Posts Tagged: Security Keys


19
Aug 20

Voice Phishers Targeting Corporate VPNs

The COVID-19 epidemic has brought a wave of email phishing attacks that try to trick work-at-home employees into giving away credentials needed to remotely access their employers’ networks. But one increasingly brazen group of crooks is taking your standard phishing attack to the next level, marketing a voice phishing service that uses a combination of one-on-one phone calls and custom phishing sites to steal VPN credentials from employees.

According to interviews with several sources, this hybrid phishing gang has a remarkably high success rate, and operates primarily through paid requests or “bounties,” where customers seeking access to specific companies or accounts can hire them to target employees working remotely at home.

And over the past six months, the criminals responsible have created dozens if not hundreds of phishing pages targeting some of the world’s biggest corporations. For now at least, they appear to be focusing primarily on companies in the financial, telecommunications and social media industries.

“For a number of reasons, this kind of attack is really effective,” said Allison Nixon, chief research officer at New York-based cyber investigations firm Unit 221B. “Because of the Coronavirus, we have all these major corporations that previously had entire warehouses full of people who are now working remotely. As a result the attack surface has just exploded.”

TARGET: NEW HIRES

A typical engagement begins with a series of phone calls to employees working remotely at a targeted organization. The phishers will explain that they’re calling from the employer’s IT department to help troubleshoot issues with the company’s virtual private networking (VPN) technology.

The employee phishing page bofaticket[.]com. Image: urlscan.io

The goal is to convince the target either to divulge their credentials over the phone or to input them manually at a website set up by the attackers that mimics the organization’s corporate email or VPN portal.

Zack Allen is director of threat intelligence for ZeroFOX, a Baltimore-based company that helps customers detect and respond to risks found on social media and other digital channels. Allen has been working with Nixon and several dozen other researchers from various security firms to monitor the activities of this prolific phishing gang in a bid to disrupt their operations.

Allen said the attackers tend to focus on phishing new hires at targeted companies, and will often pose as new employees themselves working in the company’s IT division. To make that claim more believable, the phishers will create LinkedIn profiles and seek to connect those profiles with other employees from that same organization to support the illusion that the phony profile actually belongs to someone inside the targeted firm.

“They’ll say ‘Hey, I’m new to the company, but you can check me out on LinkedIn’ or Microsoft Teams or Slack, or whatever platform the company uses for internal communications,” Allen said. “There tends to be a lot of pretext in these conversations around the communications and work-from-home applications that companies are using. But eventually, they tell the employee they have to fix their VPN and can they please log into this website.”

SPEAR VISHING

The domains used for these pages often invoke the company’s name, followed or preceded by hyphenated terms such as “vpn,” “ticket,” “employee,” or “portal.” The phishing sites also may include working links to the organization’s other internal online resources to make the scheme seem more believable if a target starts hovering over links on the page.

Allen said a typical voice phishing or “vishing” attack by this group involves at least two perpetrators: One who is social engineering the target over the phone, and another co-conspirator who takes any credentials entered at the phishing page and quickly uses them to log in to the target company’s VPN platform in real-time.

Time is of the essence in these attacks because many companies that rely on VPNs for remote employee access also require employees to supply some type of multi-factor authentication in addition to a username and password — such as a one-time numeric code generated by a mobile app or text message. And in many cases, those codes are only good for a short duration — often measured in seconds or minutes.

But these vishers can easily sidestep that layer of protection, because their phishing pages simply request the one-time code as well.

A phishing page (helpdesk-att[.]com) targeting AT&T employees. Image: urlscan.io

Allen said it matters little to the attackers if the first few social engineering attempts fail. Most targeted employees are working from home or can be reached on a mobile device. If at first the attackers don’t succeed, they simply try again with a different employee.

And with each passing attempt, the phishers can glean important details from employees about the target’s operations, such as company-specific lingo used to describe its various online assets, or its corporate hierarchy.

Thus, each unsuccessful attempt actually teaches the fraudsters how to refine their social engineering approach with the next mark within the targeted organization, Nixon said.

“These guys are calling companies over and over, trying to learn how the corporation works from the inside,” she said. Continue reading →


11
Apr 19

Android 7.0+ Phones Can Now Double as Google Security Keys

Google this week made it easier for Android users to enable strong 2-factor authentication (2FA) when logging into Google’s various services. The company announced that all phones running Android 7.0 and higher can now be used as Security Keys, an additional authentication layer that helps thwart phishing sites and password theft.

As first disclosed by KrebsOnSecurity last summer, Google maintains it has not had any of its 85,000+ employees successfully phished on their work-related accounts since early 2017, when it began requiring all employees to use physical Security Keys in place of passwords and one-time codes.

The most commonly used Security Keys are inexpensive USB-based devices that offer an alternative approach to 2FA, which requires the user to log in to a Web site using something they know (the password) and something they have (e.g. a one-time token, key fob or mobile device).

But Google said starting this week, any mobile phone running Android 7.0+ (Nougat) can serve the same function as a USB-based security key. Once a user has enrolled their Android phone as a Security Key, the user will need to approve logins via a prompt sent to their phone after submitting their username and password at a Google login page.

Many readers have expressed confusion or skepticism about how Security Keys can prevent users from getting hooked by phishing sites or clever man-in-the-middle attacks. This capability was described in far greater visual detail in this video last year by Christiaan Brand, product manager at Google Cloud.

But the short version is that even if a user who has enrolled a Security Key for authentication tries to log in at a site pretending to be Google, the company’s systems simply refuse to request the Security Key if the user isn’t on an official Google site, and the login attempt fails.

