Firefox and Edge Fall to Hackers on Day Two of Pwn2Own

Browsers Firefox and Edge take a beating on day two of the Pwn2Own competition.

Hackers took down the Mozilla Firefox and Microsoft Edge browsers on Thursday at Pawn2Own, the annual hacking conference held in tandem with CanSecWest, as the competition continued for a second day.

The dynamic hacking duo of Amat Cama and Richard Zhu, which make up team Fluoroacetate, had another good day, following Wednesday’s successes. The two trained their skills first on Mozilla Firefox, leveraging a JIT bug in the browser, followed up by an out-of-bounds write exploit in the Windows kernel. The one-two punch allowed Fluoroacetate to take over the targeted system.

“They were able to execute code at SYSTEM level just by using Firefox to visit their specially crafted website,” wrote Zero Day Initiative in a write-up of the day’s hacking results. For their efforts the two earned $50,000.

View image on Twitter

View image on Twitter

Zero Day Initiative


The @fluoroacetate duo does it again. They used a type confusion in #Edge, a race condition in the kernel, then an out-of-bounds write in #VMware to go from a browser in a virtual client to executing code on the host OS. They earn $130K plus 13 Master of Pwn points.

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The story of the day continued to be Cama and Zhu, who earned an additional $130,000 for a “masterfully crafted exploit chain” that eventually lead to the owning the underlying hypervisor of a VMware Workstation, ZDI reported.

That hack began on VMware Workstation where Fluoroacetate opened an Edge browser and visited a booby-trapped website that contained a confusion bug. Next, Cama and Zhu used a race condition in the Windows kernel followed by an out-of-bounds write in VMware workstation that linked to executing code on the underlying hypervisor.

Arthur Gerkis of Exodus Intelligence

Arthur Gerkis of Exodus Intelligence

Adding both day’s awards together, Fluoroacetate has so far earned $340,000 in the Pawn2Own competition this year.

Mozilla’s Firefox browser went down a second time Thursday, thanks to hacker Niklas Baumstark. He was able to execute code at the system level of a PC by leveraging a JIT bug in Firefox.

“In a real-world scenario, an attacker could use this to run their code on a target system at the level of the logged-on user,” ZDI wrote. The successful exploit earned Baumstark $40,000.

A researcher named Arthur Gerkis, with Exodus Intelligence, was the final contestant and a newcomer to the Pwn2Own competition. His target was also Microsoft’s Edge browser. “[Gerkis] wasted no time by using a double free bug in the renderer followed by a logic bug to bypass the sandbox,” ZDI wrote. For his effort, the researcher earned $50,000.

Day three of the competition closes out the Pawn2Own event with a automotive category.

Recently Patched WinRAR Flaw Exploited in APT Attacks

A recently patched WinRAR vulnerability has been exploited by several threat groups, including advanced persistent threat (APT) actors.

The flaw, tracked as CVE-2018-20250, impacts the unacev2.dll library used by WinRAR for unpacking ACE archives. Starting with WinRAR 5.70, the problematic library has been removed to prevent abuse, but many users have failed to update the application, allowing malicious actors to continue launching attacks.

The WinRAR security hole can be exploited via specially crafted ACE archives to extract a harmless file to the destination folder selected by the user, while also extracting a malicious file to a location specified by the attacker. An attacker can achieve arbitrary code execution by extracting a piece of malware to the Windows Startup folder, ensuring that it would get executed the next time the operating system boots.

Technical details of the vulnerability, which is believed to have existed for 19 years, were made public by Check Point Software Technologies on February 20. The first attacks exploiting the vulnerability to deliver a piece of malware were spotted a few days later.

In a blog post published on Thursday, McAfee said it had spotted over 100 unique exploitstargeting the vulnerability in the first week after the flaw was disclosed. The company said most of the initial targets resided in the United States.

In one of the attacks observed by McAfee, hackers delivered an ACE file that appeared to contain a bootlegged copy of Ariana Grande’s “thank u, next” album. If the user attempts to extract the content of the archive, some MP3 files are extracted, but a piece of malware is also silently planted in the Startup folder.

The 360 Threat Intelligence Center of Chinese cybersecurity firm Qihoo 360 has also spotted several attacks, including ones that appear to have been launched by APT actors. Its researchers have seen attacks aimed at Ukraine, the Middle East (Revenge RAT delivered with bait documents referencing the United Nations), and others.

South Korean security firm ESTsecurity says it has seen APT attacks aimed at South Korean users in which hackers attempted to deliver malware with documents referencing the recent Hanoi Summit between North Korean Chairman Kim Jong-un and U.S. President Donald Trump.