Scammers are using invoices sent through PayPal.com to trick recipients into calling a number to dispute a pending charge. The missives — which come from Paypal.com and include a link at Paypal.com that displays an invoice for the supposed transaction — state that the user’s account is about to be charged hundreds of dollars. Recipients who call the supplied toll-free number to contest the transaction are soon asked to download software that lets the scammers assume remote control over their computer.

KrebsOnSecurity recently heard from a reader who received an email from paypal.com that he immediately suspected was phony. The message’s subject read, “Billing Department of PayPal updated your invoice.”

While the phishing message attached to the invoice is somewhat awkwardly worded, there are many convincing aspects of this hybrid scam. For starters, all of the links in the email lead to paypal.com. Hovering over the “View and Pay Invoice” button shows the button indeed wants to load a link at paypal.com, and clicking that link indeed brings up an active invoice at paypal.com.

Also, the email headers in the phishing message (PDF) show that it passed all email validation checks as being sent by PayPal, and that it was sent through an Internet address assigned to PayPal.

Both the email and the invoice state that “there is evidence that your PayPal account has been accessed unlawfully.” The message continues:

“$600.00 has been debited to your account for the Walmart Gift Card purchase. This transaction will appear in the automatically deducted amount on PayPal activity after 24 hours. If you suspect you did not make this transaction, immediately contact us at the toll-free number….”

Here’s the invoice that popped up when the “View and Pay Invoice” button was clicked:

The reader who shared this phishing email said he logged into his PayPal account and could find no signs of the invoice in question. A call to the toll-free number listed in the invoice was received by a man who answered the phone as generic “customer service,” instead of trying to spoof PayPal or Walmart. Very quickly into the conversation he suggested visiting a site called globalquicksupport[.]com to download a remote administration tool. It was clear then where the rest of this call was going.

I can see this scam tricking a great many people, especially since both the email and invoice are sent through PayPal’s systems — which practically guarantees that the message will be successfully delivered. The invoices appear to have been sent from a compromised or fraudulent PayPal Business account, which allows users to send invoices like the one shown above. Details of this scam were shared Wednesday with PayPal’s anti-abuse (phish@paypal.com) and media relations teams.

It’s remarkable how well today’s fraudsters have adapted to hijacking the very same tools that financial institutions have long used to make their customers feel safe transacting online. It’s no accident that one of the most prolific scams going right now — the Zelle Fraud Scam — starts with a text message about an unauthorized payment that appears to come from your bank. After all, financial institutions have spent years encouraging customers to sign up for mobile alerts via SMS about suspicious transactions, and to expect the occasional inbound call about possibly fraudulent transactions.

Also, today’s scammers are less interested in stealing your PayPal login than they are in phishing your entire computer and online life with remote administration software, which seems to be the whole point of so many scams these days. Because why rob just one online account when you can plunder them all?

The best advice to sidestep phishing scams is to avoid clicking on links that arrive unbidden in emails, text messages and other mediums. Most phishing scams invoke a temporal element that warns of dire consequences should you fail to respond or act quickly. If you’re unsure whether the message is legitimate, take a deep breath and visit the site or service in question manually — ideally, using a browser bookmark to avoid potential typosquatting sites.

Earlier this month, the administrator of the cybercrime forum Breached received a cease-and-desist letter from a cybersecurity firm. The missive alleged that an auction on the site for data stolen from 10 million customers of Mexico’s second-largest bank was fake news and harming the bank’s reputation. The administrator responded to this empty threat by purchasing the stolen banking data and leaking it on the forum for everyone to download.

On August 3, 2022, someone using the alias “Holistic-K1ller” posted on Breached a thread selling data allegedly stolen from Grupo Financiero Banorte, Mexico’s second-biggest financial institution by total loans. Holistic-K1ller said the database included the full names, addresses, phone numbers, Mexican tax IDs (RFC), email addresses and balances on more than 10 million citizens.

There was no reason to believe Holistic-K1ller had fabricated their breach claim. This identity has been highly active on Breached and its predecessor RaidForums for more than two years, mostly selling databases from hacked Mexican entities. Last month, they sold customer information on 36 million customers of the Mexican phone company Telcel; in March, they sold 33,000 images of Mexican IDs — with the front picture and a selfie of each citizen. That same month, they also sold data on 1.4 million customers of Mexican lending platform Yotepresto.