“It puts you in this mode….[in] which is there is no other way to log in apart from the Security Key,” Brand said. “No one can trick you into a downgrade attack, no one can trick you into anything different. You need to provide a security key or you don’t get into your account.”

Google says built-in security keys are available on phones running Android 7.0+ (Nougat) with Google Play Services, enabling existing phones to act as users’ primary 2FA method for work (G Suite, Cloud Identity, and GCP) and personal Google accounts to sign in on a Bluetooth-enabled Chrome OS, macOS X, or Windows 10 device with a Chrome browser. Continue reading →


1
Aug 18

Reddit Breach Highlights Limits of SMS-Based Authentication

Reddit.com today disclosed that a data breach exposed some internal data, as well as email addresses and passwords for some Reddit users. As Web site breaches go, this one doesn’t seem too severe. What’s interesting about the incident is that it showcases once again why relying on mobile text messages (SMS) for two-factor authentication (2FA) can lull companies and end users into a false sense of security.

In a post to Reddit, the social news aggregation platform said it learned on June 19 that between June 14 and 18 an attacker compromised a several employee accounts at its cloud and source code hosting providers.

Reddit said the exposed data included internal source code as well as email addresses and obfuscated passwords for all Reddit users who registered accounts on the site prior to May 2007. The incident also exposed the email addresses of some users who had signed up to receive daily email digests of specific discussion threads.

Of particular note is that although the Reddit employee accounts tied to the breach were protected by SMS-based two-factor authentication, the intruder(s) managed to intercept that second factor.

“Already having our primary access points for code and infrastructure behind strong authentication requiring two factor authentication (2FA), we learned that SMS-based authentication is not nearly as secure as we would hope, and the main attack was via SMS intercept,” Reddit disclosed. “We point this out to encourage everyone here to move to token-based 2FA.”

Reddit didn’t specify how the SMS code was stolen, although it did say the intruders did not hack Reddit employees’ phones directly. Nevertheless, there are a variety of well established ways that attackers can intercept one-time codes sent via text message.

In one common scenario, known as a SIM-swap, the attacker masquerading as the target tricks the target’s mobile provider into tying the customer’s service to a new SIM card that the bad guys control. A SIM card is the tiny, removable chip in a mobile device that allows it to connect to the provider’s network. Customers can request a SIM swap when their existing SIM card has been damaged, or when they are switching to a different phone that requires a SIM card of another size.

Another typical scheme involves mobile number port-out scams, wherein the attacker impersonates a customer and requests that the customer’s mobile number be transferred to another mobile network provider. In both port-out and SIM swap schemes, the victim’s phone service gets shut off and any one-time codes delivered by SMS (or automated phone call) get sent to a device that the attackers control. Continue reading →


23
Jul 18

Google: Security Keys Neutralized Employee Phishing

Google has not had any of its 85,000+ employees successfully phished on their work-related accounts since early 2017, when it began requiring all employees to use physical Security Keys in place of passwords and one-time codes, the company told KrebsOnSecurity.

A YubiKey Security Key made by Yubico. The basic model featured here retails for $20.

Security Keys are inexpensive USB-based devices that offer an alternative approach to two-factor authentication (2FA), which requires the user to log in to a Web site using something they know (the password) and something they have (e.g., a mobile device).

A Google spokesperson said Security Keys now form the basis of all account access at Google.

“We have had no reported or confirmed account takeovers since implementing security keys at Google,” the spokesperson said. “Users might be asked to authenticate using their security key for many different apps/reasons. It all depends on the sensitivity of the app and the risk of the user at that point in time.”

The basic idea behind two-factor authentication is that even if thieves manage to phish or steal your password, they still cannot log in to your account unless they also hack or possess that second factor.

The most common forms of 2FA require the user to supplement a password with a one-time code sent to their mobile device via text message or an app. Indeed, prior to 2017 Google employees also relied on one-time codes generated by a mobile app — Google Authenticator.

In contrast, a Security Key implements a form of multi-factor authentication known as Universal 2nd Factor (U2F), which allows the user to complete the login process simply by inserting the USB device and pressing a button on the device. The key works without the need for any special software drivers.

Once a device is enrolled for a specific Web site that supports Security Keys, the user no longer needs to enter their password at that site (unless they try to access the same account from a different device, in which case it will ask the user to insert their key).

U2F is an emerging open source authentication standard, and as such only a handful of high-profile sites currently support it, including Dropbox, Facebook, Github (and of course Google’s various services). Most major password managers also now support U2F, including Dashlane, and Keepass. Duo Security [full disclosure: an advertiser on this site] also can be set up to work with U2F.

With any luck, more sites soon will begin incorporating the Web Authentication API — also known as “WebAuthn” — a standard put forth by the World Wide Web Consortium in collaboration with the FIDO Alliance. The beauty of WebAuthn is that it eliminates the need for users to constantly type in their passwords, which negates the threat from common password-stealing methods like phishing and man-in-the-middle attacks.

Currently, U2F is supported by Chrome, Mozilla Firefox, and Opera. In both Firefox and Quantum (the newer, faster version of Firefox), U2F is not enabled by default. To turn it on, type “about:config” in the browser bar, type or paste “security.webauth.u2f” and double-click the resulting entry to change the preference’s value from “false” to “true.”

Microsoft says it expects to roll out updates to its flagship Edge browser to support U2F later this year. According to a recent article at 9to5Mac.com, Apple has not yet said when or if it will support the standard in its Safari browser. Continue reading →