Posts Tagged: LinkedIn breach


7
Sep 16

The Limits of SMS for 2-Factor Authentication

A recent ping from a reader reminded me that I’ve been meaning to blog about the security limitations of using cell phone text messages for two-factor authentication online. The reader’s daughter had received a text message claiming to be from Google, warning that her Gmail account had been locked because someone in India had tried to access her account. The young woman was advised to expect a 6-digit verification code to be sent to her and to reply to the scammer’s message with that code.

2faMark Cobb, a computer technician in Reno, Nev., said had his daughter fallen for the ruse, her Gmail account would indeed have been completely compromised, and she really would have been locked out of her account because the crooks would have changed her password straight away.

Cobb’s daughter received the scam text message because she’d enabled 2-factor authentication on her Gmail account, selecting the option to have Google request that she enter a 6-digit code texted to her cell phone each time it detects a login from an unknown computer or location (in practice, the code is to be entered on the Gmail site, not sent in any kind of texted or emailed reply).

In this case, the thieves already had her password — most likely because she re-used it on some other site that got hacked. Cobb says he and his daughter believe her mobile number and password may have been exposed as part of the 2012 breach at LinkedIn.

In any case, the crooks were priming her to expect a code and to repeat it back to them because that code was the only thing standing in the way of their seizing control over her account. And they could control when Google would send the code to her phone because Google would do this as soon as they tried to log in using her username and password. Indeed, the timing aspect of this attack helps make it more believable to the target.

This is a fairly clever — if not novel — attack, and it’s one I’d wager would likely fool a decent percentage of users who have enabled text messages as a form of two-factor authentication. Certainly, text messaging is far from the strongest form of 2-factor authentication, but it is better than allowing a login with nothing more than a username and password, as this scam illustrates.

Nevertheless, text messaging codes to users isn’t the safest way to do two-factor authentication, even if some entities — like the U.S. Social Security Administration and Sony’s Playstation network — are just getting around to offering two-factor via SMS.

But don’t take my word for it. That’s according to the National Institute of Standards and Technology (NIST), which recently issued new proposed digital authentication guidelines urging organizations to favor other forms of two-factor — such as time-base one-time passwords generated by mobile apps — over text messaging. By the way, NIST is seeking feedback on these recommendations.

If anyone’s interested, Sophos’s Naked Security blog has a very readable breakdown of what’s new in the NIST guidelines. Among my favorite highlights is this broad directive: Favor the user.

“To begin with, make your password policies user friendly and put the burden on the verifier when possible,” Sophos’s Chester Wisniewski writes. “In other words, we need to stop asking users to do things that aren’t actually improving security.” Like expiring passwords and making users change them frequently, for example.

Okay, so the geeks-in-chief are saying it’s time to move away from texting as a form of 2-factor authentication. And, of course, they’re right, because text messages are a lot like email, in that it’s difficult to tell who really sent the message, and the message itself is sent in plain text — i.e. is readable by anyone who happens to be lurking in the middle.

But security experts and many technology enthusiasts have a tendency to think that everyone should see the world through the lens of security, whereas most mere mortal users just want to get on with their lives and are perfectly content to use the same password across multiple sites — regardless of how many times they’re told not to do so. Continue reading →


6
Jun 16

Password Re-user? Get Ready to Get Busy

In the wake of megabreaches at some of the Internet’s most-recognized destinations, don’t be surprised if you receive password reset requests from numerous companies that didn’t experience a breach: Some big name companies — including Facebook and Netflix — are in the habit of combing through huge data leak troves for credentials that match those of their customers and then forcing a password reset for those users.

Netflix sent out notices to customers who re-used their Netflix password at other sites that were hacked.

Netflix sent out notices to customers who re-used their Netflix password at other sites that were hacked. This notice was shared by a reader who had re-used his Netflix password at one of the breached companies.

Netflix.com, for example, sent out a notification late last week to users who made the mistake of re-using their Netflix password at Linkedin, Tumblr or MySpace. All of three of those breaches are years old, but the scope of the intrusions (more than a half billion usernames and passwords leaked in total) only became apparent recently when the credentials were posted online at various sites and services.

“We believe your Netflix account credentials may have been included in a recent release of email addresses and passwords from an older breach at another company,” the message from Neflix reads. “Just to be safe, we’ve reset your password as a precautionary measure.”

The missive goes on to urge recipients to visit Netflix.com and click the “forgot your email or password” link to reset their passwords.

Netflix is taking this step because it knows from experience that cybercriminals will be using the credentials leaked from Tumblr, MySpace and LinkedIn to see if they work on a variety of third-party sites (including Netflix).

As I wrote last year in the aftermath of the AshleyMadison breach that exposed tens of millions of user credentials, Netflix’s forensics team has been using a tool that the company released in 2014 called Scumblr, which scours high-profile sites for specific terms and data.

“Some Netflix members have received emails encouraging them to change their account passwords as a precautionary measure due to the recent disclosure of additional credentials from an older breach at another internet company,” Netflix said in a statement released to KrebsOnSecurity. “Note that we are always engaged in these types of proactive security measures (leveraging Scumblr in addition to other mechanisms and data sources), not just in the case of major security breaches such as this one.”

