Krebs on Security

Oregon Man Charged in ‘Rapper Bot’ DDoS Service

A 22-year-old Oregon man has been arrested on suspicion of operating “Rapper Bot,” a massive botnet used to power a service for launching distributed denial-of-service (DDoS) attacks against targets — including a March 2025 DDoS that knocked Twitter/X offline. The Justice Department asserts the suspect and an unidentified co-conspirator rented out the botnet to online extortionists, and tried to stay off the radar of law enforcement by ensuring that their botnet was never pointed at KrebsOnSecurity.

On August 6, 2025, federal agents arrested Ethan J. Foltz of Springfield, Ore. on suspicion of operating Rapper Bot, a globally dispersed collection of tens of thousands of hacked Internet of Things (IoT) devices.

The complaint against Foltz explains the attacks usually clocked in at more than two terabits of junk data per second (a terabit is one trillion bits of data), which is more than enough traffic to cause serious problems for all but the most well-defended targets. The government says Rapper Bot consistently launched attacks that were “hundreds of times larger than the expected capacity of a typical server located in a data center,” and that some of its biggest attacks exceeded six terabits per second.

Indeed, Rapper Bot was reportedly responsible for the March 10, 2025 attack that caused intermittent outages on Twitter/X. The government says Rapper Bot’s most lucrative and frequent customers were involved in extorting online businesses — including numerous gambling operations based in China.

The criminal complaint was written by Elliott Peterson, an investigator with the Defense Criminal Investigative Service (DCIS), the criminal investigative division of the Department of Defense (DoD) Office of Inspector General. The complaint notes the DCIS got involved because several Internet addresses maintained by the DoD were the target of Rapper Bot attacks.

Peterson said he tracked Rapper Bot to Foltz after a subpoena to an ISP in Arizona that was hosting one of the botnet’s control servers showed the account was paid for via PayPal. More legal process to PayPal revealed Foltz’s Gmail account and previously used IP addresses. A subpoena to Google showed the defendant searched security blogs constantly for news about Rapper Bot, and for updates about competing DDoS-for-hire botnets.

According to the complaint, after having a search warrant served on his residence the defendant admitted to building and operating Rapper Bot, sharing the profits 50/50 with a person he claimed to know only by the hacker handle “Slaykings.” Foltz also shared with investigators the logs from his Telegram chats, wherein Foltz and Slaykings discussed how best to stay off the radar of law enforcement investigators while their competitors were getting busted.

Specifically, the two hackers chatted about a May 20 attack against KrebsOnSecurity.com that clocked in at more than 6.3 terabits of data per second. The brief attack was notable because at the time it was the largest DDoS that Google had ever mitigated (KrebsOnSecurity sits behind the protection of Project Shield, a free DDoS defense service that Google provides to websites offering news, human rights, and election-related content).

The May 2025 DDoS was launched by an IoT botnet called Aisuru, which I discovered was operated by a 21-year-old man in Brazil named Kaike Southier Leite. This individual was more commonly known online as “Forky,” and Forky told me he wasn’t afraid of me or U.S. federal investigators. Nevertheless, the complaint against Foltz notes that Forky’s botnet seemed to diminish in size and firepower at the same time that Rapper Bot’s infection numbers were on the upswing.

“Both FOLTZ and Slaykings were very dismissive of attention seeking activities, the most extreme of which, in their view, was to launch DDoS attacks against the website of the prominent cyber security journalist Brian Krebs,” Peterson wrote in the criminal complaint.

“You see, they’ll get themselves [expletive],” Slaykings wrote in response to Foltz’s comments about Forky and Aisuru bringing too much heat on themselves.

“Prob cuz [redacted] hit krebs,” Foltz wrote in reply.

“Going against Krebs isn’t a good move,” Slaykings concurred. “It isn’t about being a [expletive] or afraid, you just get a lot of problems for zero money. Childish, but good. Let them die.”

“Ye, it’s good tho, they will die,” Foltz replied.

The government states that just prior to Foltz’s arrest, Rapper Bot had enslaved an estimated 65,000 devices globally. That may sound like a lot, but the complaint notes the defendants weren’t interested in making headlines for building the world’s largest or most powerful botnet.

