Phishing campaigns are a common tactic in which cybercriminals impersonate a well-known company, product, or brand to steal account credentials, financial information, or other data from unsuspecting victims. A typical phishing attack convinces the user to directly enter their password and login credentials, which are then captured by the attacker.
But a more specialized type of campaign known as consent phishing aims to grab sensitive data not by snagging your password but by tricking you into giving the necessary permissions to a malicious app. A Microsoft blog post published on Wednesday explains how it works.
SEE: Fighting social media phishing attacks: 10 tips (free PDF) (TechRepublic)
This type of consent phishing relies on the OAuth 2.0 authorization technology. By implementing the OAuth protocol into an app or website, a developer gives a user the ability to grant permission to certain data without having to enter their password or other credentials.
Used by a variety of online companies including Microsoft, Google, and Facebook, OAuth is a way to try to simplify the login and authorization process for apps and websites through a single sign-on mechanism. However, as with many technologies, OAuth can be used for both beneficial and malicious purposes.
Microsoft details the problem step by step in its blog post:
Consent screen from a sample malicious app named “Risky App.”
“OAuth has been abused since it was first deployed and its abuse is only accelerating now that it is being widely deployed,” Roger Grimes, data driven defense evangelist at KnowBe4, told TechRepublic. “Overall, it’s just hackers abusing a single point of failure. Whenever users use a single-sign-on technology, attackers are going to abuse it. Now that hundreds of millions of users use it without really knowing what it is, it makes it easier to abuse.”
The exploitation of a technology like OAuth succeeds in large part because of a lack of user knowledge and awareness.
“Part of the problem is that most users don’t understand what is happening,” Grimes said. “They don’t know that a sign-on that they’ve used with Gmail, Facebook, Twitter or some other OAuth provider is now automatically being called and used or abused by another person. They don’t understand the permission prompts either. All they know is they clicked on an email link or an attachment and now their computer system is asking them to confirm some action that they really don’t understand.”
Microsoft touted some of the steps it’s taken to try to prevent this type of malicious behavior. The company said it uses such security tools as identity and access management, device management, threat protection, and cloud security to analyze millions of data points to help detect malicious apps. Further, Microsoft is trying to better secure its application ecosystems by allowing customers to set policies on the types of apps to which users can give certain consent.
Despite the efforts of Microsoft and other companies, these attacks persist as cybercriminals stay one step ahead of the game. To help protect against consent phishing campaigns, Microsoft offers advice for individuals and organizations.
Microsoft further advised concerned organizations to check its documentation on “Detect and Remediate Illicit Consent Grants” and “Five steps to securing your identity infrastructure.”
Grimes also offered three pieces of advice for app and website developers that use OAuth:
“If you can’t do one of these three things,” Grimes added, “you’re never going to stop OAuth attacks.”
Lance Whitney is a freelance technology writer and trainer and a former IT professional. He’s written for Time, CNET, PCMag, and several other publications. He’s the author of two tech books–one on Windows and another on LinkedIn.