But this history was either overlooked or ignored by Group-IB, the Singapore-based cybersecurity firm apparently hired by Banorte to help respond to the data breach.

“The Group-IB team has discovered a resource containing a fraudulent post offering to buy Grupo Financiero Banorte’s leaked databases,” reads a letter the Breach administrator said they received from Group-IB. “We ask you to remove this post containing Banorte data. Thank you for your cooperation and prompt attention to this urgent matter.”

The administrator of Breached is “Pompompurin,” the same individual who alerted this author in November 2021 to a glaring security hole in a U.S. Justice Department website that was used to spoof security alerts from the FBI. In a post to Breached on Aug. 8, Pompompurin said they bought the Banorte database from Hacker-K1ller’s sales thread because Group-IB was sending emails complaining about it.

“They also attempted to submit DMCA’s against the website,” Pompompurin wrote, referring to legal takedown requests under the Digital Millennium Copyright Act. “Make sure to tell Banorte that now they need to worry about the data being leaked instead of just being sold.”

Banorte did not respond to requests for comment. Nor did Group-IB. But in a brief written statement picked up on Twitter, Banorte said there was no breach involving their infrastructure, and the data being sold is old.

“There has been no violation of our platforms and technological infrastructure,” Banorte said. “The set of information referred to is inaccurate and outdated, and does not put our users and customers at risk.”

That statement may be 100 percent true. Still, it is difficult to think of a better example of how not to do breach response. Banorte shrugging off this incident as a nothingburger is baffling: While it is almost certainly true that the bank balance information in the Banorte leak is now out of date, the rest of the information (tax IDs, phone numbers, email addresses) is harder to change.

“Is there one person from our community that think sending cease and desist letter to a hackers forum operator is a good idea?,” asked Ohad Zaidenberg, founder of CTI League, a volunteer emergency response community that emerged in 2020 to help fight COVID-19 related scams. “Who does it? Instead of helping, they pushed the organization from the hill.”

Kurt Seifried, director of IT for the CloudSecurityAlliance, was similarly perplexed by the response to the Banorte breach.

“If the data wasn’t real….did the bank think a cease and desist would result in the listing being removed?” Seifried wondered on Twitter. “I mean, isn’t selling breach data a worse crime usually than slander or libel? What was their thought process?”

A more typical response when a large bank suspects a breach is to approach the seller privately through an intermediary to ascertain if the information is valid and what it might cost to take it off the market. While it may seem odd to expect cybercriminals to make good on their claims to sell stolen data to only one party, removing sold stolen items from inventory is a fairly basic function of virtually all cybercriminal markets today (apart from perhaps sites that traffic in stolen identity data).

At a minimum, negotiating or simply engaging with a data seller can buy the victim organization additional time and clues with which to investigate the claim and ideally notify affected parties of a breach before the stolen data winds up online.

It is true that a large number of hacked databases put up for sale on the cybercrime underground are sold only after a small subset of in-the-know thieves have harvested all of the low-hanging fruit in the data — e.g., access to cryptocurrency accounts or user credentials that are recycled across multiple websites. And it’s certainly not unheard of for cybercriminals to go back on their word and re-sell or leak information that they have sold previously.

But companies in the throes of responding to a data security incident do themselves and customers no favors when they underestimate their adversaries, or try to intimidate cybercrooks with legal threats. Such responses generally accomplish nothing, except unnecessarily upping the stakes for everyone involved while displaying a dangerous naiveté about how the cybercrime underground works.

The Department of Homeland Security (DHS) is urging states and localities to beef up security around proprietary devices that connect to the Emergency Alert System — a national public warning system used to deliver important emergency information, such as severe weather and AMBER alerts. The DHS warning came in advance of a workshop to be held this weekend at the DEFCON security conference in Las Vegas, where a security researcher is slated to demonstrate multiple weaknesses in the nationwide alert system.

