Wednesday, 1 May 2019

After account hacks, Twitch streamers take security into their own hands

Twitch has an account hacking problem.

After the breach of popular browser game Town of Salem in January, some 7.8 million stolen passwords quickly became the weakest link not only for the game but gamers’ other accounts. The passwords were stored using a long-deprecated scrambling algorithm, making them easily cracked.

It didn’t take long for security researcher and gamer Matthew Jakubowski to see the aftermath.

In the weeks following, the main subreddit for Amazon-owned game streaming site Twitch — of which Jakubowski is a moderator — was flooded with complaints about account hijacks. One after the other, users said their accounts had been hacked. Many of the hijacked accounts had used their Town of Salem password for their Twitch account.

Jakubowski blamed the attacks on automated account takeovers — bots that cycle through password lists stolen from breached sites, including Town of Salem.

“Twitch knows it’s a problem — but this has been going on for months and there’s no end in sight,” Jakubowski told TechCrunch.

Credential stuffing is a security problem that requires participation from both tech companies and their users. Hackers take lists of usernames and passwords from other breached sites and brute-force their way into other accounts. Customers of DoorDash and Chipotle have in recent months complained of account breaches, but have denied their systems have been hacked, offered little help to their users or shown any effort to bolster their security, and instead washed their hands of any responsibility.

Jakubowski, working with fellow security researcher Johnny Xmas, said Twitch no longer accepting email addresses to log in and incentivizing users to set up two-factor authentication would all but eliminate the problem.

The Russia connection

In new research out Tuesday, Jakubowski and Xmas said Russian hackers are a likely culprit.

The researchers found attackers would run massive lists of stolen credentials against Twitch’s login systems using widely available automation tools. With no discernible system to prevent automated logins, the attackers can hack into Twitch accounts at speed. Once logged in, the attackers then change the password to gain persistent access to the account. Even if they’re caught, some users are claiming a turnaround time of four weeks for Twitch support to get their accounts back.

On the accounts with a stored payment card — or an associated Amazon Prime membership — the attackers follow streaming channels they run or pay a small fee to access, of which Twitch takes a cut. Twitch also has its own virtual currency — bits — to help streamers solicit donations, which can be abused by the attackers to funnel funds into their coffers.

When the attacker’s streaming account hits the payout limit, the attacker cashes out.

The researchers said the attackers stream prerecorded gameplay footage on their own Twitch channels, often using Russian words and names.

“You’ll see these Russian accounts that will stream what appears to be old video game footage — you’ll never see a face or hear anybody talking but you’ll get tons of people subscribing and following in the channel,” said Xmas. “You’ll get people donating bits when nothing is going on in there — even when the channel isn’t streaming,” he said.

This activity helps cloak the attackers’ account takeover and pay-to-follow activity, said Xmas, but the attackers would keep the subscriber counts low enough to garner payouts from Twitch but not draw attention.

“If it’s something easy enough for [Jakubowski] to stumble across, it should be easy for Twitch to handle,” said Xmas. “But Twitch is staying silent and users are constantly being defrauded.”

Two-factor all the things

Twitch, unlike other sites and services with a credential stuffing problem, already lets its 15 million daily users set up two-factor authentication on their accounts, putting much of the onus to stay secure on the users themselves.

Twitch partners, like Jakubowski, and affiliates are required to set up two-factor on their accounts.

But the researchers say Twitch should do more to incentivize ordinary users — the primary target for account hijackers and fraudsters — to secure their accounts.

“I think [Twitch] doesn’t want that extra step between a valid user trying to pay for something and adding friction to that process,” said Jakubowski.

“The hackers have no idea how valuable an account is until they log in. They’re just going to try everyone — and take a shotgun approach.”
Matthew Jakubowski, security researcher and Twitch partner

“Two-factor is important — everyone knows it’s important but users still aren’t using it because it’s inconvenient,” said Xmas. “That’s the bottom line: Twitch doesn’t want to inconvenience people because that loses Twitch money,” he said.

Recognizing there was still a lack of awareness around password security and with no help from Twitch, Jakubowski and Xmas took matters into their own hands. The pair teamed up to write a comprehensive Twitch user security guide to explain why seemingly unremarkable accounts are a target for hackers, and hosted a Reddit “ask me anything” to let users to ask questions and get instant feedback.

Even during Jakubowski’s streaming sessions, he doesn’t waste a chance to warn his viewers about the security problem — often fielding other security-related questions from his fans.

“Every 10 minutes or so, I’ll remind people watching to set-up two factor,” he said.

“The hackers have no idea how valuable an account is until they log in,” said Jakubowski. “They’re just going to try everyone — and take a shotgun approach,” he said.

Xmas said users “don’t realize” how vulnerable they are. “They don’t understand why their account — which they don’t even use to stream — is desirable to hackers,” he said. “If you have a payment card associated with your account, that’s what they want.”

Carrot and the stick

Jakubowski said that convincing the users is the big challenge.

Twitch could encourage users with free perks — like badges or emotes — costing the company nothing, the researchers said. Twitch lets users collect badges to flair their accounts. World of Warcraft maker Blizzard offers perks for setting up two-factor, and Epic Games offers similar incentives to their gamers.

“Rewarding users for implementing two-factor would go a huge way,” said Xmas. “It’s incredible to see how effective that is.”

The two said the company could also integrate third-party leaked credential monitoring services, like Have I Been Pwned, to warn users if their passwords have been leaked or exposed. And, among other fixes, the researchers say removing two-factor by text message would reduce SIM swapping attacks. Xmas, who serves as director of field engineering at anti-bot startup Kasada — which TechCrunch profiled earlier this year — said Twitch could invest in systems that detect bot activity to prevent automated logins.

Twitch, when reached prior to publication, did not comment.

Jakubowski said until Twitch acts, streamers can do their part by encouraging their viewers to switch on the security feature. “Streamers are influencers — more users are likely to switch on two-factor if they hear it from a streamer,” he said.

“Getting more streamers to get on board with security will hopefully go a much longer way,” he said.

Read more:

https://tcrn.ch/2Wfp08r

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