Google Online Security Blog

Announcing the Chrome Browser Full Chain Exploit Bonus

June 1, 2023

Amy Ressler, Chrome Security Team on behalf of the Chrome VRP For 13 years, a key pillar of the Chrome Security ecosystem has included encouraging security researchers to find security vulnerabilities in Chrome browser and report them to us, through the Chrome Vulnerability Rewards Program. Starting today and until 1 December 2023, the first security bug report we receive with a functional full chain exploit, resulting in a Chrome sandbox escape, is eligible for triple the full reward amount. Your full chain exploit could result in a reward up to $180,000 (potentially more with other bonuses). Any subsequent full chains submitted during this time are eligible for double the full reward amount! We have historically put a premium on reports with exploits – “high quality reports with a functional exploit” is the highest tier of reward amounts in our Vulnerability Rewards Program. Over the years, the threat model of Chrome browser has evolved as features have matured and new features and new mitigations, such a MiraclePtr, have been introduced. Given these evolutions, we’re always interested in explorations of new and novel approaches to fully exploit Chrome browser and we want to provide opportunities to better incentivize this type of research. These exploits provide us valuable insight into the potential attack vectors for exploiting Chrome, and allow us to identify strategies for better hardening specific Chrome features and ideas for future broad-scale mitigation strategies. The full details of this bonus opportunity are available on the Chrome VRP rules and rewards page. The summary is as follows:

The bug reports may be submitted in advance while exploit development continues during this 180-day window. The functional exploits must be submitted to Chrome by the end of the 180-day window to be eligible for the triple or double reward.

The first functional full chain exploit we receive is eligible for the triple reward amount.

The full chain exploit must result in a Chrome browser sandbox escape, with a demonstration of attacker control / code execution outside of the sandbox.

Exploitation must be able to be performed remotely and no or very limited reliance on user interaction.

The exploit must have been functional in an active release channel of Chrome (Dev, Beta, Stable, Extended Stable) at the time of the initial reports of the bugs in that chain. Please do not submit exploits developed from publicly disclosed security bugs or other artifacts in old, past versions of Chrome.

As is consistent with our general rewards policy, if the exploit allows for remote code execution (RCE) in the browser or other highly-privileged process, such as network or GPU process, to result in a sandbox escape without the need of a first stage bug, the reward amount for renderer RCE “high quality report with functional exploit” would be granted and included in the calculation of the bonus reward total. Based on our current Chrome VRP reward matrix, your full chain exploit could result in a total reward of over $165,000 -$180,000 for the first full chain exploit and over $110,000 - $120,000 for subsequent full chain exploits we receive in the six month window of this reward opportunity. We’d like to thank our entire Chrome researcher community for your past and ongoing efforts and security bug submissions! You’ve truly helped us make Chrome more secure for all users. Happy Hunting!

Adding Chrome Browser Cloud Management remediation actions in Splunk using Alert Actions

May 31, 2023

Posted by Ashish Pujari, Chrome Security Team Introduction Chrome is trusted by millions of business users as a secure enterprise browser. Organizations can use Chrome Browser Cloud Management to help manage Chrome browsers more effectively. As an admin, they can use the Google Admin console to get Chrome to report critical security events to third-party service providers such as Splunk® to create custom enterprise security remediation workflows. Security remediation is the process of responding to security events that have been triggered by a system or a user. Remediation can be done manually or automatically, and it is an important part of an enterprise security program. Why is Automated Security Remediation Important? When a security event is identified, it is imperative to respond as soon as possible to prevent data exfiltration and to prevent the attacker from gaining a foothold in the enterprise. Organizations with mature security processes utilize automated remediation to improve the security posture by reducing the time it takes to respond to security events. This allows the usually over burdened Security Operations Center (SOC) teams to avoid alert fatigue. Automated Security Remediation using Chrome Browser Cloud Management and Splunk Chrome integrates with Chrome Enterprise Recommended partners such as Splunk® using Chrome Enterprise Connectors to report security events such as malware transfer, unsafe site visits, password reuse. Other supported events can be found on our support page. The Splunk integration with Chrome browser allows organizations to collect, analyze, and extract insights from security events. The extended security insights into managed browsers will enable SOC teams to perform better informed automated security remediations using Splunk® Alert Actions. Splunk Alert Actions are a great capability for automating security remediation tasks. By creating alert actions, enterprises can automate the process of identifying, prioritizing, and remediating security threats. In Splunk®, SOC teams can use alerts to monitor for and respond to specific Chrome Browser Cloud Management events. Alerts use a saved search to look for events in real time or on a schedule and can trigger an Alert Action when search results meet specific conditions as outlined in the diagram below.

