Category: Data Breaches

Last August, LastPass reported a security breach, saying that no customer information—or passwords—were compromised. Turns out the full story is worse:

While no customer data was accessed during the August 2022 incident, some source code and technical information were stolen from our development environment and used to target another employee, obtaining credentials and keys which were used to access and decrypt some storage volumes within the cloud-based storage service.

[…]

To date, we have determined that once the cloud storage access key and dual storage container decryption keys were obtained, the threat actor copied information from backup that contained basic customer account information and related metadata including company names, end-user names, billing addresses, email addresses, telephone numbers, and the IP addresses from which customers were accessing the LastPass service.

The threat actor was also able to copy a backup of customer vault data from the encrypted storage container which is stored in a proprietary binary format that contains both unencrypted data, such as website URLs, as well as fully-encrypted sensitive fields such as website usernames and passwords, secure notes, and form-filled data.

That’s bad. It’s not an epic disaster, though.

These encrypted fields remain secured with 256-bit AES encryption and can only be decrypted with a unique encryption key derived from each user’s master password using our Zero Knowledge architecture. As a reminder, the master password is never known to LastPass and is not stored or maintained by LastPass.

So, according to the company, if you chose a strong master password—here’s my advice on how to do it—your passwords are safe. That is, you are secure as long as your password is resilient to a brute-force attack. (That they lost customer data is another story….)

Fair enough, as far as it goes. My guess is that many LastPass users do not have strong master passwords, even though the compromise of your encrypted password file should be part of your threat model. But, even so, note this unverified tweet:

I think the situation at @LastPass may be worse than they are letting on. On Sunday the 18th, four of my wallets were compromised. The losses are not significant. Their seeds were kept, encrypted, in my lastpass vault, behind a 16 character password using all character types.

If that’s true, it means that LastPass has some backdoor—possibly unintentional—into the password databases that the hackers are accessing. (Or that @Cryptopathic’s “16 character password using all character types” is something like “P@ssw0rdP@ssw0rd.”)

My guess is that we’ll learn more during the coming days. But this should serve as a cautionary tale for anyone who is using the cloud: the cloud is another name for “someone else’s computer,” and you need to understand how much or how little you trust that computer.

If you’re changing password managers, look at my own Password Safe. Its main downside is that you can’t synch between devices, but that’s because I don’t use the cloud for anything.

News articles. Slashdot thread.

EDITED TO ADD: People choose lousy master passwords.

Millions of people likely just received an email or snail mail notice saying they’re eligible to claim a class action payment in connection with the 2017 megabreach at consumer credit bureau Equifax. Given the high volume of reader inquiries about this, it seemed worth pointing out that while this particular offer is legit (if paltry), scammers are likely to soon capitalize on public attention to the settlement money.

One reader’s copy of their Equifax Breach Settlement letter. They received a check for $6.97.

In 2017, Equifax disclosed a massive, extended data breach that led to the theft of Social Security Numbers, dates of birth, addresses and other personal information on nearly 150 million people. Following a public breach response perhaps best described as a giant dumpster fire, the big-three consumer credit reporting bureau was quickly hit with nearly two dozen class-action lawsuits.

In exchange for resolving all outstanding class action claims against it, Equifax in 2019 agreed to a settlement that includes up to $425 million to help people affected by the breach.

Affected consumers were eligible to apply for at least three years of credit monitoring via all three major bureaus simultaneously, including Equifax, Experian and Trans Union. Or, if you didn’t want to take advantage of the credit monitoring offers, you could opt for a cash payment of up to $125.

The settlement also offered reimbursement for the time you may have spent remedying identity theft or misuse of your personal information caused by the breach, or purchasing credit monitoring or credit reports. This was capped at 20 total hours at $25 per hour ($500), with total cash reimbursement payments not to exceed $20,000 per consumer.

Those who did file a claim probably started receiving emails or other communications earlier this year from the Equifax Breach Settlement Fund, which has been messaging class participants about methods of collecting their payments.

How much each recipient receives appears to vary quite a bit, but probably most people will have earned a payment on the smaller end of that $125 scale — like less than $10. Those who received higher amounts likely spent more time documenting actual losses and/or explaining how the breach affected them personally.

So far this week, KrebsOnSecurity has received at least 20 messages from readers seeking more information about these notices. Some readers shared copies of letters they got in the mail along with a paper check from the Equifax Breach Settlement Fund (see screenshot above).

Others said they got emails from the Equifax Breach Settlement domain that looked like an animated greeting card offering instructions on how to redeem a virtual prepaid card.

