Twitter’s Clumsy Pivot to X.com Is a Gift to Phishers

On April 9, Twitter/X began automatically modifying links that mention “twitter.com” to read “x.com” instead. But over the past 48 hours, dozens of new domain names have been registered that demonstrate how this change could be used to craft convincing phishing links — such as fedetwitter[.]com, which until very recently rendered as fedex.com in tweets.

A search at DomainTools.com shows at least 60 domain names have been registered over the past two days for domains ending in “twitter.com,” although research so far shows the majority of these domains have been registered “defensively” by private individuals to prevent the domains from being purchased by scammers.

Those include carfatwitter.com, which Twitter/X truncated to carfax.com when the domain appeared in user messages or tweets. Visiting this domain currently displays a message that begins, “Are you serious, X Corp?”

Update: It appears Twitter/X has corrected its mistake, and no longer truncates any domain ending in “twitter.com” to “x.com.”

Original story:

The same message is on other newly registered domains, including goodrtwitter.com (goodrx.com), neobutwitter.com (neobux.com), roblotwitter.com (roblox.com), square-enitwitter.com (square-enix.com) and yandetwitter.com (yandex.com). The message left on these domains indicates they were defensively registered by a user on Mastodon whose bio says they are a systems admin/engineer. That profile has not responded to requests for comment.

A number of these new domains including “twitter.com” appear to be registered defensively by Twitter/X users in Japan. The domain netflitwitter.com (netflix.com, to Twitter/X users) now displays a message saying it was “acquired to prevent its use for malicious purposes,” along with a Twitter/X username.

The domain mentioned at the beginning of this story — fedetwitter.com — redirects users to the blog of a Japanese technology enthusiast. A user with the handle “amplest0e” appears to have registered space-twitter.com, which Twitter/X users would see as the CEO’s “space-x.com.” The domain “ametwitter.com” already redirects to the real americanexpress.com.

Some of the domains registered recently and ending in “twitter.com” currently do not resolve and contain no useful contact information in their registration records. Those include firefotwitter[.]com (firefox.com), ngintwitter[.]com (nginx.com), and webetwitter[.]com (webex.com).

Sean McNee, vice president of research and data at DomainTools, told KrebsOnSecurity it appears Twitter/X did not properly limit its redirection efforts.

“Bad actors could register domains as a way to divert traffic from legitimate sites or brands given the opportunity — many such brands in the top million domains end in x, such as webex, hbomax, xerox, xbox, and more,” McNee said. “It is also notable that several other globally popular brands, such as Rolex and Linux, were also on the list of registered domains.”

The apparent oversight by Twitter/X was cause for amusement and amazement from many former users who have migrated to other social media platforms since the new CEO took over. Matthew Garrett, a lecturer at U.C. Berkeley’s School of Information, summed up the Schadenfreude thusly:

“Twitter just doing a ‘redirect links in tweets that go to x.com to twitter.com instead but accidentally do so for all domains that end x.com like eg spacex.com going to spacetwitter.com’ is not absolutely the funniest thing I could imagine but it’s high up there.”

Feds Take Down 13 More DDoS-for-Hire Services

The U.S. Federal Bureau of Investigation (FBI) this week seized 13 domain names connected to “booter” services that let paying customers launch crippling distributed denial-of-service (DDoS) attacks. Ten of the domains are reincarnations of DDoS-for-hire services the FBI seized in December 2022, when it charged six U.S. men with computer crimes for allegedly operating booters.

Booter services are advertised through a variety of methods, including Dark Web forums, chat platforms and even youtube.com. They accept payment via PayPal, Google Wallet, and/or cryptocurrencies, and subscriptions can range in price from just a few dollars to several hundred per month. The services are generally priced according to the volume of traffic to be hurled at the target, the duration of each attack, and the number of concurrent attacks allowed.

The websites that saw their homepages replaced with seizure notices from the FBI this week include booter services like cyberstress[.]org and exoticbooter[.]com, which the feds say were used to launch millions of attacks against millions of victims.

“School districts, universities, financial institutions and government websites are among the victims who have been targeted in attacks launched by booter services,” federal prosecutors in Los Angeles said in a statement.

Purveyors of booters or “stressers” claim they are not responsible for how customers use their services, and that they aren’t breaking the law because — like most security tools — these services can be used for good or bad purposes. Most booter sites employ wordy “terms of use” agreements that require customers to agree they will only stress-test their own networks — and that they won’t use the service to attack others.

