Posts Tagged: Duo Security

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 →

Jul 13

Toward A Greater Mobile Mal-Awareness

Several recent developments in mobile malware are conspiring to raise the threat level for Android users, making it easier for attackers to convert legitimate applications into malicious apps and to undermine the technology that security experts use to tell the difference.

Source: Symantec

Source: Symantec

Last week, Symantec warned about a new malware toolkit or “binder” designed to Trojanize legitimate Android apps with a backdoor that lets miscreants access infected mobile devices remotely. Binders have been around in a variety of flavors for many years, but they typically are used to backdoor Microsoft Windows applications.

Symantec notes that the point-and-click Androrat APK Binder is being used in conjunction with an open-source remote access Trojan for Android devices called called AndroRAT. “Like other RATs, it allows a remote attacker to control the infected device using a user friendly control panel,” Symantec’s Andrea Lelli wrote. “For example, when running on a device, AndroRAT can monitor and make phone calls and SMS messages, get the device’s GPS coordinates, activate and use the camera and microphone and access files stored on the device.”

The company said while it has detected only a few hundred AndroRAT infections worldwide, but that it expects that number increase as more tools for AndroRAT like the APK binder emerge.

Perhaps more worryingly, Symantec said this week that it had discovered two malicious Android apps in the wild that take advantage of a newly discovered and potentially quite serious security hole in Android applications. As first outlined roughly two weeks ago by researchers at BlueBox Security, the so-called “Master Key” vulnerability could let attackers convert almost any Android application into a Trojan, all without altering its cryptographic digital signature. Android uses these signatures to determine if an app is legitimate and to verify that an app hasn’t been tampered with or modified.

Continue reading →

Apr 13

Brute Force Attacks Build WordPress Botnet

Security experts are warning that an escalating series of online attacks designed to break into poorly-secured WordPress blogs is fueling the growth of an unusually powerful botnet currently made up of more than 90,000 Web servers.



Over the past week, analysts from a variety of security and networking firms have tracked an alarming uptick in so-called “brute force” password-guessing attacks against Web sites powered by WordPress, perhaps the most popular content management system in use today (this blog also runs WordPress).

According to Web site security firm Incapsula, those responsible for this crime campaign are scanning the Internet for WordPress installations, and then attempting to log in to the administrative console at these sites using a custom list of approximately 1,000 of the most commonly-used username and password combinations.

Incapsula co-founder Marc Gaffan told KrebsOnSecurity that infected sites will be seeded with a backdoor the lets the attackers control the site remotely (the backdoors persist regardless of whether the legitimate site owner subsequently changes his password). The infected sites then are conscripted into the attacking server botnet, and forced to launch password-guessing attacks against other sites running WordPress.

Gaffan said the traffic being generated by all this activity is wreaking havoc for some Web hosting firms.

“It’s hurting the service providers the most, not just with incoming traffic,” Gaffan said. “But as soon as those servers get hacked, they are now bombarding other servers with attack traffic. We’re talking about Web servers, not home PCs. PCs maybe connected to the Internet with a 10 megabit or 20 megabit line, but the best hosting providers have essentially unlimited Internet bandwidth. We think they’re building an army of zombies, big servers to bombard other targets for a bigger cause down the road.”

Indeed, this was the message driven home Thursday in a blog post from Houston, Texas based HostGator, one of the largest hosting providers in the United States. The company’s data suggests that the botnet of infected WordPress installations now includes more than 90,000 compromised sites.

Continue reading →