Continue reading →


2
Jun 16

Dropbox Smeared in Week of Megabreaches

Last week, LifeLock and several other identity theft protection firms erroneously alerted their customers to a breach at cloud storage giant Dropbox.com — an incident that reportedly exposed some 73 million usernames and passwords. The only problem with that notification was that Dropbox didn’t have a breach; the data appears instead to have come from another breach revealed this week at social network Tumblr.

Today’s post examines some of the missteps that preceded this embarrassing and potentially brand-damaging “oops.” We’ll also explore the limits of automated threat intelligence gathering in an era of megabreaches like the ones revealed over the past week that exposed more than a half billion usernames and passwords stolen from Tumblr, MySpace and LinkedIn.

The credentials leaked in connection with breaches at those social networking sites were stolen years ago, but the full extent of the intrusions only became clear recently — when several huge archives of email addresses and hashed passwords from each service were posted to the dark web and to file-sharing sites.

Last week, a reader referred me to a post by a guy named Andrew on the dropbox.com help forum. Andrew said he’d just received alerts blasted out by two different credit monitoring firms that his dropbox credentials had been compromised and were found online (see screenshot below).

A user on the dropbox forum complains of receiving alerts from separate companies warning of a huge password breach at dropbox.com.

A user on the dropbox forum complains of receiving alerts from separate companies warning of a huge password breach at dropbox.com.

Here’s what LifeLock sent out on May 23, 2016 to many customers who pay for the company’s credential recovery services:

Alert Date: 05-23-2016
Alert Type: Monitoring
Alert Category: Internet-Black Market Website
**Member has received a File Sharing Network alert Email: *****
Password: ****************************************
Where your data was found: social media
Type of Compromise: breach
Breached Sector: business
Breached Site: www.dropbox.com
Breached Record Count: 73361477
Password Status: hashed
Severity: red|email,password
Site: www.dropbox.com

LifeLock said it got the alert data via an information sharing agreement with a third party threat intelligence service, but it declined to name the service that sent the false positive alert.

“We can confirm that we recently notified a small segment of LifeLock members that a version of their dropbox.com credentials were detected on the internet,” LifeLock said in a written statement provided to KrebsOnSecurity. “When we are notified about this type of information from a partner, it is usually a “list” that is being given away, traded or sold on the dark web. The safety and security of our members’ data is our highest priority. We are continuing to monitor for any activity within our source network. At this time, we recommend that these LifeLock members change their Dropbox password(s) as a precautionary measure.”

Dropbox says it didn’t have a breach, and if it had the company would be seeing huge amounts of account checking activity and other oddities going on right now. And that’s just not happening, they say.

“We have learned that LifeLock and MyIdCare.com are reporting that Dropbox account details of some of their customers are potentially compromised,” said Patrick Heim, head of trust and security at Dropbox. “An initial investigation into these reports has found no evidence of Dropbox accounts being impacted. We’re continuing to look into this issue and will update our users if we find evidence that Dropbox accounts have been impacted.” Continue reading →


18
May 16

As Scope of 2012 Breach Expands, LinkedIn to Again Reset Passwords for Some Users

A 2012 data breach that was thought to have exposed 6.5 million hashed passwords for LinkedIn users instead likely impacted more than 117 million accounts, the company now says. In response, the business networking giant said today that it would once again force a password reset for individual users thought to be impacted in the expanded breach.

leakedinThe 2012 breach was first exposed when a hacker posted a list of some 6.5 million unique passwords to a popular forum where members volunteer or can be hired to hack complex passwords. Forum members managed to crack some the passwords, and eventually noticed that an inordinate number of the passwords they were able to crack contained some variation of “linkedin” in them.

LinkedIn responded by forcing a password reset on all 6.5 million of the impacted accounts, but it stopped there. But earlier today, reports surfaced about a sales thread on an online cybercrime bazaar in which the seller offered to sell 117 million records stolen in the 2012 breach. In addition, the paid hacked data search engine LeakedSource claims to have a searchable copy of the 117 million record database (this service said it found my LinkedIn email address in the data cache, but it asked me to pay $4.00 for a one-day trial membership in order to view the data; I declined).

Inexplicably, LinkedIn’s response to the most recent breach is to repeat the mistake it made with original breach, by once again forcing a password reset for only a subset of its users.

“Yesterday, we became aware of an additional set of data that had just been released that claims to be email and hashed password combinations of more than 100 million LinkedIn members from that same theft in 2012,” wrote Cory Scott, in a post on the company’s blog. “We are taking immediate steps to invalidate the passwords of the accounts impacted, and we will contact those members to reset their passwords. We have no indication that this is as a result of a new security breach.”

LinkedIn spokesman Hani Durzy said the company has obtained a copy of the 117 million record database, and that LinkedIn believes it to be real.

“We believe it is from the 2012 breach,” Durzy said in an email to KrebsOnSecurity. “How many of those 117m are active and current is still being investigated.”

Regarding the decision not to force a password reset across the board back in 2012, Durzy said “We did at the time what we thought was in the best interest of our member base as a whole, trying to balance security for those with passwords that were compromised while not disrupting the LinkedIn experience for those who didn’t appear impacted.”

The 117 million figure makes sense: LinkedIn says it has more than 400 million users, but reports suggest only about 25 percent of those accounts are used monthly. Continue reading →