But the DOJ says these disclaimers usually ignore the fact that most booter services are heavily reliant on constantly scanning the Internet to commandeer misconfigured devices that are critical for maximizing the size and impact of DDoS attacks. What’s more, none of the services seized by the government required users to demonstrate that they own the Internet addresses being stress-tested, something a legitimate testing service would insist upon.

This is the third in a series of U.S. and international law enforcement actions targeting booter services. In December 2022, the feds seized four-dozen booter domains and charged six U.S. men with computer crimes related to their alleged ownership of the popular DDoS-for-hire services. In December 2018, the feds targeted 15 booter sites, and three booter store defendants who later pleaded guilty.

While the FBI’s repeated seizing of booter domains may seem like an endless game of virtual Whac-a-Mole, continuously taking these services offline imposes high enough costs for the operators that some of them will quit the business altogether, says Richard Clayton, director of Cambridge University’s Cybercrime Centre.

In 2020, Clayton and others published “Cybercrime is Mostly Boring,” an academic study on the quality and types of work needed to build, maintain and defend illicit enterprises that make up a large portion of the cybercrime-as-a-service market. The study found that operating a booter service effectively requires a mind-numbing amount of constant, tedious work that tends to produce high burnout rates for booter service operators — even when the service is operating efficiently and profitably.

For example, running an effective booter service requires a substantial amount of administrative work and maintenance, much of which involves constantly scanning for, commandeering and managing large collections of remote systems that can be used to amplify online attacks, Clayton said. On top of that, building brand recognition and customer loyalty takes time.

“If you’re running a booter and someone keeps taking your domain or hosting away, you have to then go through doing the same boring work all over again,” Clayton told KrebsOnSecurity. “One of the guys the FBI arrested in December [2022] spent six months moaning that he lost his servers, and could people please lend him some money to get it started again.”

In a statement released Wednesday, prosecutors in Los Angeles said four of the six men charged last year for running booter services have since pleaded guilty. However, at least one of the defendants from the 2022 booter bust-up — John M. Dobbs, 32, of Honolulu, HI — has pleaded not guilty and is signaling he intends to take his case to trial.

Dobbs is a computer science graduate student who for the past decade openly ran IPStresser[.]com, a popular and powerful attack-for-hire service that he registered with the state of Hawaii using his real name and address. Likewise, the domain was registered in Dobbs’s name and hometown in Pennsylvania. Prosecutors say Dobbs’ service attracted more than two million registered users, and was responsible for launching a staggering 30 million distinct DDoS attacks.

Many accused stresser site operators have pleaded guilty over the years after being hit with federal criminal charges. But the government’s core claim — that operating a booter site is a violation of U.S. computer crime laws — wasn’t properly tested in the courts until September 2021.

That was when a jury handed down a guilty verdict against Matthew Gatrel, a then 32-year-old St. Charles, Ill. man charged in the government’s first 2018 mass booter bust-up. Despite admitting to FBI agents that he ran two booter services (and turning over plenty of incriminating evidence in the process), Gatrel opted to take his case to trial, defended the entire time by court-appointed attorneys.

Gatrel was convicted on all three charges of violating the Computer Fraud and Abuse Act, including conspiracy to commit unauthorized impairment of a protected computer, conspiracy to commit wire fraud, and unauthorized impairment of a protected computer. He was sentenced to two years in prison.

A copy of the FBI’s booter seizure warrant is here (PDF). According to the DOJ, the defendants who pleaded guilty to operating booter sites include:

–Jeremiah Sam Evans Miller, aka “John The Dev,” 23, of San Antonio, Texas, who pleaded guilty on April 6 to conspiracy and violating the computer fraud and abuse act related to the operation of a booter service named RoyalStresser[.]com (formerly known as Supremesecurityteam[.]com);

–Angel Manuel Colon Jr., aka “Anonghost720” and “Anonghost1337,” 37, of Belleview, Florida, who pleaded guilty on February 13 to conspiracy and violating the computer fraud and abuse act related to the operation of a booter service named SecurityTeam[.]io;

–Shamar Shattock, 19, of Margate, Florida, who pleaded guilty on March 22 to conspiracy to violate the computer fraud and abuse act related to the operation of a booter service known as Astrostress[.]com;

–Cory Anthony Palmer, 23, of Lauderhill, Florida, who pleaded guilty on February 16 to conspiracy to violate the computer fraud and abuse act related to the operation of a booter service known as Booter[.]sx.

All four defendants are scheduled to be sentenced this summer.

