The recent discovery of exploit chains targeting Apple iOS is the latest example of how cyber criminals can successfully operate malicious campaigns, undetected, through the use of zero-day vulnerabilities.
In this scenario, a threat actor or actors operated multiple compromised websites, using at least one or more zero-day vulnerabilities and numerous unique exploit chains and known vulnerabilities to compromise iPhones, even the latest versions of the operating system, for more than two years. It takes remarkable talent and resources to operate this kind of infrastructure without being detected, as potentially thousands of users were compromised without the campaign being identified.
Every villain necessitates a hero, and this campaign underscores the importance of threat research and responsible vulnerability disclosure. Cyber criminals are getting faster, smarter, and more dangerous with each day that passes. The collective power of a global community of researchers working together to identify and disclose critical vulnerabilities, such as those used in this attack, is an important way to make meaningful progress towards eliminating these types of malicious campaigns. Equally as important is dissecting attacks in their aftermath to expose unique and interesting characteristics and empower defenders and developers to mitigate these threats in the future. With that said, let’s take a look.
An Attack Hiding in Plain Sight
This Apple iOS attack is unique in that the implant was not operating stealthily and was uploading information without encryption. This means a user monitoring their network traffic would notice activity as their information was being uploaded to the attacker’s server in cleartext.
Further, there appears to be debug messages left in the code, so a user connecting their phone to their computer and reviewing console logs, would notice activity as well.
However, given the “closed” operating system on the iPhone, a user would need to take the extra step of connecting their phone to their computer in order to notice these attack indicators. Given this, even a power user would be likely to remain unaware of an infection.
The Value of iOS Exploits
Finding Apple iOS exploits in general is challenging due to the proprietary codebase and modern security mitigations. However, the type of exploits that require no user interaction and result in full remote code execution are the most rare, valuable, and difficult to uncover.
Adding further complexity to the attack, many mobile device exploits today require more than a single vulnerability to be successful; in many cases, 3-4 bugs are required to achieve elevated remote code execution on a target system. This is typically due to mitigations such as sandboxes/containers, restrictions on code execution, and reduced user privileges, making a chain of vulnerabilities necessary. This complexity reduces the success rate of an attack based on the likelihood of one or more of the bugs being discovered and “burned,” or patched out by the vendor.
Apple is a strong player in the responsible disclosure arena, recently expanding its offering of up to $1 million USD for certain vulnerabilities. Vulnerability brokers, who resell vulnerabilities, will reportedly pay up to 3 million USD for zero-interaction remote code execution vulnerabilities on iOS. It’s easy to understand the value of bugs that don’t require interaction from the victim and result in full remote code execution. With the popularity of Apple iOS across mobile devices and laptops, even these prices may be not be enough to encourage threat actors to choose to responsibly disclose their findings over more nefarious purposes.
The Power of Vulnerability Disclosure
Two of the most significant questions the Apple iOS threat discovery raises are how was this adversary able to operate for so long, primarily using known exploits, and what kind of impact were they able to achieve?
These questions bring us full circle to the value of vulnerability disclosure. Through hardware and software analysis and responsible disclosure, meaningful progress can be made towards exposing these types of vulnerabilities before they can be leveraged by bad actors for nefarious purposes.
(The authors Steve Povolny is Head of Advanced Threat Research at McAfee and Philippe Laulheret, Senior Security Researcher, McAfee Advanced Threat Research)