Use Case If a user downloads a malicious file after bypassing a Chrome “Dangerous File” message their managed browser/managed CrOS device should be quarantined. Prerequisites

Create a Chrome Browser Cloud Management account at no additional costs

Splunk® Enterprise v9.0.* or Splunk® Cloud Platform (Cost: Please refer to Splunk’s website)

Understanding of the Splunk alerting workflow

Understanding of how to create custom alert actions in Splunk®.

Setup

Install the Google Chrome Add-on for Splunk App

Please follow installation instructions here depending on your Splunk Installation to install the Google Chrome Add-on for Splunk App.

Setting up Chrome Browser Cloud Management and Splunk Integration

Please follow the guide here to set up Chrome Browser Cloud Management and Splunk® integration.

Setting up Chrome Browser Cloud Management API access

To call the Chrome Browser Cloud Management API, use a service account properly configured in the Google admin console. Create a (or use an existing) service account and download the JSON representation of the key.

Create a (or use an existing) role in the admin console with all the “Chrome Management” privileges as shown below.

Assign the created role to the service account using the “Assign service accounts” button.

Setting up Chrome Browser Cloud Management App in Splunk®

Install the App i.e. Alert Action from our Github page. You will notice that the Splunk App uses the below directory structure. Please take some time to understand the directory structure layout.

Setting up a Quarantine OU in Chrome Browser Cloud Management

Create a “Quarantine” OU to move managed browsers into. Apply restrictive policies to this OU which will then be applied to managed browsers and managed CrOS devices that are moved to this OU. In our case we set the below policies for our “Quarantine” OU called Investigate.These policies ensure that the quarantined CrOS device/browser can only open a limited set of approved URLS.

URL Blocklist - Block access to all URLs
URL Allowlist - Allow only approved URLs for e.g. IT Helpdesk website
New Tab Page Location - Set New tab page URL to an internal website asking the user to contact IT Helpdesk.
Home Page is New Tab Page - Use the New Tab page as the user's homepage.

Configuration

Start with a search for the Chrome Browser Cloud Management events in the Google Chrome Add-on for Splunk App. For our instance we used the below search query to search for known malicious file download events.

Save the search as an alert. The alert uses the saved search to check for events. Adjust the alert type to configure how often the search runs. Use a scheduled alert to check for events on a regular basis. Use a real-time alert to monitor for events continuously. An alert does not have to trigger every time it generates search results. Set trigger conditions to manage when the alert triggers. Customize the alert settings as per enterprise security policies. For our example we used a real time alert with a per-result trigger. The setup we used is as shown below.

As seen in the screenshot we have configured the Chrome Browser Cloud Management Remediation Alert Action App with

The OU Path of the Quarantine OU i.e. /Investigate
The Customer Id of the workspace domain
Service Account Key JSON value

Test the setup

Use the testsafebrowsing website to generate sample security events to test the setup.

Open the testsafebrowsing website
Click the link for line item 4 under the Desktop Download Warnings section i.e. “Should show an "uncommon" warning, for .exe”
You will see a Dangerous Download blocked warning giving you two options to either Discard or Keep the downloaded file. Click on Keep
This will trigger the alert action and move your managed browser or managed CrOS device to the “Quarantine” OU (OU name Investigate in our example) with restricted policies.

Conclusion

Security remediation is vital to any organization’s security program. In this blog we discussed configuring automated security remediation of Chrome Browser Cloud Management security events using Splunk alert actions. This scalable approach can be used to protect a company from online security threats by detecting and quickly responding to high fidelity Chrome Browser Cloud Management security events thereby greatly reducing the time to respond.

Our team will be at the Gartner Security and Risk Management Summit in National Harbor, MD, next week. Come see us in action if you’re attending the summit.

Time to challenge yourself in the 2023 Google CTF!

May 26, 2023

Vincent Winstead, Technical Program Manager

It’s Google CTF time! Get your hacking toolbox ready and prepare your caffeine for rapid intake. The competition kicks off on June 23 2023 6:00 PM UTC and runs through June 25 2023 6:00 PM UTC. Registration is now open at g.co/ctf.

Google CTF gives you a chance to challenge your skillz, show off your hacktastic abilities, and learn some new tricks along the way. It consists of a set of computer security puzzles (or challenges) involving reverse-engineering, memory corruption, cryptography, web technologies, and more. Use obscure security knowledge to find exploits through bugs and creative misuse. With each completed challenge your team will earn points and move up through the ranks.

The top 8 teams will qualify for our Hackceler8 competition taking place in Tokyo later this year. Hackceler8 is our experimental esport-style hacking game, custom-made to mix CTF and speedrunning. In the competition, teams need to find clever ways to abuse the game features to capture flags as quickly as possible. See the 2022 highlight reel to get a sense of what it’s like. The prize pool for this year’s event stands at more than $32,000!

Screenshot from Hackeler8 2022 speedrun competition

Itching to get started early? Want to learn more, or get a leg up on the competition? Review challenges from previous years, including previous Hackceler8 matches, all open sourced on GitHub. Or gain inspiration by binge watching hours of Hackceler8 2020 videos!