Quite the contrary: The complaint asserts that the accused took care to maintain their botnet in a “Goldilocks” size — ensuring that “the number of devices afforded powerful attacks while still being manageable to control and, in the hopes of Foltz and his partners, small enough to not be detected.”

The complaint states that several days later, Foltz and Slaykings returned to discussing what that they expected to befall their rival group, with Slaykings stating, “Krebs is very revenge. He won’t stop until they are [expletive] to the bone.”

“Surprised they have any bots left,” Foltz answered.

“Krebs is not the one you want to have on your back. Not because he is scary or something, just because he will not give up UNTIL you are [expletive] [expletive]. Proved it with Mirai and many other cases.”

[Unknown expletives aside, that may well be the highest compliment I’ve ever been paid by a cybercriminal. I might even have part of that quote made into a t-shirt or mug or something. It’s also nice that they didn’t let any of their customers attack my site — if even only out of a paranoid sense of self-preservation.]

Foltz admitted to wiping the user and attack logs for the botnet approximately once a week, so investigators were unable to tally the total number of attacks, customers and targets of this vast crime machine. But the data that was still available showed that from April 2025 to early August, Rapper Bot conducted over 370,000 attacks, targeting 18,000 unique victims across 1,000 networks, with the bulk of victims residing in China, Japan, the United States, Ireland and Hong Kong (in that order).

According to the government, Rapper Bot borrows much of its code from fBot, a DDoS malware strain also known as Satori. In 2020, authorities in Northern Ireland charged a then 20-year-old man named Aaron “Vamp” Sterritt with operating fBot with a co-conspirator. U.S. prosecutors are still seeking Sterritt’s extradition to the United States. fBot is itself a variation of the Mirai IoT botnet that has ravaged the Internet with DDoS attacks since its source code was leaked back in 2016.

The complaint says Foltz and his partner did not allow most customers to launch attacks that were more than 60 seconds in duration — another way they tried to keep public attention to the botnet at a minimum. However, the government says the proprietors also had special arrangements with certain high-paying clients that allowed much larger and longer attacks.

Most people who have never been on the receiving end of a monster DDoS attack have no idea of the cost and disruption that such sieges can bring. The DCIS’s Peterson wrote that he was able to test the botnet’s capabilities while interviewing Foltz, and that found that “if this had been a server upon which I was running a website, using services such as load balancers, and paying for both outgoing and incoming data, at estimated industry average rates the attack (2+ Terabits per second times 30 seconds) might have cost the victim anywhere from $500 to $10,000.”

“DDoS attacks at this scale often expose victims to devastating financial impact, and a potential alternative, network engineering solutions that mitigate the expected attacks such as overprovisioning, i.e. increasing potential Internet capacity, or DDoS defense technologies, can themselves be prohibitively expensive,” the complaint continues. “This ‘rock and a hard place’ reality for many victims can leave them acutely exposed to extortion demands – ‘pay X dollars and the DDoS attacks stop’.”

The Telegram chat records show that the day before Peterson and other federal agents raided Foltz’s residence, Foltz allegedly told his partner he’d found 32,000 new devices that were vulnerable to a previously unknown exploit.

Shortly before the search warrant was served on his residence, Foltz allegedly told his partner that “Once again we have the biggest botnet in the community.” The following day, Foltz told his partner that it was going to be a great day — the biggest so far in terms of income generated by Rapper Bot.

“I sat next to Foltz while the messages poured in — promises of $800, then $1,000, the proceeds ticking up as the day went on,” Peterson wrote. “Noticing a change in Foltz’ behavior and concerned that Foltz was making changes to the botnet configuration in real time, Slaykings asked him ‘What’s up?’ Foltz deftly typed out some quick responses. Reassured by Foltz’ answer, Slaykings responded, ‘Ok, I’m the paranoid one.”

The case is being prosecuted by Assistant U.S. Attorney Adam Alexander in the District of Alaska (at least some of the devices found to be infected with Rapper Bot were located there, and it is where Peterson is stationed). Foltz faces one count of aiding and abetting computer intrusions. If convicted, he faces a maximum penalty of 10 years in prison, although a federal judge is unlikely to award anywhere near that kind of sentence for a first-time conviction.

