of the unnamed suspect, but the consensus is that he is a pivotal figure in the crime forum scene who goes by the hacker handle "Toha." Here's a deep dive on what's knowable about Toha, and a short stab at who got nabbed.

KrebsOnSecurity recently heard from a reader whose boss's email account got phished and was used to trick one of the company's customers into sending a large payment to scammers. An investigation into the attacker's infrastructure points to a long-running Nigerian cybercrime group that is actively targeting established companies in the transportation and aviation industries.

Agents with the Federal Bureau of Investigation (FBI) briefed Capitol Hill staff recently on hardening the security of their mobile devices, after a contacts list stolen from the personal phone of the White House Chief of Staff Susie Wiles was reportedly used to fuel a series of text messages and phone calls impersonating her to U.S. lawmakers. But in a letter this week to the FBI, one of the Senate's most tech-savvy lawmakers says the feds aren't doing enough to recommend more appropriate security protections that are already built into most consumer mobile devices.

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.

A Texas firm recently charged with conspiring to distribute synthetic opioids in the United States is at the center of a vast network of companies in the U.S. and Pakistan whose employees are accused of using online ads to scam westerners seeking help with trademarks, book writing, mobile app development and logo designs, a new investigation reveals.

A whistleblower at the National Labor Relations Board (NLRB) alleged last week that denizens of Elon Musk's Department of Government Efficiency (DOGE) siphoned gigabytes of data from the agency's sensitive case files in early March. The whistleblower said accounts created for DOGE at the NLRB downloaded three code repositories from GitHub. Further investigation into one of those code bundles shows it is remarkably similar to a program published in January 2025 by Marko Elez, a 25-year-old DOGE employee who has worked at a number of Musk's companies.

A Minnesota cybersecurity and computer forensics expert whose testimony has featured in thousands of courtroom trials over the past 30 years is facing questions about his credentials and an inquiry from the Federal Bureau of Investigation (FBI). Legal experts say the inquiry could be grounds to reopen a number of adjudicated cases in which the expert's testimony may have been pivotal.

Authorities in India today arrested the alleged co-founder of Garantex, a cryptocurrency exchange sanctioned by the U.S. government in 2022 for facilitating tens of billions of dollars in money laundering by transnational criminal and cybercriminal organizations. Sources close to the investigation told KrebsOnSecurity the Lithuanian national Aleksej Besciokov, 46, was apprehended while vacationing on the coast of India with his family.

A Minnesota cybersecurity and computer forensics expert whose testimony has featured in thousands of courtroom trials over the past 30 years is facing questions about his credentials and an inquiry from the Federal Bureau of Investigation (FBI). Legal experts say the inquiry could be grounds to reopen a number of adjudicated cases in which the expert's testimony may have been pivotal.

In mid-March 2024, KrebsOnSecurity revealed that the founder of the personal data removal service Onerep also founded dozens of people-search companies. Shortly after that investigation was published, Mozilla said it would stop bundling Onerep with the Firefox browser and wind down its partnership. But nearly a year later, Mozilla is still promoting it to Firefox users.

The FBI joined authorities across Europe last week in seizing domain names for Cracked and Nulled, English-language cybercrime forums with millions of users that trafficked in stolen data, hacking tools and malware. An investigation into the history of these communities shows their apparent co-founders quite openly operate an Internet service provider and a pair of e-commerce platforms catering to buyers and sellers on both forums.

A financial firm registered in Canada has emerged as the payment processor for dozens of Russian cryptocurrency exchanges and websites hawking cybercrime services aimed at Russian-speaking customers, new research finds. Meanwhile, an investigation into the Vancouver street address used by this company shows it is home to dozens of foreign currency dealers, money transfer businesses, and cryptocurrency exchanges -- none of which are physically located there.

The Federal Bureau of Investigation (FBI) is urging police departments and governments worldwide to beef up security around their email systems, citing a recent increase in cybercriminal services that use hacked police email accounts to send unauthorized subpoenas and customer data requests to U.S.-based technology companies.

In January, KrebsOnSecurity wrote about rapper Punchmade Dev, whose music videos sing the praises of a cybercrime lifestyle. That story showed how Punchmade's social media profiles promoted Punchmade-themed online stores selling bank account and payment card data. Now the Kentucky native is suing his financial institution after it blocked a $75,000 wire transfer and froze his account, citing an active law enforcement investigation.

The U.S. Department of the Treasury today unveiled sanctions against three Chinese nationals for allegedly operating 911 S5, an online anonymity service that for many years was the easiest and cheapest way to route one's Web traffic through malware-infected computers around the globe. KrebsOnSecurity identified one of the three men in a July 2022 investigation into 911 S5, which was massively hacked and then closed ten days later.

Two weeks before Russia invaded Ukraine in February 2022, a large, mysterious new Internet hosting firm called Stark Industries Solutions materialized and quickly became the epicenter of massive distributed denial-of-service (DDoS) attacks on government and commercial targets in Ukraine and Europe. An investigation into Stark Industries reveals it is being used as a global proxy network that conceals the true source of cyberattacks and disinformation campaigns against enemies of Russia.

The data privacy company Onerep.com bills itself as a Virginia-based service for helping people remove their personal information from almost 200 people-search websites. However, an investigation into the history of onerep.com finds this company is operating out of Belarus and Cyprus, and that its founder has launched dozens of people-search services over the years.

On Jan. 9, 2024, U.S. authorities arrested a 19-year-old Florida man charged with wire fraud, aggravated identity theft, and conspiring with others to use SIM-swapping to steal cryptocurrency. Sources close to the investigation tell KrebsOnSecurity the accused was a key member of a criminal hacking group blamed for a string of cyber intrusions at major U.S. technology companies during the summer of 2022.