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Before yesterdayKrebs on Security

Researchers Quietly Cracked Zeppelin Ransomware Keys

By BrianKrebs

Peter is an IT manager for a technology manufacturer that got hit with a Russian ransomware strain called “Zeppelin” in May 2020. He’d been on the job less than six months, and because of the way his predecessor architected things, the company’s data backups also were encrypted by Zeppelin. After two weeks of stalling their extortionists, Peter’s bosses were ready to capitulate and pay the ransom demand. Then came the unlikely call from an FBI agent. “Don’t pay,” the agent said. “We’ve found someone who can crack the encryption.”

Peter, who spoke candidly about the attack on condition of anonymity, said the FBI told him to contact a cybersecurity consulting firm in New Jersey called Unit 221B, and specifically its founder — Lance James. Zeppelin sprang onto the crimeware scene in December 2019, but it wasn’t long before James discovered multiple vulnerabilities in the malware’s encryption routines that allowed him to brute-force the decryption keys in a matter of hours, using nearly 100 cloud computer servers.

In an interview with KrebsOnSecurity, James said Unit 221B was wary of advertising its ability to crack Zeppelin ransomware keys because it didn’t want to tip its hand to Zeppelin’s creators, who were likely to modify their file encryption approach if they detected it was somehow being bypassed.

This is not an idle concern. There are multiple examples of ransomware groups doing just that after security researchers crowed about finding vulnerabilities in their ransomware code.

“The minute you announce you’ve got a decryptor for some ransomware, they change up the code,” James said.

But he said the Zeppelin group appears to have stopped spreading their ransomware code gradually over the past year, possibly because Unit 221B’s referrals from the FBI let them quietly help nearly two dozen victim organizations recover without paying their extortionists.

In a blog post published today to coincide with a Black Hat talk on their discoveries, James and co-author Joel Lathrop said they were motivated to crack Zeppelin after the ransomware gang started attacking nonprofit and charity organizations.

“What motivated us the most during the leadup to our action was the targeting of homeless shelters, nonprofits and charity organizations,” the two wrote. “These senseless acts of targeting those who are unable to respond are the motivation for this research, analysis, tools, and blog post. A general Unit 221B rule of thumb around our offices is: Don’t [REDACTED] with the homeless or sick! It will simply trigger our ADHD and we will get into that hyper-focus mode that is good if you’re a good guy, but not so great if you are an ***hole.”

The researchers said their break came when they understood that while Zeppelin used three different types of encryption keys to encrypt files, they could undo the whole scheme by factoring or computing just one of them: An ephemeral RSA-512 public key that is randomly generated on each machine it infects.

“If we can recover the RSA-512 Public Key from the registry, we can crack it and get the 256-bit AES Key that encrypts the files!” they wrote. “The challenge was that they delete the [public key] once the files are fully encrypted. Memory analysis gave us about a 5-minute window after files were encrypted to retrieve this public key.”

Unit 221B ultimately built a “Live CD” version of Linux that victims could run on infected systems to extract that RSA-512 key. From there, they would load the keys into a cluster of 800 CPUs donated by hosting giant Digital Ocean that would then start cracking them. The company also used that same donated infrastructure to help victims decrypt their data using the recovered keys.

A typical Zeppelin ransomware note.

Jon is another grateful Zeppelin ransomware victim who was aided by Unit 221B’s decryption efforts. Like Peter, Jon asked that his last name and that of his employer be omitted from the story, but he’s in charge of IT for a mid-sized managed service provider that got hit with Zeppelin in July 2020.

The attackers that savaged Jon’s company managed to phish credentials and a multi-factor authentication token for some tools the company used to support customers, and in short order they’d seized control over the servers and backups for a healthcare provider customer.

Jon said his company was reluctant to pay a ransom in part because it wasn’t clear from the hackers’ demands whether the ransom amount they demanded would provide a key to unlock all systems, and that it would do so safely.

“They want you to unlock your data with their software, but you can’t trust that,” Jon said. “You want to use your own software or someone else who’s trusted to do it.”

In August 2022, the FBI and the Cybersecurity & Infrastructure Security Agency (CISA) issued a joint warning on Zeppelin, saying the FBI had “observed instances where Zeppelin actors executed their malware multiple times within a victim’s network, resulting in the creation of different IDs or file extensions, for each instance of an attack; this results in the victim needing several unique decryption keys.”

The advisory says Zeppelin has attacked “a range of businesses and critical infrastructure organizations, including defense contractors, educational institutions, manufacturers, technology companies, and especially organizations in the healthcare and medical industries. Zeppelin actors have been known to request ransom payments in Bitcoin, with initial amounts ranging from several thousand dollars to over a million dollars.”

