Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Endpoint

9/28/2020
09:00 AM
50%
50%

MFA-Minded Attackers Continue to Figure Out Workarounds

While MFA can improve overall security posture, it's not a "silver bullet" -- and hacks continue.

As online users become increasingly aware of and use multifactor authentication (MFA), attackers are devising new ways to circumvent the technology — and often with great success.

Earlier this month, for example, security firm Proofpoint reported its disclosure of critical vulnerabilities in Microsoft WS-Trust that could be used to circumvent MFA on cloud services that use the technology — chief among them, Microsoft 365. An attack could have allowed a cybercriminal to use credentials obtained from phishing and credential dumps to log into Office 365, Azure, and other Microsoft services, Proofpoint stated.

Related Content:

Younger Generations Drive Bulk of 2FA Adoption

State of Endpoint Security: How Enterprises Are Managing Endpoint Security Threats

New on The Edge: RASP 101: Staying Safe With Runtime Application Self-Protection

Such vulnerabilities are one way of working around the additional security provided by MFA. While security experts underscore that MFA improves the overall security of online users, exploitable vulnerabilities and poor user decisions can undermine those protections.

"When it comes to cloud security, MFA is not a silver bullet," said Or Safran, senior threat detection analysis at Proofpoint, in an analysis of the vulnerabilities. "As more organizations adopt the technology, more vulnerabilities will be discovered and abused by attackers. However, MFA can improve overall security posture, especially when combined with people-centric threat visibility and adaptive access controls."

As more people access valuable accounts online, two-factor authentication (2FA) and MFA have become more popular. In a December 2019 report, security firm Duo Security found adoption of 2FA among users had nearly doubled in two years, with 53% of survey respondents using 2FA for some of their accounts (up from 28% in 2017). More than two-thirds of younger people — 34 years old or younger — used 2FA on some accounts, while only a third of people ages 65 or older used the technology, according to the study.

The critical vulnerabilities found by Proofpoint are the latest exploitation scenarios to target the increasingly popular security technologies. Last year, the FBI warned that cybercriminals had adopted a variety of measures to workaround or circumvent MFA. In one cited example from 2019, a code injection error in a banking institution's website allowed attackers to enter "a manipulated string" into the multifactor field, instead of a PIN, and bypass the second factor, according to the FBI advisory.

Yet, while such technical bypasses are not rare, far more common are attackers' efforts to insert themselves in the MFA process and steal passcodes or security tokens. Circumventing MFA often boils down to taking advantage of credulous users, says Roger Grimes, data-driven defense analyst at KnowBe4, a security training firm.

"The broad attacks that spammers and phishers often send out to gather credentials — MFA can prevent those types of attacks," he says. "But when attackers know that the user has MFA, it often proves to not be much of a barrier and, in some cases, makes it even easier."

The most common type of MFA attack is to intercept the one-time passcode. Real-time attacks use a man-in-the-middle proxy to grab the one-time password that the user enters into what they believe to be a legitimate site. In 2019, cybersecurity researchers released a tool, dubbed Muraena, that allows the harvesting of the second factor. A common target is the widely deployed technology for sending one-time passwords via text messages, a defense so broken that the National Institute of Standards and Technology (NIST) warned against its use in May 2016

Another common approach is to steal the security token sent to the user to simplify future logins. Reusing the token can allow an attacker to access the user's account. Finally, technical attacks on the software, often targeting support for legacy security technologies, can allow widespread attacks on services protected by MFA. 

"From our perspective in monitoring email, cloud, and hybrid attacks, the largest increase in threat activity has been tied to malicious third-party apps abusing OAuth tokens, which Microsoft calls 'consent phishing,'" says Ryan Kalember, executive vice president of cybersecurity strategy at Proofpoint.

The best technologies at present to limit attacks are those based on the latest Fast Identity Online (FIDO) standard, FIDO2, which uses device identity to harden the authentication process against remote attackers, and a variety of push technologies that alert the user on a registered device of any attempted access and requires them to approve that access.

"There is a lot of crap out there, but there are also good solutions, and they are developing better solutions," KnowBe4's Grimes says. "But everything is hackable, so on top of that, you need to train your end users to recognize the attacks. Just because you have MFA does not mean that you can't be hacked."

Veteran technology journalist of more than 20 years. Former research engineer. Written for more than two dozen publications, including CNET News.com, Dark Reading, MIT's Technology Review, Popular Science, and Wired News. Five awards for journalism, including Best Deadline ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
News
Former CISA Director Chris Krebs Discusses Risk Management & Threat Intel
Kelly Sheridan, Staff Editor, Dark Reading,  2/23/2021
Edge-DRsplash-10-edge-articles
Security + Fraud Protection: Your One-Two Punch Against Cyberattacks
Joshua Goldfarb, Director of Product Management at F5,  2/23/2021
News
Cybercrime Groups More Prolific, Focus on Healthcare in 2020
Robert Lemos, Contributing Writer,  2/22/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win an Amazon Gift Card! Click Here
Latest Comment: This comment is waiting for review by our moderators.
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
Flash Poll
Building the SOC of the Future
Building the SOC of the Future
Digital transformation, cloud-focused attacks, and a worldwide pandemic. The past year has changed the way business works and the way security teams operate. There is no going back.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-27132
PUBLISHED: 2021-02-27
SerComm AG Combo VD625 AGSOT_2.1.0 devices allow CRLF injection (for HTTP header injection) in the download function via the Content-Disposition header.
CVE-2021-25284
PUBLISHED: 2021-02-27
An issue was discovered in through SaltStack Salt before 3002.5. salt.modules.cmdmod can log credentials to the info or error log level.
CVE-2021-3144
PUBLISHED: 2021-02-27
In SaltStack Salt before 3002.5, eauth tokens can be used once after expiration. (They might be used to run command against the salt master or minions.)
CVE-2021-3148
PUBLISHED: 2021-02-27
An issue was discovered in SaltStack Salt before 3002.5. Sending crafted web requests to the Salt API can result in salt.utils.thin.gen_thin() command injection because of different handling of single versus double quotes. This is related to salt/utils/thin.py.
CVE-2021-3151
PUBLISHED: 2021-02-27
i-doit before 1.16.0 is affected by Stored Cross-Site Scripting (XSS) issues that could allow remote authenticated attackers to inject arbitrary web script or HTML via C__MONITORING__CONFIG__TITLE, SM2__C__MONITORING__CONFIG__TITLE, C__MONITORING__CONFIG__PATH, SM2__C__MONITORING__CONFIG__PATH, C__M...