Mind the gap: Google patches holes in Chrome – exploit already out there for one of them after duo spot code fix

Pair engineer malicious code from public source tweak before official binary releases

Google has updated Chrome for Linux, Mac, and Windows to address three security vulnerabilities – and exploit code for one of them is already public, so get patching.

In a release note on Monday, Krishna Govind, a test engineer at Google, said Chrome version 80.0.3987.122 addresses three flaws identified by various researchers. Each is rated high severity.

One, reported by André Bargull, is an integer-overflow bug in International Components for Unicode (ICU), a set of libraries for C/C++ and Java that handle Unicode and globalization support. This bug earned a $5,000 bounty from Google for Bargull, and no CVE has been issued.

The second flaw, reported by Sergei Glazunov of Google's Project Zero team, is an out-of-bounds memory access in the streams component of the Chromium browser. It's designated CVE-2020-6407.

The third, reported by Clement Lecigne of Google's Threat Analysis Group, is a type-confusion bug in the TurboFan compiler for V8, the open-source Chromium JavaScript engine.

This particular remote-code execution vulnerability, CVE-2020-6418, was disclosed by Lecigne to the Chromium team on February 18, and quietly fixed a day later.

Rapper Jay-Z on stage

If you're running Windows, I feel bad for you, son. Microsoft's got 99 problems, better fix each one


Interestingly enough, at the time, this public source-code tweak was spotted and studied by Exodus Intelligence researchers István Kurucsai and Vignesh Rao, who hoped to see whether it's still practical to identify security bug fixes among code changes in the Chromium source tree and develop an exploit before the patch sees an official release, a practice known as patch-gapping.

As such, Kurucsai and Rao developed proof-of-concept exploit code for CVE-2020-6418 after spotting the fix buried in the source tree, and before Google could emit an official binary release. The duo have now shared their exploit code [ZIP] which can be used by white and black hats to target those slow to patch.

The bug arises from a side-effect of the JSCreate operation and the way it handles JavaScript objects; this can be abused by a malicious webpage to execute arbitrary code within the browser sandbox. This involves modifying the length of an array to an arbitrary value to get access to the V8 memory heap. A hacker would need to break out of the sandbox to hijack a device or PC, we note.

In their write-up, Kurucsai and Rao observe that it took three days to analyze the flaw and develop exploit code. "Considering that a potential attacker would try to couple this with a sandbox escape and also work it into their own framework, it seems safe to say that one-day vulnerabilities are impractical to exploit on a weekly or bi-weekly release cycle," they said.

According to Govind, Google is keeping the discussion of the V8 bug private until the update, usually distributed automatically, reaches the majority of Chrome users. The Googler noted the we giant "is aware of reports that an exploit for CVE-2020-6418 exists in the wild."

Google's most recent Chrome zero-day fix arrived last November, when the Chocolate Factory repaired a use-after-free vulnerability (CVE-2019-13720). ®

Other stories you might like

  • US-APAC trade deal leaves out Taiwan, military defense not ruled out
    All fun and games until the chip factories are in the crosshairs

    US President Joe Biden has heralded an Indo-Pacific trade deal signed by several nations that do not include Taiwan. At the same time, Biden warned China that America would defend Taiwan from attack; it is home to a critical slice of the global chip industry, after all. 

    The agreement, known as the Indo-Pacific Economic Framework (IPEF), is still in its infancy, with today's announcement enabling the United States and the other 12 participating countries to begin negotiating "rules of the road that ensure [US businesses] can compete in the Indo-Pacific," the White House said. 

    Along with America, other IPEF signatories are Australia, Brunei, India, Indonesia, Japan, South Korea, Malaysia, New Zealand, the Philippines, Singapore, Thailand and Vietnam. Combined, the White House said, the 13 countries participating in the IPEF make up 40 percent of the global economy. 

    Continue reading
  • 381,000-plus Kubernetes API servers 'exposed to internet'
    Firewall isn't a made-up word from the Hackers movie, people

    A large number of servers running the Kubernetes API have been left exposed to the internet, which is not great: they're potentially vulnerable to abuse.

    Nonprofit security organization The Shadowserver Foundation recently scanned 454,729 systems hosting the popular open-source platform for managing and orchestrating containers, finding that more than 381,645 – or about 84 percent – are accessible via the internet to varying degrees thus providing a cracked door into a corporate network.

    "While this does not mean that these instances are fully open or vulnerable to an attack, it is likely that this level of access was not intended and these instances are an unnecessarily exposed attack surface," Shadowserver's team stressed in a write-up. "They also allow for information leakage on version and build."

    Continue reading
  • A peek into Gigabyte's GPU Arm for AI, HPC shops
    High-performance platform choices are going beyond the ubiquitous x86 standard

    Arm-based servers continue to gain momentum with Gigabyte Technology introducing a system based on Ampere's Altra processors paired with Nvidia A100 GPUs, aimed at demanding workloads such as AI training and high-performance compute (HPC) applications.

    The G492-PD0 runs either an Ampere Altra or Altra Max processor, the latter delivering 128 64-bit cores that are compatible with the Armv8.2 architecture.

    It supports 16 DDR4 DIMM slots, which would be enough space for up to 4TB of memory if all slots were filled with 256GB memory modules. The chassis also has space for no fewer than eight Nvidia A100 GPUs, which would make for a costly but very powerful system for those workloads that benefit from GPU acceleration.

    Continue reading

Biting the hand that feeds IT © 1998–2022