Cybercriminals in Japan are targeting iPhone users with an online scam that tricks them into installing a malicious application when they attempt to view porn videos.
This type of attack, known as one-click fraud, is not new and has been used for years against Windows, Mac and Android users. However, what's interesting in this particular case is that it works even against non-jailbroken iPhones.
Apple tightly controls how iOS apps are distributed to users by forcing developers to publish them on the official App Store where they are subject to Apple's review procedures. However, there are exceptions to this rule in the form of special development programs for which participants have to pay extra.
One such program is called the iOS Developer Program and has an annual membership fee of US$99. Developers enrolled in this program can distribute apps over the air, outside of the official App Store, but there are some restrictions. They can only distribute apps in this manner to 100 devices per year and the unique IDs (UDID) of those devices need to be registered in advance.
Another program that's more flexible, but also more expensive, is called the iOS Developer Enterprise Program. It is intended for companies who develop their own apps and want to install them on their employees' iOS devices without publishing them on the App Store. Participation in this program costs US$299 per year.
Researchers from antivirus vendor Symantec believe that Japanese cybercriminals are abusing the iOS Developer Enterprise Program in their latest one-click fraud campaign, even though they don't have confirmation yet.
"They could have either applied for membership on their own or compromised someone else's account," the researchers said Tuesday in a blog post.
Both those possibilities are bad. If attackers applied for membership, it would mean that the US$299 price is no longer a high enough barrier for them. As long as they can infect a large number of devices quickly and profit from them, it's worth it for attackers to pay that entry price even if Apple will likely revoke their developer ID when the attack is discovered.
If they used a compromised account, that might inspire others to do the same. That would be bad news for companies because demand for stolen developer accounts enrolled in the iOS Developer Enterprise Program would grow on the underground market.
The rogue app used in this fraud campaign requires user confirmation before it's installed. If that's obtained, the app will claim that the user has subscribed to an adult video site and needs to pay 99,000 Japanese yen (almost $800) over the next three days, or the price will go up to 300,000 yen ($2,400).
It's easy to see how that can be profitable. If a single victim pays $800, the attackers already make back the money paid for enrolling in the iOS Developer Enterprise Program, plus a $500 profit.