iOS zero-day let SolarWinds hackers compromise fully updated iPhones
By Dan Goodin
Flaw was exploited when government officials clicked on links in LinkedIn messages.
The Russian state hackers who orchestrated the SolarWinds supply chain attack last year exploited an iOS zero-day as part of a separate malicious email campaign aimed at stealing Web authentication credentials from Western European governments, according to Google and Microsoft.
In a post Google published on Wednesday, researchers Maddie Stone and Clement Lecigne said a “likely Russian government-backed actor” exploited the then-unknown vulnerability by sending messages to government officials over LinkedIn.
Moscow, Western Europe, and USAID
Attacks targeting CVE-2021-1879, as the zero-day is tracked, redirected users to domains that installed malicious payloads on fully updated iPhones. The attacks coincided with a campaign by the same hackers who delivered malware to Windows users, the researchers said.
The campaign closely tracks to one Microsoft disclosed in May. In that instance, Microsoft said that Nobelium—the name the company uses to identify the hackers behind the SolarWinds supply chain attack—first managed to compromise an account belonging to USAID, a US government agency that administers civilian foreign aid and development assistance. With control of the agency’s account for online marketing company Constant Contact, the hackers could send emails that appeared to use addresses known to belong to the US agency.
The federal government has attributed last year’s supply chain attack to hackers working for Russia’s Foreign Intelligence Service (abbreviated as SVR). For more than a decade, the SVR has conducted malware campaigns targeting governments, political think tanks, and other organizations in countries like Germany, Uzbekistan, South Korea, and the US. Targets have included the US State Department and the White House in 2014. Other names used to identify the group include APT29, the Dukes, and Cozy Bear.
In an email, Shane Huntley, the head of Google's Threat Analysis Group, confirmed the connection between the attacks involving USAID and the iOS zero-day, which resided in the WebKit browser engine.
“These are two different campaigns, but based on our visibility, we consider the actors behind the WebKit 0-day and the USAID campaign to be the same group of actors,” Huntley wrote. “It is important to note that everyone draws actor boundaries differently. In this particular case, we are aligned with the US and UK governments' assessment of APT 29.”
Forget the sandbox
Throughout the campaign, Microsoft said, Nobelium experimented with multiple attack variations. In one wave, a Nobelium-controlled web server profiled devices that visited it to determine what OS and hardware the devices ran on. If the targeted device was an iPhone or iPad, a server used an exploit for CVE-2021-1879, which allowed hackers to deliver a universal cross-site scripting attack. Apple patched the zero-day in late March.
In Wednesday’s post, Stone and Lecigne wrote:
After several validation checks to ensure the device being exploited was a real device, the final payload would be served to exploit CVE-2021-1879. This exploit would turn off Same-Origin-Policy protections in order to collect authentication cookies from several popular websites, including Google, Microsoft, LinkedIn, Facebook, and Yahoo and send them via WebSocket to an attacker-controlled IP. The victim would need to have a session open on these websites from Safari for cookies to be successfully exfiltrated. There was no sandbox escape or implant delivered via this exploit. The exploit targeted iOS versions 12.4 through 13.7. This type of attack, described by Amy Burnett in Forget the Sandbox Escape: Abusing Browsers from Code Execution, is mitigated in browsers with Site Isolation enabled, such as Chrome or Firefox.
It’s raining zero-days
The iOS attacks are part of a recent explosion in the use of zero-days. In the first half of this year, Google’s Project Zero vulnerability research group has recorded 33 zero-day exploits used in attacks—11 more than the total number from 2020. The growth has several causes, including better detection by defenders and better software defenses that require multiple exploits to break through.
The other big driver is the increased supply of zero-days from private companies selling exploits.
“0-day capabilities used to be only the tools of select nation-states who had the technical expertise to find 0-day vulnerabilities, develop them into exploits, and then strategically operationalize their use,” the Google researchers wrote. “In the mid-to-late 2010s, more private companies have joined the marketplace selling these 0-day capabilities. No longer do groups need to have the technical expertise; now they just need resources.”
The iOS vulnerability was one of four in-the-wild zero-days Google detailed on Wednesday. The other three were:
The four exploits were used in three different campaigns. Based on their analysis, the researchers assess that three of the exploits were developed by the same commercial surveillance company, which sold them to two different government-backed actors. The researchers didn’t identify the surveillance company, the governments, or the specific three zero-days they were referring to.
Representatives from Apple didn’t immediately respond to a request for comment.