The CloudFlare IPFS gateway has only recently been launched, but it is already being used by phishers to host malicious content.Cloudflare IPFS gateway phishing attacks are likely to have a high success rate, as some of the checks performed by end users to confirm the legitimacy of domains will not raise red flags.
The IPFS gateway is a P2P system that allows files to be shared easily throughout an organization and accessed through a web browser. Content is distributed to different nodes throughout the networked systems. The system can be used for creating distributed websites, and CloudFlare has made this process easier by offering free SSL certificates and allowing domains to be easily connected to IPFS.
If phishers host their phishing forms on CloudFlare IPFS, they benefit from CloudFlare’s SSL certificate. Since the phishing page will start with cloudflare-ipfs.com, this adds legitimacy. The CloudFlare-owned domain is more likely to be trusted than domains owned by phishers.
When CloudFlare IPFS Gateway phishing forms are encountered, visitors will be advised that the webpage is secure, the site starts with HTTPS, and a green padlock will be displayed. If the visitor takes the time to check certificate information of the web page, they will find it has been issued to CloudFlare-IPFS.com by CloudFlare Inc., and the certificate is valid. The browser will not display any warning and CloudFlare IPFS Gateway phishing content will therefore seem legitimate.
At least one threat actor is using the CloudFlare IPFS Gateway for phishing and is hosting forms that claim to be standard login pages for Office 365, DocuSign, Azure AD, and other cloud-based services, complete with appropriate logos.
If a visitor completes the form information, their credentials will be forwarded to the operator of a known phishing domain – searchurl.bid – and the user will be displayed a document about business models, strategy and innovation. This may also not raise a red flag.
The CloudFlare IPFS Gateway phishing strategy is similar to that used on Azure Blob storage, which also take advantage of legitimate SSL certificates. In that case the certificate is issued by Microsoft.
It is becoming increasingly important for phishers to use HTTPS for hosting phishing content. As more businesses transition from HTTP to HTTPS, and browsers such as Chrome now display warnings to users about insecure sites, phishers have similarly had to make the change to HTTPS. Both CloudFlare IPFS Gateway and Azure Blog storage offer an easy way to do this.
In both cases, links to the malicious forms are distributed through spam email. One of the most common ways to do this is to include an email attachment that contains a button which must be clicked in order to download content. The user is advised that the content of the file is secured, and that professional email login credentials must be entered in order to view the content. The document may be an invoice, purchase order, or a scanned document that needs to be reviewed.
The increase in use of cloud platforms to host phishing content makes it more important than ever for organizations to implement advanced phishing defenses. A powerful spam filter such as SpamTitan should be used to block the initial emails and prevent them from being delivered to end users’ inboxes. These phishing tactics should also be covered in security awareness training to raise awareness of the threat and to alert users that SSL certificates do not necessarily mean the content of a web page is legitimate. Web filtering solutions are also essential for blocking access to known malicious web pages, should a user visit a malicious link.