The FBI and CISA say the Zeppelin actors gain access to victim networks by exploiting weak Remote Desktop Protocol (RDP) credentials, exploiting SonicWall firewall vulnerabilities, and phishing campaigns. Prior to deploying Zeppelin ransomware, actors spend one to two weeks mapping or enumerating the victim network to identify data enclaves, including cloud storage and network backups, the alert notes.

Jon said he felt so lucky after connecting with James and hearing about their decryption work, that he toyed with the idea of buying a lottery ticket that day.

“This just doesn’t usually happen,” Jon said. “It’s 100 percent like winning the lottery.”

By the time Jon’s company got around to decrypting their data, they were forced by regulators to prove that no patient data had been exfiltrated from their systems. All told, it took his employer two months to fully recover from the attack.

“I definitely feel like I was ill-prepared for this attack,” Jon said. “One of the things I’ve learned from this is the importance of forming your core team and having those people who know what their roles and responsibilities are ahead of time. Also, trying to vet new vendors you’ve never met before and build trust relationships with them is very difficult to do when you have customers down hard now and they’re waiting on you to help them get back up.”

A more technical writeup on Unit 221B’s discoveries (cheekily titled “0XDEAD ZEPPELIN”) is available here.

Transacting in Person with Strangers from the Internet

By BrianKrebs

Communities like Craigslist, OfferUp, Facebook Marketplace and others are great for finding low- or no-cost stuff that one can pick up directly from a nearby seller, and for getting rid of useful things that don’t deserve to end up in a landfill. But when dealing with strangers from the Internet, there is always a risk that the person you’ve agreed to meet has other intentions.

Nearly all U.S. states now have designated safe trading stations — mostly at local police departments — which ensure that all transactions are handled in plain view of both the authorities and security cameras.

These safe trading places exist because sometimes in-person transactions from the Internet don’t end well for one or more parties involved. The website Craigslistkillers has catalogued news links for at least 132 murders linked to Craigslist transactions since 2015. Many of these killings involved high-priced items like automobiles and consumer electronics, where the prospective buyer apparently intended all along to kill the owner and steal the item offered for sale. Others were motivated simply by a desire to hurt people.

This is not to say that using Craigslist is uniquely risky or dangerous; I’m sure the vast majority of transactions generated by the site end amicably and without physical violence. And that probably holds true for all of Craigslist’s competitors.

Still, the risk of a deal going badly when one meets total strangers from the Internet is not zero, and so it’s only sensible to take a few simple precautions. For example, choosing to transact at a designated safe place such as a police station dramatically reduces the likelihood that anyone wishing you harm would even show up.

I recently stumbled upon one of these designated exchange places by accident, hence my interest in learning more about them. The one I encountered was at a Virginia county sheriff’s office, and it has two parking spots reserved with a sign that reads, “Internet Purchase & Exchange Location: This Area is Under 24 Hour Video Surveillance” [image above].

According to the list maintained at Safetradestations.com, there are four other such designated locations in Northern Virginia. And it appears most states now have them in at least some major cities. Safeexchangepoint.com also has a searchable index of safe trading locations in the United States and Canada.

Granted, not everyone is going to live close to one of these designated trading stations. Or maybe what you want to buy, sell or trade you’d rather not have recorded in front of police cameras. Either way, here are a few tips on staying safe while transacting in real life with strangers from the Internet (compliments of the aforementioned safe trading websites).

The safest exchange points are easily accessible and in a well-lit, public place where transactions are visible to others nearby. Try to arrange a meeting time that is during daylight hours, and consider bringing a friend along — especially when dealing with high-value items like laptops and smart phones.

Safeexchangepoint.com also advises that police or merchants that host their own exchange locations generally won’t get involved in the details of your transaction unless specified otherwise, and that many police departments (but not all) are willing to check the serial number of an item for sale to make sure it’s not known to be stolen property.

Of course, it’s not always practical or possible to haul that old sofa to the local police department, or a used car that isn’t working. In those situations, safetradestations.com has some decent suggestions:

  • Meet at a police station where you can exchange and photocopy each others’ identification papers, such as a driver’s license. Do NOT carry cash to this location.
  • Photocopy the license or identification paper, or use your phone to photograph it.
  • Email the ID information to a friend, or to someone trusted (not to yourself).
  • If you’re selling at home, or going to someone’s home, never be outnumbered. If you’re at home, make sure you have two or three people there — and tell the person who is coming that you will have others with you.
  • At home or an apartment, NEVER let someone go anywhere unaccompanied. Always make sure they are escorted.
  • Never let more than one group come to your home at one time to buy or sell.
  • Beware of common scams, like checks for an amount higher than the amount of the deal; “cashier’s checks” that are forged and presented when the bank is closed.
  • If you are given a cashier’s check, money order or other equivalent, call the bank — at the number listed online, not a number the buyer gives you — to verify the validity of the check.

It Might Be Our Data, But It’s Not Our Breach

By BrianKrebs

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 an 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.

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

By BrianKrebs

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.

The user interface for Downthem[.]org.

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.

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