The booter domains seized by the FBI this week include:

cyberstress[.]org
exoticbooter[.]com
layerstress[.]net
orbitalstress[.]xyz
redstresser[.]io
silentstress[.]wtf
sunstresser[.]net
silent[.]to
mythicalstress[.]net
dreams-stresser[.]org
stresserbest[.]io
stresserus[.]io
quantum-stress[.]org

Many Public Salesforce Sites are Leaking Private Data

A shocking number of organizations — including banks and healthcare providers — are leaking private and sensitive information from their public Salesforce Community websites, KrebsOnSecurity has learned. The data exposures all stem from a misconfiguration in Salesforce Community that allows an unauthenticated user to access records that should only be available after logging in.

Salesforce Community is a widely-used cloud-based software product that makes it easy for organizations to quickly create websites. Customers can access a Salesforce Community website in two ways: Authenticated access (requiring login), and guest user access (no login required). The guest access feature allows unauthenticated users to view specific content and resources without needing to log in.

However, sometimes Salesforce administrators mistakenly grant guest users access to internal resources, which can cause unauthorized users to access an organization’s private information and lead to potential data leaks.

Until being contacted by this reporter on Monday, the state of Vermont had at least five separate Salesforce Community sites that allowed guest access to sensitive data, including a Pandemic Unemployment Assistance program that exposed the applicant’s full name, Social Security number, address, phone number, email, and bank account number.

Vermont’s Chief Information Security Officer Scott Carbee said his security teams have been conducting a full review of their Salesforce Community sites, and already found one additional Salesforce site operated by the state that was also misconfigured to allow guest access to sensitive information.

“My team is frustrated by the permissive nature of the platform,” Carbee said.

Carbee said the vulnerable sites were all created rapidly in response to the Coronavirus pandemic, and were not subjected to their normal security review process.

“During the pandemic, we were largely standing up tons of applications, and let’s just say a lot of them didn’t have the full benefit of our dev/ops process,” Carbee said. “In our case, we didn’t have any native Salesforce developers when we had to suddenly stand up all these sites.”

Earlier this week, KrebsOnSecurity notified Columbus, Ohio-based Huntington Bank that its recently acquired TCF Bank had a Salesforce Community website that was leaking documents related to commercial loans. The data fields in those loan applications included name, address, full Social Security number, title, federal ID, IP address, average monthly payroll, and loan amount.

Huntington Bank has disabled the leaky TCF Bank Salesforce website. Matthew Jennings, deputy chief information security officer at Huntington, said the company was still investigating how the misconfiguration occurred, how long it lasted, and how many records may have been exposed.

KrebsOnSecurity learned of the leaks from security researcher Charan Akiri, who said he wrote a program that identified hundreds of other organizations running misconfigured Salesforce pages. But Akiri said he’s been wary of probing too far, and has had difficulty getting responses from most of the organizations he has notified to date.

“In January and February 2023, I contacted government organizations and several companies, but I did not receive any response from these organizations,” Akiri said. “To address the issue further, I reached out to several CISOs on LinkedIn and Twitter. As a result, five companies eventually fixed the problem. Unfortunately, I did not receive any responses from government organizations.”

The problem Akiri has been trying to raise awareness about came to the fore in August 2021, when security researcher Aaron Costello published a blog post explaining how misconfigurations in Salesforce Community sites could be exploited to reveal sensitive data (Costello subsequently published a follow-up post detailing how to lock down Salesforce Community sites).

On Monday, KrebsOnSecurity used Akiri’s findings to notify Washington D.C. city administrators that at least five different public DC Health websites were leaking sensitive information. One DC Health Salesforce Community website designed for health professionals seeking to renew licenses with the city leaked documents that included the applicant’s full name, address, Social Security number, date of birth, license number and expiration, and more.

Akiri said he notified the Washington D.C. government in February about his findings, but received no response. Reached by KrebsOnSecurity, interim Chief Information Security Officer Mike Rupert initially said the District had hired a third party to investigate, and that the third party confirmed the District’s IT systems were not vulnerable to data loss from the reported Salesforce configuration issue.

But after being presented with a document including the Social Security number of a health professional in D.C. that was downloaded in real-time from the DC Health public Salesforce website, Rupert acknowledged his team had overlooked some configuration settings.

Washington, D.C. health administrators are still smarting from a data breach earlier this year at the health insurance exchange DC Health Link, which exposed personal information for more than 56,000 users, including many members of Congress.

That data later wound up for sale on a top cybercrime forum. The Associated Press reports that the DC Health Link breach was likewise the result of human error, and said an investigation revealed the cause was a DC Health Link server that was “misconfigured to allow access to the reports on the server without proper authentication.”

