Threat actors could abuse the iOS URL Scheme to undermine user privacy and stage other attacks with respect to certain vendors’ apps.

Trend Micro observed that several iOS apps available for download in China, specifically the payment app WeChat and the retail program Suning, were susceptible to attacks involving the iOS URL Scheme. Designed by Apple as a compensating workaround to its mobile sandbox technology, the URL Scheme is a feature that allows apps to load on a iOS device using URLs. This functionality enables apps to share information with one another, all the while limiting the scope of damage if one of those apps suffered a compromise.

In its research, Trend Micro traced the danger to the fact that multiple apps could abuse the same Sample:// URL Scheme. For instance, the security firm noted that bad actors could abuse this shared Scheme to request a login token for a user’s WeChat account and abuse that token to authenticate themselves in Suning. At that point, they could steal sensitive information from and/or abuse both accounts. They could also abuse the feature to trick a user into paying other people’s bills and to launch other malicious apps.

Other Attacks Abusing the iOS URL Scheme

This isn’t the first time that researchers have spotted threat actors abusing the iOS URL Scheme. In February 2015, for instance, FireEye observed an updated version of the Masque Attack iOS flaw that it named Masque Attack II. This exploit leveraged the ability to bypass iOS prompts and hijack the native URL Scheme to intercept communications between apps and, in turn, launch phishing attacks designed to steal users’ login credentials. Later that year, Mobile Iron reported on a group of vulnerabilities called XARA that also hinged on URL Scheme hijacking with iOS devices.

Monitor App Behavior With AI Tools

Security professionals can help defend their organizations against threats that abuse the iOS URL Scheme by using artificial intelligence (AI) to monitor how apps behave across devices and analyze events in which those programs take unexpected actions. Companies should also create human partnerships and develop internal security checks and balances to defend their assets against AI-powered insider threats.