Credentials Phishing Attacks
In the last month, researchers at Menlo Security has been observing a steady rise in credential phishing attacks. This is a popular attack method where attackers make use of fake login pages or forms to steal credentials of commonly used services in a corporate environment.
Apart from commonly targeted cloud services like Office 365, Amazon Prime, Adobe and others, Menlo also noticed credential phishing attacks impersonating commonly used software services from other countries like South Korea and crypto-currency wallets.
Office365 Continues To Be The #1 Phishing Target
In the last month, it may not be a surprise to learn that the bulk of the credential phishing attacks were serving fake Outlook and Office365 login pages. This is mostly because of the ubiquity of Office365 service across the corporate sector. Other notable phishing attack incidents included:-
Phishing On Cloud Services: There is an uptick on the number of phishing pages being hosted on popular cloud services. While services like Azure, One Drive, Box, Firebase, and Dropbox continue to be leveraged to host phishing pages, one interesting addition to this list we came across last month was a phishing page hosted on the popular note taking app Evernote:
Phishing Tactics: Attackers are always trying to come up with tactics to bypass detection solutions. Below, we describe a few common tactics that are actively being used to serve phishing content.
Use of Data URLs/Encoding To Mask Content: In a specific phishing HTML page content, we observed usage of Data-URLs to:
- Hide the actual java-script code that posts credentials to a remote URL.
- Encode and embed all custom CSS/Images on the page itself
The advantages of using this mechanism is as follows:
- Allows the entire phishing page content to be rendered on a browser in a single load within the client.
- Adding the “Content-Encoding: gzip” header allows the server to send the compressed response.
- There would be no additional resource requests (Javascript/CSS/Images etc).
- This is an attempt to evade solutions that rely on the “Content-Type” header to determine resources like Javascript/CSS.
Dynamic Content Generation: One interesting tactic that was observed with an Office365 phishing campaign: this campaign seems to be appending the user’s email address on the URL, the phishing page path is dynamically generated, and the user’s email address is automatically filled.
Conclusion
Cyber criminals are trying to add complexity in order to carry out phishing campaigns that steal sensitive information. With free services like Let’s Encrypt, it’s becoming increasingly easier for attackers to host phishing sites behind SSL with a relatively short TTL for maximum hit rate.
Increasing cyber security awareness through training and education initiatives is very helpful in reducing the impact of credential phishing attacks, but corporate users should always be cautious when a site presents a form that asks for personal or sensitive information.
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