How Researchers Cracked an 11-Year-Old Password to a $3 Million Crypto Wallet

Two years ago when “Michael,” an owner of cryptocurrency, contacted Joe Grand to help recover access to about $2 million worth of bitcoin he stored in encrypted format on his computer, Grand turned him down.

Michael, who is based in Europe and asked to remain anonymous, stored the cryptocurrency in a password-protected digital wallet. He generated a password using the RoboForm password manager and stored that password in a file encrypted with a tool called TrueCrypt. At some point, that file got corrupted and Michael lost access to the 20-character password he had generated to secure his 43.6 BTC (worth a total of about €4,000, or $5,300, in 2013). Michael used the RoboForm password manager to generate the password but did not store it in his manager. He worried that someone would hack his computer and obtain the password.

“At [that] time, I was really paranoid with my security,” he laughs.

Grand is a famed hardware hacker who in 2022 helped another crypto wallet owner recover access to $2 million in cryptocurrency he thought he’d lost forever after forgetting the PIN to his Trezor wallet. Since then, dozens of people have contacted Grand to help them recover their treasure. But Grand, known by the hacker handle “Kingpin,” turns down most of them, for various reasons.

Grand is an electrical engineer who began hacking computing hardware at age 10 and in 2008 cohosted the Discovery Channel’s Prototype This show. He now consults with companies that build complex digital systems to help them understand how hardware hackers like him might subvert their systems. He cracked the Trezor wallet in 2022 using complex hardware techniques that forced the USB-style wallet to reveal its password.

But Michael stored his cryptocurrency in a software-based wallet, which meant none of Grand’s hardware skills were relevant this time. He considered brute-forcing Michael’s password—writing a script to automatically guess millions of possible passwords to find the correct one—but determined this wasn’t feasible. He briefly considered that the RoboForm password manager Michael used to generate his password might have a flaw in the way it generated passwords, which would allow him to guess the password more easily. Grand, however, doubted such a flaw existed.

Michael contacted multiple people who specialize in cracking cryptography; they all told him “there’s no chance” of retrieving his money. But last June he approached Grand again, hoping to convince him to help, and this time Grand agreed to give it a try, working with a friend named Bruno in Germany who also hacks digital wallets.

Grand and Bruno spent months reverse engineering the version of the RoboForm program that they thought Michael had used in 2013 and found that the pseudo-random number generator used to generate passwords in that version—and subsequent versions until 2015—did indeed have a significant flaw that made the random number generator not so random. The RoboForm program unwisely tied the random passwords it generated to the date and time on the user’s computer—it determined the computer’s date and time, and then generated passwords that were predictable. If you knew the date and time and other parameters, you could compute any password that would have been generated on a certain date and time in the past.

If Michael knew the day or general time frame in 2013 when he generated it, as well as the parameters he used to generate the password (for example, the number of characters in the password, including lower- and upper-case letters, figures, and special characters), this would narrow the possible password guesses to a manageable number. Then they could hijack the RoboForm function responsible for checking the date and time on a computer and get it to travel back in time, believing the current date was a day in the 2013 time frame when Michael generated his password. RoboForm would then spit out the same passwords it generated on the days in 2013.

There was one problem: Michael couldn’t remember when he created the password.

According to the log on his software wallet, Michael moved bitcoin into his wallet for the first time on April 14, 2013. But he couldn’t remember if he generated the password the same day or some time before or after this. So, looking at the parameters of other passwords he generated using RoboForm, Grand and Bruno configured RoboForm to generate 20-character passwords with upper- and lower-case letters, numbers, and eight special characters from March 1 to April 20, 2013.

It failed to generate the right password. So Grand and Bruno lengthened the time frame from April 20 to June 1, 2013, using the same parameters. Still no luck.

Michael says they kept coming back to him, asking if he was sure about the parameters he’d used. He stuck to his first answer.

“They really annoyed me, because who knows what I did 10 years ago,” he recalls. He found other passwords he generated with RoboForm in 2013, and two of them did not use special characters, so Grand and Bruno adjusted. Last November, they reached out to Michael to set up a meeting in person. “I thought, ‘Oh my God, they will ask me again for the settings.”

Instead, they revealed that they had finally found the correct password—no special characters. It was generated on May 15, 2013, at 4:10:40 pm GMT.

“We ultimately got lucky that our parameters and time range was right. If either of those were wrong, we would have … continued to take guesses/shots in the dark,” Grand says in an email to WIRED. “It would have taken significantly longer to precompute all the possible passwords.”

Grand and Bruno created a video to explain the technical details more thoroughly.

RoboForm, made by US-based Siber Systems, was one of the first password managers on the market, and currently has more than 6 million users worldwide, according to a company report. In 2015, Siber seemed to fix the RoboForm password manager. In a cursory glance, Grand and Bruno couldn’t find any sign that the pseudo-random number generator in the 2015 version used the computer’s time, which makes them think they removed it to fix the flaw, though Grand says they would need to examine it more thoroughly to be certain.

Siber Systems confirmed to WIRED that it did fix the issue with version 7.9.14 of RoboForm, released June 10, 2015, but a spokesperson wouldn’t answer questions about how it did so. In a changelog on the company’s website, it mentions only that Siber programmers made changes to “increase randomness of generated passwords,” but it doesn’t say how they did this. Siber spokesman Simon Davis says that “RoboForm 7 was discontinued in 2017.”

Grand says that, without knowing how Siber fixed the issue, attackers may still be able to regenerate passwords generated by versions of RoboForm released before the fix in 2015. He’s also not sure if current versions contain the problem.

“I’m still not sure I would trust it without knowing how they actually improved the password generation in more recent versions,” he says. “I’m not sure if RoboForm knew how bad this particular weakness was.”

Customers may also still be using passwords that were generated with the early versions of the program before the fix. It doesn’t appear that Siber ever notified customers when it released the fixed version 7.9.14 in 2015 that they should generate new passwords for critical accounts or data. The company didn’t respond to a question about this.

If Siber didn’t inform customers, this would mean that anyone like Michael who used RoboForm to generate passwords prior to 2015—and are still using those passwords—may have vulnerable passwords that hackers can regenerate.

“We know that most people don’t change passwords unless they’re prompted to do so,” Grand says. “Out of 935 passwords in my password manager (not RoboForm), 220 of them are from 2015 and earlier, and most of them are [for] sites I still use.”

Depending on what the company did to fix the issue in 2015, newer passwords may also be vulnerable.

Last November, Grand and Bruno deducted a percentage of bitcoins from Michael’s account for the work they did, then gave him the password to access the rest. The bitcoin was worth $38,000 per coin at the time. Michael waited until it rose to $62,000 per coin and sold some of it. He now has 30 BTC, now worth $3 million, and is waiting for the value to rise to $100,000 per coin.

Michael says he was lucky that he lost the password years ago because, otherwise, he would have sold off the bitcoin when it was worth $40,000 a coin and missed out on a greater fortune.

“That I lost the password was financially a good thing.”