The DHS warning was prompted by security researcher Ken Pyle, a partner at security firm Cybir. Pyle said he started acquiring old EAS equipment off of eBay in 2019, and that he quickly identified a number of serious security vulnerabilities in a device that is broadly used by states and localities to encode and decode EAS alert signals.

“I found all kinds of problems back then, and reported it to the DHS, FBI and the manufacturer,” Pyle said in an interview with KrebsOnSecurity. “But nothing ever happened. I decided I wasn’t going to tell anyone about it yet because I wanted to give people time to fix it.”

Pyle said he took up the research again in earnest after an angry mob stormed the U.S. Capitol on Jan. 6, 2021.

“I was sitting there thinking, ‘Holy shit, someone could start a civil war with this thing,”’ Pyle recalled. “I went back to see if this was still a problem, and it turns out it’s still a very big problem. So I decided that unless someone actually makes this public and talks about it, clearly nothing is going to be done about it.”

The EAS encoder/decoder devices Pyle acquired were made by Lyndonville, NY-based Digital Alert Systems (formerly Monroe Electronics, Inc.), which issued a security advisory this month saying it released patches in 2019 to fix the flaws reported by Pyle, but that some customers are still running outdated versions of the device’s firmware. That may be because the patches were included in version 4 of the firmware for the EAS devices, and many older models apparently do not support the new software.

“The vulnerabilities identified present a potentially serious risk, and we believe both were addressed in software updates issued beginning Oct 2019,” EAS said in a written statement. “We also provided attribution for the researcher’s responsible disclosure, allowing us to rectify the matters before making any public statements. We are aware that some users have not taken corrective actions and updated their software and should immediately take action to update the latest software version to ensure they are not at risk. Anything lower than version 4.1 should be updated immediately. On July 20, 2022, the researcher referred to other potential issues, and we trust the researcher will provide more detail. We will evaluate and work to issue any necessary mitigations as quickly as possible.”

But Pyle said a great many EAS stakeholders are still ignoring basic advice from the manufacturer, such as changing default passwords and placing the devices behind a firewall, not directly exposing them to the Internet, and restricting access only to trusted hosts and networks.

Pyle said the biggest threat to the security of the EAS is that an attacker would only need to compromise a single EAS station to send out alerts locally that can be picked up by other EAS systems and retransmitted across the nation.

“The process for alerts is automated in most cases, hence, obtaining access to a device will allow you to pivot around,” he said. “There’s no centralized control of the EAS because these devices are designed such that someone locally can issue an alert, but there’s no central control over whether I am the one person who can send or whatever. If you are a local operator, you can send out nationwide alerts. That’s how easy it is to do this.”

One of the Digital Alert Systems devices Pyle sourced from an electronics recycler earlier this year was non-functioning, but whoever discarded it neglected to wipe the hard drive embedded in the machine. Pyle soon discovered the device contained the private cryptographic keys and other credentials needed to send alerts through Comcast, the nation’s third-largest cable company.

“I can issue and create my own alert here, which has all the valid checks or whatever for being a real alert station,” Pyle said in an interview earlier this month. “I can create a message that will start propagating through the EAS.”

Comcast told KrebsOnSecurity that “a third-party device used to deliver EAS alerts was lost in transit by a trusted shipping provider between two Comcast locations and subsequently obtained by a cybersecurity researcher.

“We’ve conducted a thorough investigation of this matter and have determined that no customer data, and no sensitive Comcast data, were compromised,” Comcast spokesperson David McGuire said.

The company said it also confirmed that the information included on the device can no longer be used to send false messages to Comcast customers or used to compromise devices within Comcast’s network, including EAS devices.

“We are taking steps to further ensure secure transfer of such devices going forward,” McGuire said. “Separately, we have conducted a thorough audit of all EAS devices on our network and confirmed that they are updated with currently available patches and are therefore not vulnerable to recently reported security issues. We’re grateful for the responsible disclosure and to the security research community for continuing to engage and share information with our teams to make our products and technologies ever more secure. Mr. Pyle informed us promptly of his research and worked with us as we took steps to validate his findings and ensure the security of our systems.”

Unauthorized EAS broadcast alerts have happened enough that there is a chronicle of EAS compromises over at fandom.com. Thankfully, most of these incidents have involved fairly obvious hoaxes.