If you received one of these settlement emails and are wary about clicking the included links (good for you, by the way), copy the redemption code and paste it into the search box at myprepaidcenter.com/redeem. Successfully completing the card application requires accepting a prepaid MasterCard agreement (PDF).

The website for the settlement — equifaxbreachsettlement.com — also includes a lookup tool that lets visitors check whether they were affected by the breach; it requires your last name and the last six digits of your Social Security Number.

In February 2020, the U.S. Justice Department indicted four Chinese officers of the People’s Liberation Army (PLA) for perpetrating the 2017 Equifax hack. DOJ officials said the four men were responsible for carrying out the largest theft of sensitive personal information by state-sponsored hackers ever recorded.

Equifax surpassed Wall Street’s expectations in its most recently quarterly earnings: The company reported revenues of $1.24 billion for the quarter ending September 2022.

Of course, most of those earnings come from Equifax’s continued legal ability to buy and sell eye-popping amounts of financial and personal data on U.S. consumers. As one of the three major credit bureaus, Equifax collects and packages information about your credit, salary, and employment history. It tracks how many credit cards you have, how much money you owe, and how you pay your bills. Each company creates a credit report about you, and then sells this report to businesses who are deciding whether to give you credit.

Americans currently have no legal right to opt out of this data collection and trade. But you can and also should and freeze your credit, which by the way can make your credit profile less profitable for companies like Equifax — because they make money every time some potential creditor wants a peek inside your financial life. Also, it’s probably a good idea to freeze the credit of your children and/or dependents as well. It’s free on both counts.

InfraGard, a program run by the U.S. Federal Bureau of Investigation (FBI) to build cyber and physical threat information sharing partnerships with the private sector, this week saw its database of contact information on more than 80,000 members go up for sale on an English-language cybercrime forum. Meanwhile, the hackers responsible are communicating directly with members through the InfraGard portal online — using a new account under the assumed identity of a financial industry CEO that was vetted by the FBI itself.

On Dec. 10, 2022, the relatively new cybercrime forum Breached featured a bombshell new sales thread: The user database for InfraGard, including names and contact information for tens of thousands of InfraGard members.

The FBI’s InfraGard program is supposed to be a vetted Who’s Who of key people in private sector roles involving both cyber and physical security at companies that manage most of the nation’s critical infrastructures — including drinking water and power utilities, communications and financial services firms, transportation and manufacturing companies, healthcare providers, and nuclear energy firms.

“InfraGard connects critical infrastructure owners, operators, and stakeholders with the FBI to provide education, networking, and information-sharing on security threats and risks,” the FBI’s InfraGard fact sheet reads.

KrebsOnSecurity contacted the seller of the InfraGard database, a Breached forum member who uses the handle “USDoD” and whose avatar is the seal of the U.S. Department of Defense.

USDoD’s InfraGard sales thread on Breached.

USDoD said they gained access to the FBI’s InfraGard system by applying for a new account using the name, Social Security Number, date of birth  and other personal details of a chief executive officer at a company that was highly likely to be granted InfraGard membership.

The CEO in question — currently the head of a major U.S. financial corporation that has a direct impact on the creditworthiness of most Americans — did not respond to requests for comment.

USDoD told KrebsOnSecurity their phony application was submitted in November in the CEO’s name, and that the application included a contact email address that they controlled — but also the CEO’s real mobile phone number.

“When you register they said that to be approved can take at least three months,” USDoD said. “I wasn’t expected to be approve[d].”

But USDoD said that in early December, their email address in the name of the CEO received a reply saying the application had been approved (see redacted screenshot to the right). While the FBI’s InfraGard system requires multi-factor authentication by default, users can choose between receiving a one-time code via SMS or email.

“If it was only the phone I will be in [a] bad situation,” USDoD said. “Because I used the person[‘s] phone that I’m impersonating.”

USDoD said the InfraGard user data was made easily available via an Application Programming Interface (API) that is built into several key components of the website that help InfraGard members connect and communicate with each other.

USDoD said after their InfraGard membership was approved, they asked a friend to code a script in Python to query that API and retrieve all available InfraGard user data.

“InfraGard is a social media intelligence hub for high profile persons,” USDoD said. “They even got [a] forum to discuss things.”

KrebsOnSecurity shared with the FBI several screenshots and other data that may help isolate the imposter InfraGard account, but the agency declined to comment for this story.

To prove they still had access to InfraGard as of publication time Tuesday evening, USDoD sent a direct note through InfraGard’s messaging system to an InfraGard member whose personal details were initially published as a teaser on the database sales thread.