Salesforce says the data exposures are not the result of a vulnerability inherent to the Salesforce platform, but they can occur when customers’ access control permissions are misconfigured.

“As previously communicated to all Experience Site and Sites customers, we recommend utilizing the Guest User Access Report Package to assist in reviewing access control permissions for unauthenticated users,” reads a Salesforce advisory from Sept. 2022. “Additionally, we suggest reviewing the following Help article, Best Practices and Considerations When Configuring the Guest User Profile.”

In a written statement, Salesforce said it is actively focused on data security for organizations with guest users, and that it continues to release “robust tools and guidance for our customers,” including:

Guest User Access Report 

Control Which Users Experience Cloud Site Users Can See

Best Practices and Considerations When Configuring the Guest User Profile

“We’ve also continued to update our Guest User security policies, beginning with our Spring ‘21 release with more to come in Summer ‘23,” the statement reads. “Lastly, we continue to proactively communicate with customers to help them understand the capabilities available to them, and how they can best secure their instance of Salesforce to meet their security, contractual, and regulatory obligations.”

Thinking of Hiring or Running a Booter Service? Think Again.

Most people who operate DDoS-for-hire businesses attempt to hide their true identities and location. Proprietors of these so-called “booter” or “stresser” services — designed to knock websites and users offline — have long operated in a legally murky area of cybercrime law. But until recently, their biggest concern wasn’t avoiding capture or shutdown by the feds: It was minimizing harassment from unhappy customers or victims, and insulating themselves against incessant attacks from competing DDoS-for-hire services.

And then there are booter store operators like John Dobbs, a 32-year-old computer science graduate student living in Honolulu, Hawaii. For at least a decade until late last year, Dobbs openly operated IPStresser[.]com, a popular and powerful attack-for-hire service that he registered with the state of Hawaii using his real name and address. Likewise, the domain was registered in Dobbs’s name and hometown in Pennsylvania.

The only work experience Dobbs listed on his resume was as a freelance developer from 2013 to the present day. Dobbs’s resume doesn’t name his booter service, but in it he brags about maintaining websites with half a million page views daily, and “designing server deployments for performance, high-availability and security.”

In December 2022, the U.S. Department of Justice seized Dobbs’s IPStresser website and charged him with one count of aiding and abetting computer intrusions. Prosecutors say his service attracted more than two million registered users, and was responsible for launching a staggering 30 million distinct DDoS attacks.

The government seized four-dozen booter domains, and criminally charged Dobbs and five other U.S. men for allegedly operating stresser services. This was the Justice Department’s second such mass takedown targeting DDoS-for-hire services and their accused operators. In 2018, the feds seized 15 stresser sites, and levied cybercrime charges against three men for their operation of booter services.

Many accused stresser site operators have pleaded guilty over the years after being hit with federal criminal charges. But the government’s core claim — that operating a booter site is a violation of U.S. computer crime laws — wasn’t properly tested in the courts until September 2021.

That was when a jury handed down a guilty verdict against Matthew Gatrel, a then 32-year-old St. Charles, Ill. man charged in the government’s first 2018 mass booter bust-up. Despite admitting to FBI agents that he ran two booter services (and turning over plenty of incriminating evidence in the process), Gatrel opted to take his case to trial, defended the entire time by court-appointed attorneys.

Prosecutors said Gatrel’s booter services — downthem[.]org and ampnode[.]com — helped some 2,000 paying customers launch debilitating digital assaults on more than 20,000 targets, including many government, banking, university and gaming websites.

Gatrel was convicted on all three charges of violating the Computer Fraud and Abuse Act, including conspiracy to commit unauthorized impairment of a protected computer, conspiracy to commit wire fraud, and unauthorized impairment of a protected computer. He was sentenced to two years in prison.

Now, it appears Dobbs is also planning to take his chances with a jury. On Jan. 4, Dobbs entered a plea of not guilty. Neither Dobbs nor his court-appointed attorney responded to requests for comment.

But as it happens, Dobbs himself provided some perspective on his thinking in an email exchange with KrebsOnSecurity back in 2020. I’d reached out to Dobbs because it was obvious he didn’t mind if people knew he operated one of the world’s most popular DDoS-for-hire sites, and I was genuinely curious why he was so unafraid of getting raided by the feds.

“Yes, I am the owner of the domain you listed, however you are not authorized to post an article containing said domain name, my name or this email address without my prior written permission,” Dobbs replied to my initial outreach on March 10, 2020 using his email address from the University of Hawaii at Manoa.