According to the EAS wiki, in February 2013, hackers broke into the EAS networks in Great Falls, Mt. and Marquette, Mich. to broadcast an alert that zombies had risen from their graves in several counties. In Feb. 2017, an EAS station in Indiana also was hacked, with the intruders playing the same “zombies and dead bodies” audio from the 2013 incidents.

“On February 20 and February 21, 2020, Wave Broadband’s EASyCAP equipment was hacked due to the equipment’s default password not being changed,” the Wiki states. “Four alerts were broadcasted, two of which consisted of a Radiological Hazard Warning and a Required Monthly Test playing parts of the Hip Hop song Hot by artist Young Thug.”

In January 2018, Hawaii sent out an alert to cell phones, televisions and radios, warning everyone in the state that a missile was headed their way. It took 38 minutes for Hawaii to let people know the alert was a misfire, and that a draft alert was inadvertently sent. The news video clip below about the 2018 event in Hawaii does a good job of walking through how the EAS works.

A cybersecurity firm says it has intercepted a large, unique stolen data set containing the names, addresses, email addresses, phone numbers, Social Security Numbers and dates of birth on nearly 23 million Americans. The firm’s analysis of the data suggests it corresponds to current and former customers of AT&T. The telecommunications giant stopped short of saying the data wasn’t theirs, but it maintains the records do not appear to have come from its systems and may be tied to a previous data incident at another company.

Milwaukee-based cybersecurity consultancy Hold Security said it intercepted a 1.6 gigabyte compressed file on a popular dark web file-sharing site. The largest item in the archive is a 3.6 gigabyte file called “dbfull,” and it contains 28.5 million records, including 22.8 million unique email addresses and 23 million unique SSNs. There are no passwords in the database.

Hold Security founder Alex Holden said a number of patterns in the data suggest it relates to AT&T customers. For starters, email addresses ending in “att.net” accounted for 13.7 percent of all addresses in the database, with addresses from SBCGLobal.net and Bellsouth.net — both AT&T companies — making up another seven percent. In contrast, Gmail users made up more than 30 percent of the data set, with Yahoo addresses accounting for 24 percent. More than 10,000 entries in the database list “none@att.com” in the email field.

Holden’s team also examined the number of email records that included an alias in the username portion of the email, and found 293 email addresses with plus addressing. Of those, 232 included an alias that indicated the customer had signed up at some AT&T property; 190 of the aliased email addresses were “+att@”; 42 were “+uverse@,” an oddly specific reference to a DirecTV/AT&T entity that included broadband Internet. In September 2016, AT&T rebranded U-verse as AT&T Internet.

According to its website, AT&T Internet is offered in 21 states, including Alabama, Arkansas, California, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Michigan, Missouri, Nevada, North Carolina, Ohio, Oklahoma, Tennessee, Texas and Wisconsin. Nearly all of the records in the database that contain a state designation corresponded to those 21 states; all other states made up just 1.64 percent of the records, Hold Security found.

The vast majority of records in this database belong to consumers, but almost 13,000 of the entries are for corporate entities. Holden said 387 of those corporate names started with “ATT,” with various entries like “ATT PVT XLOW” appearing 81 times. And most of the addresses for these entities are AT&T corporate offices.

How old is this data? One clue may be in the dates of birth exposed in this database. There are very few records in this file with dates of birth after 2000.

“Based on these statistics, we see that the last significant number of subscribers born in March of 2000,” Holden told KrebsOnSecurity, noting that AT&T requires new account holders to be 18 years of age or older. “Therefore, it makes sense that the dataset was likely created close to March of 2018.”

There was also this anomaly: Holden said one of his analysts is an AT&T customer with a 13-letter last name, and that her AT&T bill has always had the same unique misspelling of her surname (they added yet another letter). He said the analyst’s name is identically misspelled in this database.

KrebsOnSecurity shared the large data set with AT&T, as well as Hold Security’s analysis of it. AT&T ultimately declined to say whether all of the people in the database are or were at some point AT&T customers. The company said the data appears to be several years old, and that “it’s not immediately possible to determine the percentage that may be customers.”