That InfraGard member, who is head of security at a major U.S. technology firm, confirmed receipt of USDoD’s message but asked to remain anonymous for this story.

USDoD acknowledged that their $50,000 asking price for the InfraGard database may be a tad high, given that it is a fairly basic list of people who are already very security-conscious. Also, only about half of the user accounts contain an email address, and most of the other database fields — like Social Security Number and Date of Birth — are completely empty.

“I don’t think someone will pay that price, but I have to [price it] a bit higher to [negotiate] the price that I want,” they explained.

While the data exposed by the infiltration at InfraGard may be minimal, the user data might not have been the true end game for the intruders.

USDoD said they were hoping the imposter account would last long enough for them to finish sending direct messages as the CEO to other executives using the InfraGuard messaging portal. USDoD shared the following redacted screenshot from what they claimed was one such message, although they provided no additional context about it.

A screenshot shared by USDoD showing a message thread in the FBI’s InfraGard system.

USDoD said in their sales thread that the guarantor for the transaction would be Pompompurin, the administrator of the cybercrime forum Breached. By purchasing the database through the forum administrator’s escrow service, would-be buyers can theoretically avoid getting ripped off and ensure the transaction will be consummated to the satisfaction of both parties before money exchanges hands.

Pompompurin has been a thorn in the side of the FBI for years. Their Breached forum is widely considered to be the second incarnation of RaidForums, a remarkably similar English-language cybercrime forum shuttered by the U.S. Department of Justice in April. Prior to its infiltration by the FBI, RaidForums sold access to more than 10 billion consumer records stolen in some of the world’s largest data breaches.

In November 2021, KrebsOnSecurity detailed how Pompompurin abused a vulnerability in an FBI online portal designed to share information with state and local law enforcement authorities, and how that access was used to blast out thousands of hoax email messages — all sent from an FBI email and Internet address.

This is a developing story. Updates will be noted here with timestamps.

I have been meaning to write about Joe Sullivan, Uber’s former Chief Security Officer. He was convicted of crimes related to covering up a cyberattack against Uber. It’s a complicated case, and I’m not convinced that he deserved a guilty ruling or that it’s a good thing for the industry.

I may still write something, but until then, this essay on the topic is worth reading.

After suffering two large, and embarrassing, data breaches in recent weeks, the Australian government increased the fine for serious data breaches from $2.2 million to a minimum of $50 million. (That’s $50 million AUD, or $32 million USD.)

This is a welcome change. The problem is one of incentives, and Australia has now increased the incentive for companies to secure the personal data or their users and customers.

It’s big:

The breach appeared to have compromised many of Uber’s internal systems, and a person claiming responsibility for the hack sent images of email, cloud storage and code repositories to cybersecurity researchers and The New York Times.

“They pretty much have full access to Uber,” said Sam Curry, a security engineer at Yuga Labs who corresponded with the person who claimed to be responsible for the breach. “This is a total compromise, from what it looks like.”

It looks like a pretty basic phishing attack; someone gave the hacker their login credentials. And because Uber has lousy internal security, lots of people have access to everything. So once a hacker gains a foothold, they have access to everything.

This is the same thing that Mudge accuses Twitter of: too many employees have broad access within the company’s network.

More details. Slashdot thread.

EDITED TO ADD (9/20): More details.

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 five employees fell for the scam (although only two employees also provided the crucial one-time MFA code).

Image: Cloudflare.com

In a blog post earlier this month, Cloudflare said it detected the account takeovers and that no Cloudflare systems were compromised. 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.

Image: Group-IB.

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.”

Twilio was hacked earlier this month, and the phone numbers of 1,900 Signal users were exposed:

Here’s what our users need to know:

  • All users can rest assured that their message history, contact lists, profile information, whom they’d blocked, and other personal data remain private and secure and were not affected.
  • For about 1,900 users, an attacker could have attempted to re-register their number to another device or learned that their number was registered to Signal. This attack has since been shut down by Twilio. 1,900 users is a very small percentage of Signal’s total users, meaning that most were not affected.

We are notifying these 1,900 users directly, and prompting them to re-register Signal on their devices.

If you were not notified, don’t worry about it. But it does bring up the old question: Why does Signal require a phone number to use? It doesn’t have to be that way.

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.

Image: Shutterstock.

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.

Hold Security found these email domains account for 87% of all domains in the data set. Nearly 21% belonged to AT&T customers.

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.

Image: Hold Security.

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.

Image: BleepingComputer

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.”

A sales thread tied to the stolen T-Mobile customer data.