A few hours later, I received more strident instructions from Dobbs, this time via his official email address at ipstresser[.]com.

“I will state again for absolute clarity, you are not authorized to post an article containing ipstresser.com, my name, my GitHub profile and/or my hawaii.edu email address,” Dobbs wrote, as if taking dictation from a lawyer who doesn’t understand how the media works.

When pressed for particulars on his business, Dobbs replied that the number of IPStresser customers was “privileged information,” and said he didn’t even advertise the service. When asked whether he was concerned that many of his competitors were by then serving jail time for operating similar booter services, Dobbs maintained that the way he’d set up the business insulated him from any liability.

“I have been aware of the recent law enforcement actions against other operators of stress testing services,” Dobbs explained. “I cannot speak to the actions of these other services, but we take proactive measures to prevent misuse of our service and we work with law enforcement agencies regarding any reported abuse of our service.”

What were those proactive measures? In a 2015 interview with ZDNet France, Dobbs asserted that he was immune from liability because his clients all had to submit a digital signature attesting that they wouldn’t use the site for illegal purposes.

“Our terms of use are a legal document that protects us, among other things, from certain legal consequences,” Dobbs told ZDNet. “Most other sites are satisfied with a simple checkbox, but we ask for a digital signature in order to imply real consent from our customers.”

Dobbs told KrebsOnSecurity his service didn’t generate much of a profit, but rather that he was motivated by “filling a legitimate need.”

“My reason for offering the service is to provide the ability to test network security measures before someone with malicious intent attacks said network and causes downtime,” he said. “Sure, some people see only the negatives, but there is a long list of companies I have worked with over the years who would say my service is a godsend and has helped them prevent tens of thousands of dollars in downtime resulting from a malicious attack.”

“I do not believe that providing such a service is illegal, assuming proper due diligence to prevent malicious use of the service, as is the case for IPstresser[.]com,” Dobbs continued. “Someone using such a service to conduct unauthorized testing is illegal in many countries, however, the legal liability is that of the user, not of the service provider.”

Dobbs’s profile on GitHub includes more of his ideas about his work, including a curious piece on “software engineering ethics.” In his January 2020 treatise “My Software Engineering Journey,” Dobbs laments that nothing in his formal education prepared him for the reality that a great deal of his work would be so tedious and repetitive (this tracks closely with a 2020 piece here called Career Choice Tip: Cybercrime is Mostly Boring).

“One area of software engineering that I think should be covered more in university classes is maintenance,” Dobbs wrote. “Projects are often worked on for at most a few months, and students do not experience the maintenance aspect of software engineering until they reach the workplace. Let’s face it, ongoing maintenance of a project is boring; there is nothing like the euphoria of completing a project you have been working on for months and releasing it to the world, but I would say that half of my professional career has been related to maintenance.”

Allison Nixon is chief research officer at the New York-based cybersecurity firm Unit 221B. Nixon is part of a small group of researchers who have been closely tracking the DDoS-for-hire industry for years, and she said Dobbs’s claim that what he’s doing is legal makes sense given that it took years for the government to recognize the size of the problem.

“These guys are arguing that their services are legal because for a long time nothing happened to them,” Nixon said. “It’s difficult to argue something is illegal if no one has ever been arrested for it before.”

Nixon says the government’s fight against the booter services — and by extension other types of cybercrimes — is hampered by a legal system that often takes years to cycle through cybercrime cases.

“With cybercrime, the cycle between the crime and investigation and arrest can often take a year or more, and that’s for a really fast case,” Nixon said. “If someone robbed a store, we’d expect a police response within a few minutes. If someone robs a bank’s website, there might be some indication of police activity within a year.”

Nixon praised the 2022 and 2018 booter takedown operations as “huge steps forward,” but added that “there need to be more of them, and faster.”

“This time lag is part of the reason it’s so difficult to shut down the pipeline of new talent going into cybercrime,” she said. “They think what they’re doing is legal because nothing has happened, and because of the amount of time it takes to shut these things down. And it’s really a big problem, where we see a lot of people becoming criminals on the basis that what they’re doing isn’t really illegal because the cops won’t do anything.”

In December 2020, Dobbs filed an application with the state of Hawaii to withdraw IP Stresser Inc. from its roster of active companies. But according to prosecutors, Dobbs would continue to operate his DDoS-for-hire site until at least November 2022.

