Same zero-day flaws had been patched earlier in iOS as well

3 Min Read

Apple has rolled out security updates to fix a trio of critical zero-day vulnerabilities in the El Capitan and Yosemite versions of its desktop operating system and its Safari web browser.

The company had earlier issued patches to fix the same set of issues in versions of its iOS operating system for iPhones and iPads.

Security researchers at the University of Toronto’s Citizen Lab and Lookout disclosed the vulnerabilities last month in a troubling report that also detailed how a shadowy firm named the NSO Group had been exploiting the flaws for years to spy on targeted individuals.

The flaws, collectively dubbed Trident, exist at the kernel level. One is a base mapping vulnerability that leaks information useful to attackers. The second is a memory corruption flaw that allows attackers to jailbreak a vulnerable device. The third flaw exists in the Safari Webkit and allows attackers to take control of a device by getting the user to click on a single link.

The NSO Group has been exploiting Trident using a highly sophisticated spyware tool dubbed Pegasus, the researchers from Citizen Lab and Lookout had said in their report. The researchers described Pegasus as a highly configurable piece of software designed to collect a wide variety of information from infected devices including call records, messages, email content and logs from applications like Gmail, Skype, Facebook, WhatsApp and FaceTime.

“Pegasus is highly advanced in its use of zero-days, obfuscation, encryption, and kernel-level exploitation,” the researchers had warned in their report.

Over the past few years, the NSO Group had either directly used Pegasus, or made it available to others, to spy on targeted individuals. Among them was a noted human rights activist in the United Arab Emirates, a journalist covering government corruption topics in Mexico and several individuals in Kenya.

The alert from Lookout and Citizen Lab only referenced the vulnerabilities as existing in versions of Apple’s iOS operating system. It made no reference to the possibility of the same flaws existing in the OS X desktop versions of the operating system as well.

Apple’s security patches this week show that Trident is a problem for users running the El Capitan and Yosemite operating system versions as well.

The updates are for OS X El Capitan v10.11.6 and OS X Yosemite v10.10.5. In its alert, Apple described one of the kernel flaws as an input validation issue, which could lead to kernel memory leaks. The issue has been addressed through “improved input sanitization,” the company noted.

The second flaw is a memory corruption issue that could allow an attacker to run arbitrary code at the kernel level. Apple has bolstered the memory handling capabilities of the affected OS versions to handle the issue.

The patch for the Safari web browser meanwhile addresses an issue that enables arbitrary code execution when a user visits maliciously crafted websites, according to the company.

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About the Author(s)

Jai Vijayan, Contributing Writer

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year career at Computerworld, Jai also covered a variety of other technology topics, including big data, Hadoop, Internet of Things, e-voting, and data analytics. Prior to Computerworld, Jai covered technology issues for The Economic Times in Bangalore, India. Jai has a Master's degree in Statistics and lives in Naperville, Ill.

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