“This information does not appear to have come from our systems,” AT&T said in a written statement. “It may be tied to a previous data incident at another company. It is unfortunate that data can continue to surface over several years on the dark web. However, customers often receive notices after such incidents, and advice for ID theft is consistent and can be found online.”

The company declined to elaborate on what they meant by “a previous data incident at another company.”

But it seems likely that this database is related to one that went up for sale on a hacker forum on August 19, 2021. That auction ran with the title “AT&T Database +70M (SSN/DOB),” and was offered by ShinyHunters, a well-known threat actor with a long history of compromising websites and developer repositories to steal credentials or API keys.

ShinyHunters established the starting price for the auction at $200,000, but set the “flash” or “buy it now” price at $1 million. The auction also included a small sampling of the stolen information, but that sample is no longer available. The hacker forum where the ShinyHunters sales thread existed was seized by the FBI in April, and its alleged administrator arrested.

But cached copies of the auction, as recorded by cyber intelligence firm Intel 471, show ShinyHunters received bids of up to $230,000 for the entire database before they suspended the sale.

“This thread has been deleted several times,” ShinyHunters wrote in their auction discussion on Sept. 6, 2021. “Therefore, the auction is suspended. AT&T will be available on WHM as soon as they accept new vendors.”

The WHM initialism was a reference to the White House Market, a dark web marketplace that shut down in October 2021.

“In many cases, when a database is not sold, ShinyHunters will release it for free on hacker forums,” wrote BleepingComputer’s Lawrence Abrams, who broke the news of the auction last year and confronted AT&T about the hackers’ claims.

AT&T gave Abrams a similar statement, saying the data didn’t come from their systems.

“When asked whether the data may have come from a third-party partner, AT&T chose not to speculate,” Abrams wrote. “‘Given this information did not come from us, we can’t speculate on where it came from or whether it is valid,'” AT&T told BleepingComputer.

Asked to respond to AT&T’s denial, ShinyHunters told BleepingComputer at the time, “I don’t care if they don’t admit. I’m just selling.”

On June 1, 2022, a 21-year-old Frenchman was arrested in Morocco for allegedly being a member of ShinyHunters. Databreaches.net reports the defendant was arrested on an Interpol “Red Notice” at the request of a U.S. federal prosecutor from Washington state.

Databreaches.net suggests the warrant could be tied to a ShinyHunters theft in May 2020, when the group announced they had exfiltrated 500 GB of Microsoft’s source code from Microsoft’s private GitHub repositories.

“Researchers assess that Shiny Hunters gained access to roughly 1,200 private repositories around March 28, 2020, which have since been secured,” reads a May 2020 alert posted by the New Jersey Cybersecurity & Communications Integration Cell, a component within the New Jersey Office of Homeland Security and Preparedness.

“Though the breach was largely dismissed as insignificant, some images of the directory listing appear to contain source code for Azure, Office, and some Windows runtimes, and concerns have been raised regarding access to private API keys or passwords that may have been mistakenly included in some private repositories,” the alert continues. “Additionally, Shiny Hunters is flooding dark web marketplaces with breached databases.”

Last month, T-Mobile agreed to pay $350 million to settle a consolidated class action lawsuit over a breach in 2021 that affected 40 million current and former customers. The breach came to light on Aug. 16, 2021, when someone starting selling tens of millions of SSN/DOB records from T-Mobile on the same hacker forum where the ShinyHunters would post their auction for the claimed AT&T database just three days later.

T-Mobile has not disclosed many details about the “how” of last year’s breach, but it said the intruder(s) “leveraged their knowledge of technical systems, along with specialized tools and capabilities, to gain access to our testing environments and then used brute force attacks and other methods to make their way into other IT servers that included customer data.”

One way to tame your email inbox is to get in the habit of using unique email aliases when signing up for new accounts online. Adding a “+” character after the username portion of your email address — followed by a notation specific to the site you’re signing up at — lets you create an infinite number of unique email addresses tied to the same account. Aliases can help users detect breaches and fight spam. But not all websites allow aliases, and they can complicate account recovery. Here’s a look at the pros and cons of adopting a unique alias for each website.