Two months after our 2020 email interview, Dobbs would earn his second bachelor’s degree (in computer science; his resume says he earned a bachelor’s in civil engineering from Drexel University in 2013). The federal charges against Dobbs came just as he was preparing to enter his final semester toward a master’s degree in computer science at the University of Hawaii.

Nixon says she has a message for anyone involved in operating a DDoS-for-hire service.

“Unless you are verifying that the target owns the infrastructure you’re targeting, there is no legal way to operate a DDoS-for-hire service,” she said. “There is no Terms of Service you could put on the site that would somehow make it legal.”

And her message to the customers of those booter services? It’s a compelling one to ponder, particularly now that investigators in the United States, U.K. and elsewhere have started going after booter service customers.

“When a booter service claims they don’t share logs, they’re lying because logs are legal leverage for when the booter service operator gets arrested,” Nixon said. “And when they do, you’re going to be the first people they throw under the bus.”

How 1-Time Passcodes Became a Corporate Liability

Phishers are enjoying remarkable success using text messages to steal remote access credentials and one-time passcodes from employees at some of the world’s largest technology companies and customer support firms. A recent spate of SMS phishing attacks from one cybercriminal group has spawned a flurry of breach disclosures from affected companies, which are all struggling to combat the same lingering security threat: The ability of scammers to interact directly with employees through their mobile devices.

In mid-June 2022, a flood of SMS phishing messages began targeting employees at commercial staffing firms that provide customer support and outsourcing to thousands of companies. The missives asked users to click a link and log in at a phishing page that mimicked their employer’s Okta authentication page. Those who submitted credentials were then prompted to provide the one-time password needed for multi-factor authentication.

The phishers behind this scheme used newly-registered domains that often included the name of the target company, and sent text messages urging employees to click on links to these domains to view information about a pending change in their work schedule.

The phishing sites leveraged a Telegram instant message bot to forward any submitted credentials in real-time, allowing the attackers to use the phished username, password and one-time code to log in as that employee at the real employer website. But because of the way the bot was configured, it was possible for security researchers to capture the information being sent by victims to the public Telegram server.

This data trove was first reported by security researchers at Singapore-based Group-IB, which dubbed the campaign “0ktapus” for the attackers targeting organizations using identity management tools from Okta.com.

“This case is of interest because despite using low-skill methods it was able to compromise a large number of well-known organizations,” Group-IB wrote. “Furthermore, once the attackers compromised an organization they were quickly able to pivot and launch subsequent supply chain attacks, indicating that the attack was planned carefully in advance.”

It’s not clear how many of these phishing text messages were sent out, but the Telegram bot data reviewed by KrebsOnSecurity shows they generated nearly 10,000 replies over approximately two months of sporadic SMS phishing attacks targeting more than a hundred companies.

A great many responses came from those who were apparently wise to the scheme, as evidenced by the hundreds of hostile replies that included profanity or insults aimed at the phishers: The very first reply recorded in the Telegram bot data came from one such employee, who responded with the username “havefuninjail.”

Still, thousands replied with what appear to be legitimate credentials — many of them including one-time codes needed for multi-factor authentication. On July 20, the attackers turned their sights on internet infrastructure giant Cloudflare.com, and the intercepted credentials show at least three employees fell for the scam.

In a blog post earlier this month, Cloudflare said it detected the account takeovers and that no Cloudflare systems were compromised. Cloudflare said it does not rely on one-time passcodes as a second factor, so there was nothing to provide to the attackers. But Cloudflare said it wanted to call attention to the phishing attacks because they would probably work against most other companies.

“This was a sophisticated attack targeting employees and systems in such a way that we believe most organizations would be likely to be breached,” Cloudflare CEO Matthew Prince wrote. “On July 20, 2022, the Cloudflare Security team received reports of employees receiving legitimate-looking text messages pointing to what appeared to be a Cloudflare Okta login page. The messages began at 2022-07-20 22:50 UTC. Over the course of less than 1 minute, at least 76 employees received text messages on their personal and work phones. Some messages were also sent to the employees family members.”

On three separate occasions, the phishers targeted employees at Twilio.com, a San Francisco based company that provides services for making and receiving text messages and phone calls. It’s unclear how many Twilio employees received the SMS phishes, but the data suggest at least four Twilio employees responded to a spate of SMS phishing attempts on July 27, Aug. 2, and Aug. 7.

On that last date, Twilio disclosed that on Aug. 4 it became aware of unauthorized access to information related to a limited number of Twilio customer accounts through a sophisticated social engineering attack designed to steal employee credentials.

