In September 2023, KrebsOnSecurity published findings from security researchers who concluded that a series of six-figure cyberheists across dozens of victims resulted from thieves cracking master passwords stolen from the password manager service LastPass in 2022. In a court filing this week, U.S. federal agents investigating a spectacular $150 million cryptocurrency heist said they had reached the same conclusion.

On March 6, federal prosecutors in northern California said they seized approximately $24 million worth of cryptocurrencies that were clawed back following a $150 million cyberheist on Jan. 30, 2024. The complaint refers to the person robbed only as “Victim-1,” but according to blockchain security researcher ZachXBT the theft was perpetrated against Chris Larsen, the co-founder of the cryptocurrency platform Ripple.

ZachXBT was the first to report on the heist, of which approximately $24 million was frozen by the feds before it could be withdrawn. This week’s action by the government merely allows investigators to officially seize the frozen funds.

But there is an important conclusion in this seizure document: It basically says the U.S. Secret Service and the FBI agree with the findings of the LastPass breach story published here in September 2023. That piece quoted security researchers who said they were witnessing six-figure crypto heists several times each month that they believed all appeared to be the result of crooks cracking master passwords for the password vaults stolen from LastPass in 2022.

“The Federal Bureau of Investigation has been investigating these data breaches, and law enforcement agents investigating the instant case have spoken with FBI agents about their investigation,” reads the seizure complaint, which was written by a U.S. Secret Service agent. “From those conversations, law enforcement agents in this case learned that the stolen data and passwords that were stored in several victims’ online password manager accounts were used to illegally, and without authorization, access the victims’ electronic accounts and steal information, cryptocurrency, and other data.”

The document continues:

“Based on this investigation, law enforcement had probable cause to believe the same attackers behind the above-described commercial online password manager attack used a stolen password held in Victim 1’s online password manager account and, without authorization, accessed his cryptocurrency wallet/account.”

Working with dozens of victims, security researchers Nick Bax and Taylor Monahan found that none of the six-figure cyberheist victims appeared to have suffered the sorts of attacks that typically preface a high-dollar crypto theft, such as the compromise of one’s email and/or mobile phone accounts, or SIM-swapping attacks.

They discovered the victims all had something else in common: Each had at one point stored their cryptocurrency seed phrase — the secret code that lets anyone gain access to your cryptocurrency holdings — in the “Secure Notes” area of their LastPass account prior to the 2022 breaches at the company.

Bax and Monahan found another common theme with these robberies: They all followed a similar pattern of cashing out, rapidly moving stolen funds to a dizzying number of drop accounts scattered across various cryptocurrency exchanges.

According to the government, a similar level of complexity was present in the $150 million heist against the Ripple co-founder last year.

“The scale of a theft and rapid dissipation of funds would have required the efforts of multiple malicious actors, and was consistent with the online password manager breaches and attack on other victims whose cryptocurrency was stolen,” the government wrote. “For these reasons, law enforcement agents believe the cryptocurrency stolen from Victim 1 was committed by the same attackers who conducted the attack on the online password manager, and cryptocurrency thefts from other similarly situated victims.”

Reached for comment, LastPass said it has seen no definitive proof — from federal investigators or others — that the cyberheists in question were linked to the LastPass breaches.

“Since we initially disclosed this incident back in 2022, LastPass has worked in close cooperation with multiple representatives from law enforcement,” LastPass said in a written statement. “To date, our law enforcement partners have not made us aware of any conclusive evidence that connects any crypto thefts to our incident. In the meantime, we have been investing heavily in enhancing our security measures and will continue to do so.”

On August 25, 2022, LastPass CEO Karim Toubba told users the company had detected unusual activity in its software development environment, and that the intruders stole some source code and proprietary LastPass technical information. On Sept. 15, 2022, LastPass said an investigation into the August breach determined the attacker did not access any customer data or password vaults.

But on Nov. 30, 2022, LastPass notified customers about another, far more serious security incident that the company said leveraged data stolen in the August breach. LastPass disclosed that criminal hackers had compromised encrypted copies of some password vaults, as well as other personal information.

Experts say the breach would have given thieves “offline” access to encrypted password vaults, theoretically allowing them all the time in the world to try to crack some of the weaker master passwords using powerful systems that can attempt millions of password guesses per second.

Researchers found that many of the cyberheist victims had chosen master passwords with relatively low complexity, and were among LastPass’s oldest customers. That’s because legacy LastPass users were more likely to have master passwords that were protected with far fewer “iterations,” which refers to the number of times your password is run through the company’s encryption routines. In general, the more iterations, the longer it takes an offline attacker to crack your master password.

Over the years, LastPass forced new users to pick longer and more complex master passwords, and they increased the number of iterations on multiple occasions by several orders of magnitude. But researchers found strong indications that LastPass never succeeded in upgrading many of its older customers to the newer password requirements and protections.

Asked about LastPass’s continuing denials, Bax said that after the initial warning in our 2023 story, he naively hoped people would migrate their funds to new cryptocurrency wallets.

“While some did, the continued thefts underscore how much more needs to be done,” Bax told KrebsOnSecurity. “It’s validating to see the Secret Service and FBI corroborate our findings, but I’d much rather see fewer of these hacks in the first place. ZachXBT and SEAL 911 reported yet another wave of thefts as recently as December, showing the threat is still very real.”

Monahan said LastPass still hasn’t alerted their customers that their secrets—especially those stored in “Secure Notes”—may be at risk.

“Its been two and a half years since LastPass was first breached [and] hundreds of millions of dollars has been stolen from individuals and companies around the globe,” Monahan said. “They could have encouraged users to rotate their credentials. They could’ve prevented millions and millions of dollars from being stolen by these threat actors. But  instead they chose to deny that their customers were are risk and blame the victims instead.”