What is an email alias? When you sign up at a site that requires an email address, think of a word or phrase that represents that site for you, and then add that prefaced by a “+” sign just to the left of the “@” sign in your email address. For instance, if I were signing up at example.com, I might give my email address as krebsonsecurity+example@gmail.com. Then, I simply go back to my inbox and create a corresponding folder called “Example,” along with a new filter that sends any email addressed to that alias to the Example folder.

Importantly, you don’t ever use this alias anywhere else. That way, if anyone other than example.com starts sending email to it, it is reasonable to assume that example.com either shared your address with others or that it got hacked and relieved of that information. Indeed, security-minded readers have often alerted KrebsOnSecurity about spam to specific aliases that suggested a breach at some website, and usually they were right, even if the company that got hacked didn’t realize it at the time.

Alex Holden, founder of the Milwaukee-based cybersecurity consultancy Hold Security, said many threat actors will scrub their distribution lists of any aliases because there is a perception that these users are more security- and privacy-focused than normal users, and are thus more likely to report spam to their aliased addresses.

Holden said freshly-hacked databases also are often scrubbed of aliases before being sold in the underground, meaning the hackers will simply remove the aliased portion of the email address.

“I can tell you that certain threat groups have rules on ‘+*@’ email address deletion,” Holden said. “We just got the largest credentials cache ever — 1 billion new credentials to us — and most of that data is altered, with aliases removed. Modifying credential data for some threat groups is normal. They spend time trying to understand the database structure and removing any red flags.”

Why might spamming aliases be a bad idea? According to the breach tracking site HaveIBeenPwned.com, only about .03 percent of the breached records in circulation today include an alias.

Email aliases are rare enough that seeing just a few email addresses with the same alias in a breached database can make it trivial to identify which company likely got hacked and leaked said database. That’s because the most common aliases are simply the name of the website where the signup takes place, or some abbreviation or shorthand for it.

Hence, for a given database, if there are more than a handful of email addresses that have the same alias, the chances are good that whatever company or website corresponds to that alias has been hacked.

That might explain the actions of Allekabels, a large Dutch electronics web shop that suffered a data breach in 2021. Allekabels said a former employee had stolen data on 5,000 customers, and that those customers were then informed about the data breach by Allekabels.

But Dutch publication RTL Nieuws said it obtained a copy of the Allekabels user database from a hacker who was selling information on 3.6 million customers at the time, and found that the 5,000 number cited by the retailer corresponded to the number of customers who’d signed up using an alias. In essence, RTL argued, the company had notified only those most likely to notice and complain that their aliased addresses were suddenly receiving spam.

“RTL Nieuws has called more than thirty people from the database to check the leaked data,” the publication explained. “The customers with such a unique email address have all received a message from Allekabels that their data has been leaked – according to Allekabels they all happened to be among the 5000 data that this ex-employee had stolen.”

HaveIBeenPwned’s Hunt arrived at the conclusion that aliases account for about .03 percent of registered email addresses by studying the data leaked in the 2013 breach at Adobe, which affected at least 38 million users. Allekabels’s ratio of aliased users was considerably higher than Adobe’s — .14 percent — but then again European Internet users tend to be more privacy-conscious.

While overall adoption of email aliases is still quite low, that may be changing. Apple customers who use iCloud to sign up for new accounts online automatically are prompted to use Apple’s Hide My Email feature, which creates the account using a unique email address that automatically forwards to a personal inbox.

What are the downsides to using email aliases, apart from the hassle of setting them up? The biggest downer is that many sites won’t let you use a “+” sign in your email address, even though this functionality is clearly spelled out in the email standard.

Also, if you use aliases, it helps to have a reliable mnemonic to remember the alias used for each account (this is a non-issue if you create a new folder or rule for each alias). That’s because knowing the email address for an account is generally a prerequisite for resetting the account’s password, and if you can’t remember the alias you added way back when you signed up, you may have limited options for recovering access to that account if you at some point forget your password.

What about you, Dear Reader? Do you rely on email aliases? If so, have they been useful? Did I neglect to mention any pros or cons? Feel free to sound off in the comments below.