Malware is prevalent. Mobile malware is on the rise. We are used to the perception that Android users are always under the threat of being attacked by malware and therefore should be highly suspicious about the software they install, while iOS users are immune and can enjoy the freedom of installing whatever they want without hesitation, due to Apple’s “walled-garden” approach. Well… this isn’t exactly the case.
As I’ll further discuss in this post, there is another way to create havoc on one’s device, which may be comparable to sophisticated malware, without actually installing a program on the device.
iOS profiles, also known as mobileconfig files, are used by cellular carriers, Mobile Device Management solutions and even mobile applications, in order to configure key system-level settings of iOS devices. These include Wi-Fi, VPN, Email and APN settings, among others. While mobileconfigs are usually used for constructive needs and thus provide a lot of value, these same capabilities might be used by malicious attackers to circumvent Apple’s security model and perform significant damage to their victims.
We actually created an online demo that demonstrates the aforementioned. We believe it can give a good sense of the severity and ease of the attack. If you would like to get more information, feel free to leave us a note at firstname.lastname@example.org and we’ll gladly follow-up with you.
However, we identified another possible infection vector, which can prove to be very effective due to its reliance on the trust between customers and their service providers. A quick survey we did uncovered a variety of cellular carriers, many of them MVNOs, that ask their clients to install mobileconfig files in order to receive data plan access; unfortunately, these processes usually involve poor utilization of security measures. As part of our work, we identified a worrisome process at several AT&T stores, which is further described below. As part of our responsible disclosure process, we notified and worked with AT&T to address our findings. We would like to further mitigate the exposure for such threats by raising awareness among both AT&T and non-AT&T clients.
Due to the capabilities of mobileconfig profiles, a connection to an external resource for the purpose of downloading and installing profiles on iOS-based devices should always be thought of carefully. The specific interaction with http://unlockit.co.nz is done over plain text (without an SSL/TLS encryption layer). As well known, man in the middle attacks could be used to alter the mobileconfig downloaded to the phone, allowing the attacker to install a malicious mobileconfig on the user’s device without his/her consent or knowledge. This can be easily done by utilizing attacks such as ARP-poisoning and evil twin against the wi-fi network the customer uses for installing the profile, such as AT&T’s in-store wi-fi or an Internet cafe network.
During our discussion with AT&T’s security team on that matter, they expressed that AT&T’s formal policy does not allow prepaid iOS devices offerings. However, given the fact the AT&T stores we visited didn’t seem to follow this policy, we believe AT&T will strive to better enforce it in its stores going forward. We would like to thank AT&T’s security team for their cooperation and commitment to the security of AT&T’s customers.
If you identify a suspicious profile, we encourage you to send us the details of the profile and the origin you downloaded it from to email@example.com. We will scan it and get back to you with our findings.
+Adi Sharabani plans to present our findings at the Hertzliya conference cyber security track led by Yuval Ne’eman’s Workshop later on today – if you happen to attend the conference, you are most welcome to join us for a quick chat.