Krebs on Security

Oops: DanaBot Malware Devs Infected Their Own PCs

The U.S. government today unsealed criminal charges against 16 individuals accused of operating and selling DanaBot, a prolific strain of information-stealing malware that has been sold on Russian cybercrime forums since 2018. The FBI says a newer version of DanaBot was used for espionage, and that many of the defendants exposed their real-life identities after accidentally infecting their own systems with the malware.

Initially spotted in May 2018 by researchers at the email security firm Proofpoint, DanaBot is a malware-as-a-service platform that specializes in credential theft and banking fraud.

Today, the U.S. Department of Justice unsealed a criminal complaint and indictment from 2022, which said the FBI identified at least 40 affiliates who were paying between $3,000 and $4,000 a month for access to the information stealer platform.

The government says the malware infected more than 300,000 systems globally, causing estimated losses of more than $50 million. The ringleaders of the DanaBot conspiracy are named as Aleksandr Stepanov, 39, a.k.a. “JimmBee,” and Artem Aleksandrovich Kalinkin, 34, a.k.a. “Onix”, both of Novosibirsk, Russia. Kalinkin is an IT engineer for the Russian state-owned energy giant Gazprom. His Facebook profile name is “Maffiozi.”

According to the FBI, there were at least two major versions of DanaBot; the first was sold between 2018 and June 2020, when the malware stopped being offered on Russian cybercrime forums. The government alleges that the second version of DanaBot — emerging in January 2021 — was provided to co-conspirators for use in targeting military, diplomatic and non-governmental organization computers in several countries, including the United States, Belarus, the United Kingdom, Germany, and Russia.

“Unindicted co-conspirators would use the Espionage Variant to compromise computers around the world and steal sensitive diplomatic communications, credentials, and other data from these targeted victims,” reads a grand jury indictment dated Sept. 20, 2022. “This stolen data included financial transactions by diplomatic staff, correspondence concerning day-to-day diplomatic activity, as well as summaries of a particular country’s interactions with the United States.”

The indictment says the FBI in 2022 seized servers used by the DanaBot authors to control their malware, as well as the servers that stored stolen victim data. The government said the server data also show numerous instances in which the DanaBot defendants infected their own PCs, resulting in their credential data being uploaded to stolen data repositories that were seized by the feds.

“In some cases, such self-infections appeared to be deliberately done in order to test, analyze, or improve the malware,” the criminal complaint reads. “In other cases, the infections seemed to be inadvertent – one of the hazards of committing cybercrime is that criminals will sometimes infect themselves with their own malware by mistake.”

A statement from the DOJ says that as part of today’s operation, agents with the Defense Criminal Investigative Service (DCIS) seized the DanaBot control servers, including dozens of virtual servers hosted in the United States. The government says it is now working with industry partners to notify DanaBot victims and help remediate infections. The statement credits a number of security firms with providing assistance to the government, including ESET, Flashpoint, Google, Intel 471, Lumen, PayPal, Proofpoint, Team CYMRU, and ZScaler.

It’s not unheard of for financially-oriented malicious software to be repurposed for espionage. A variant of the ZeuS Trojan, which was used in countless online banking attacks against companies in the United States and Europe between 2007 and at least 2015, was for a time diverted to espionage tasks by its author.

As detailed in this 2015 story, the author of the ZeuS trojan created a custom version of the malware to serve purely as a spying machine, which scoured infected systems in Ukraine for specific keywords in emails and documents that would likely only be found in classified documents.

The public charging of the 16 DanaBot defendants comes a day after Microsoft joined a slew of tech companies in disrupting the IT infrastructure for another malware-as-a-service offering — Lumma Stealer, which is likewise offered to affiliates under tiered subscription prices ranging from $250 to $1,000 per month. Separately, Microsoft filed a civil lawsuit to seize control over 2,300 domain names used by Lumma Stealer and its affiliates.

Further reading:

Danabot: Analyzing a Fallen Empire

ZScaler blog: DanaBot Launches DDoS Attack Against the Ukrainian Ministry of Defense

Flashpoint: Operation Endgame DanaBot Malware

Team CYMRU: Inside DanaBot’s Infrastructure: In Support of Operation Endgame II

March 2022 criminal complaint v. Artem Aleksandrovich Kalinkin

September 2022 grand jury indictment naming the 16 defendants