“This broad based attack against our employee base succeeded in fooling some employees into providing their credentials,” Twilio said. “The attackers then used the stolen credentials to gain access to some of our internal systems, where they were able to access certain customer data.”

That “certain customer data” included information on roughly 1,900 users of the secure messaging app Signal, which relied on Twilio to provide phone number verification services. In its disclosure on the incident, Signal said that with their access to Twilio’s internal tools the attackers were able to re-register those users’ phone numbers to another device.

On Aug. 25, food delivery service DoorDash disclosed that a “sophisticated phishing attack” on a third-party vendor allowed attackers to gain access to some of DoorDash’s internal company tools. DoorDash said intruders stole information on a “small percentage” of users that have since been notified. TechCrunch reported last week that the incident was linked to the same phishing campaign that targeted Twilio.

This phishing gang apparently had great success targeting employees of all the major mobile wireless providers, but most especially T-Mobile. Between July 10 and July 16, dozens of T-Mobile employees fell for the phishing messages and provided their remote access credentials.

“Credential theft continues to be an ongoing issue in our industry as wireless providers are constantly battling bad actors that are focused on finding new ways to pursue illegal activities like this,” T-Mobile said in a statement. “Our tools and teams worked as designed to quickly identify and respond to this large-scale smishing attack earlier this year that targeted many companies. We continue to work to prevent these types of attacks and will continue to evolve and improve our approach.”

This same group saw hundreds of responses from employees at some of the largest customer support and staffing firms, including Teleperformanceusa.com, Sitel.com and Sykes.com. Teleperformance did not respond to requests for comment. KrebsOnSecurity did hear from Christopher Knauer, global chief security officer at Sitel Group, the customer support giant that recently acquired Sykes. Knauer said the attacks leveraged newly-registered domains and asked employees to approve upcoming changes to their work schedules.

Knauer said the attackers set up the phishing domains just minutes in advance of spamming links to those domains in phony SMS alerts to targeted employees. He said such tactics largely sidestep automated alerts generated by companies that monitor brand names for signs of new phishing domains being registered.

“They were using the domains as soon as they became available,” Knauer said. “The alerting services don’t often let you know until 24 hours after a domain has been registered.”

On July 28 and again on Aug. 7, several employees at email delivery firm Mailchimp provided their remote access credentials to this phishing group. According to an Aug. 12 blog post, the attackers used their access to Mailchimp employee accounts to steal data from 214 customers involved in cryptocurrency and finance.

On Aug. 15, the hosting company DigitalOcean published a blog post saying it had severed ties with MailChimp after its Mailchimp account was compromised. DigitalOcean said the MailChimp incident resulted in a “very small number” of DigitalOcean customers experiencing attempted compromises of their accounts through password resets.

According to interviews with multiple companies hit by the group, the attackers are mostly interested in stealing access to cryptocurrency, and to companies that manage communications with people interested in cryptocurrency investing. In an Aug. 3 blog post from email and SMS marketing firm Klaviyo.com, the company’s CEO recounted how the phishers gained access to the company’s internal tools, and used that to download information on 38 crypto-related accounts.

The ubiquity of mobile phones became a lifeline for many companies trying to manage their remote employees throughout the Coronavirus pandemic. But these same mobile devices are fast becoming a liability for organizations that use them for phishable forms of multi-factor authentication, such as one-time codes generated by a mobile app or delivered via SMS.

Because as we can see from the success of this phishing group, this type of data extraction is now being massively automated, and employee authentication compromises can quickly lead to security and privacy risks for the employer’s partners or for anyone in their supply chain.

Unfortunately, a great many companies still rely on SMS for employee multi-factor authentication. According to a report this year from Okta, 47 percent of workforce customers deploy SMS and voice factors for multi-factor authentication. That’s down from 53 percent that did so in 2018, Okta found.

Some companies (like Knauer’s Sitel) have taken to requiring that all remote access to internal networks be managed through work-issued laptops and/or mobile devices, which are loaded with custom profiles that can’t be accessed through other devices.

Others are moving away from SMS and one-time code apps and toward requiring employees to use physical FIDO multi-factor authentication devices such as security keys, which can neutralize phishing attacks because any stolen credentials can’t be used unless the phishers also have physical access to the user’s security key or mobile device.

This came in handy for Twitter, which announced last year that it was moving all of its employees to using security keys, and/or biometric authentication via their mobile device. The phishers’ Telegram bot reported that on June 16, 2022, five employees at Twitter gave away their work credentials. In response to questions from KrebsOnSecurity, Twitter confirmed several employees were relieved of their employee usernames and passwords, but that its security key requirement prevented the phishers from abusing that information.

Twitter accelerated its plans to improve employee authentication following the July 2020 security incident, wherein several employees were phished and relieved of credentials for Twitter’s internal tools. In that intrusion, the attackers used Twitter’s tools to hijack accounts for some of the world’s most recognizable public figures, executives and celebrities — forcing those accounts to tweet out links to bitcoin scams.

“Security keys can differentiate legitimate sites from malicious ones and block phishing attempts that SMS 2FA or one-time password (OTP) verification codes would not,” Twitter said in an Oct. 2021 post about the change. “To deploy security keys internally at Twitter, we migrated from a variety of phishable 2FA methods to using security keys as our only supported 2FA method on internal systems.”

Update, 6:02 p.m. ET: Clarified that Cloudflare does not rely on TOTP (one-time multi-factor authentication codes) as a second factor for employee authentication.

“Downthem” DDoS-for-Hire Boss Gets 2 Years in Prison

A 33-year-old Illinois man was sentenced to two years in prison today following his conviction last year for operating services that allowed paying customers to launch powerful distributed denial-of-service (DDoS) attacks against hundreds of thousands of Internet users and websites.

Matthew Gatrel of St. Charles, Ill. was found guilty for violations of the Computer Fraud and Abuse Act (CFAA) related to his operation of downthem[.]org and ampnode[.]com, two DDoS-for-hire services that had thousands of customers who paid to launch more than 200,000 attacks.

Despite admitting to FBI agents that he ran these so-called “booter” services (and turning over plenty of incriminating evidence in the process), Gatrel opted to take his case to trial, defended the entire time by public defenders. Gatrel’s co-defendant and partner in the business, Juan “Severon” Martinez of Pasadena, Calif., pleaded guilty just before the trial.

After a nine-day trial in the Central District of California, Gatrel was convicted on all three counts, including conspiracy to commit unauthorized impairment of a protected computer, conspiracy to commit wire fraud, and unauthorized impairment of a protected computer.

Prosecutors said Downthem sold subscriptions allowing customers to launch DDoS attacks, while AmpNode provided “bulletproof” server hosting to customers — with an emphasis on “spoofing” servers that could be pre-configured with DDoS attack scripts and lists of vulnerable “attack amplifiers” used to launch simultaneous cyberattacks on victims.

Booter and stresser services let customers pick from among a variety of attack methods, but almost universally the most powerful of these methods involves what’s known as a “reflective amplification attack.” In such assaults, the perpetrators leverage unmanaged Domain Name Servers (DNS) or other devices on the Web to create huge traffic floods.

Ideally, DNS servers only provide services to machines within a trusted domain — such as translating an Internet address from a series of numbers into a domain name, like example.com. But DNS reflection attacks rely on consumer and business routers and other devices equipped with DNS servers that are (mis)configured to accept queries from anywhere on the Web.

Attackers can send spoofed DNS queries to these DNS servers, forging the request so that it appears to come from the target’s network. That way, when the DNS servers respond, they reply to the spoofed (target) address.

The bad guys also can amplify a reflective attack by crafting DNS queries so that the responses are much bigger than the requests. For example, an attacker could compose a DNS request of less than 100 bytes, prompting a response that is 60-70 times as large. This “amplification” effect is especially pronounced if the perpetrators query dozens of DNS servers with these spoofed requests simultaneously.

The government charged that Gatrel and Martinez constantly scanned the Internet for these misconfigured devices, and then sold lists of Internet addresses tied to these devices to other booter service operators.

“Gatrel ran a criminal enterprise designed around launching hundreds of thousands of cyber-attacks on behalf of hundreds of customers,” prosecutors wrote in a memorandum submitted in advance of his sentencing. “He also provided infrastructure and resources for other cybercriminals to run their own businesses launching these same kinds of attacks. These attacks victimized wide swaths of American society and compromised computers around the world.”

The U.S. and United Kingdom have been trying to impress on would-be customers of these booter services that hiring them for DDoS attacks is illegal. The U.K. has even taken out Google ads to remind U.K. residents when they search online for terms common to booter services.

The case against Gatrel and Martinez was brought as part of a widespread crackdown on booter services in 2018, when the FBI joined law enforcement partners overseas to seize 15 different booter service domains.

Those actions have prompted a flurry of prosecutions, with wildly varying sentences when the booter service owners are invariably found guilty. However, DDoS experts say booter and stresser services that remain in operation continue to account for the vast majority of DDoS attacks launched daily around the globe.