If you are just starting out in this space, check out last year’s event H4CK1NG GOOGLE! It’s a great way to get acquainted with security. You can also get ready for this year’s Beginner’s Quest that’ll be launching later this summer which will be in the theme of Computer History, so get ready for some technology archaeology.

Whether you’re a seasoned CTF player or just curious about cyber security and ethical hacking, we want you to join us. Sign up to expand your skill set, meet new friends in the security community, and even watch the pros in action. For the latest announcements, see g.co/ctf, subscribe to our mailing list, or follow us on Twitter @GoogleVRP. Interested in bug hunting for Google? Check out bughunters.google.com. See you there!

Google Trust Services ACME API available to all users at no cost

May 25, 2023

David Kluge, Technical Program Manager, and Andy Warner, Product Manager

Nobody likes preventable site errors, but they happen disappointingly often.

The last thing you want your customers to see is a dreaded 'Your connection is not private' error instead of the service they expected to reach. Most certificate errors are preventable and one of the best ways to help prevent issues is by automating your certificate lifecycle using the ACME standard. Google Trust Services now offers our ACME API to all users with a Google Cloud account (referred to as “users” here), allowing them to automatically acquire and renew publicly-trusted TLS certificates for free. The ACME API has been available as a preview and over 200 million certificates have been issued already, offering the same compatibility as major Google services like google.com or youtube.com.

The Automatic Certificate Management Environment (ACME) protocol enables users to easily automate their TLS certificate lifecycle using a standards based API supported by dozens of clients to maintain certificates. ACME has become the de facto standard for certificate management on the web and has helped broaden adoption of TLS. The majority of all TLS certificates in the WebPKI today are issued by ACME CAs. ACME users experience fewer service outages caused by expired certificates by using ACME's automated certificate renewal capabilities. Manual certificate updates are a common source of outages, even for major online services. Sites already using ACME can configure multiple ACME providers to increase resilience during CA outages or mass renewal events.

What customers say

During the preview phase, the ACME endpoint has already been used extensively. The number of certificates requested by our users has driven up the GTS issuance volume to the fourth largest publicly trusted Certificate Authority.

"At Cloudflare, we believe encryption should be free for all; we pioneered that for all our customers back in 2014 when we included encryption for free in all our products. We're glad to see Google join the ranks of certificate authorities that believe encryption should be free for everyone, and we're proud to offer Google as a CA choice for our customers. Their technical expertise guarantees they'll be able to scale to meet the needs of an increasingly encrypted Internet," says Matthew Prince, CEO, Cloudflare.

Making the Web Safer

The Google Trust Services ACME API was introduced last year as a preview. The service recently expanded support for Google Domains customers. By further opening up the service, we're adding another tool to Google’s Cyber Security Advancements, keeping individuals, businesses, and governments safer online through highly trusted and free certificates. We're also introducing two significant features that further enhance the certificate ecosystem: ACME Renewal Information (ARI) and Multi-perspective Domain Validation. ARI is a new standard to help manage renewals that we're excited to support. General availability of multi-perspective domain validation brings the benefits of years of work to increase the security of Google's certificates for all users.

ACME Renewal Information (ARI)

ACME Renewal Information (ARI) addresses the longstanding challenge of knowing when a certificate must be replaced before its standard renewal period via an API.

ARI is an Internet Engineering Task Force (IETF) Internet Draft authored by Let’s Encrypt as an extension to the ACME protocol. It helps service operators automatically replace their certificates in case revocation must occur before the certificate expires.

Serving certificate renewal information via ACME is particularly useful for managing large certificate populations. ARI could have potentially made a difference in past certificate replacement events affecting large parts of the WebPKI, including the 2019 serial number entropy bug affecting multiple CAs which forced rapid replacement of hundreds of thousands of certificates.

Multi-Perspective Domain Validation

Multi-perspective domain validation (MPDV), enhances the validation process for certificate issuance. Publicly-trusted CAs, like Google Trust Services, ensure only authorized requesters can obtain certificates for a given domain name by confirming the requester can prove control over the domain via validation challenges. Domain validation provides a high level of assurance under normal conditions. However, domain control validation methods can be vulnerable to attacks such as DNS cache poisoning and Border Gateway Protocol (BGP) hijacking.

With MPDV, domain control verification is performed from multiple locations, referred to as “network perspectives.” Using multiple perspectives significantly improves the reliability of validation by preventing localized attacks from being able to fool validation checks. Let’s Encrypt adopted the first at-scale MPDV implementation, which performed the validation from three different network perspectives and required a quorum before issuance.

Our approach is similar. We also require a quorum of different network perspectives, but thanks to the scale and reach of our infrastructure, we have thousands of egress points forming “regional perspectives” that deter attackers from compromising enough targets to secure an invalid validation.

How do I use it?

Please see the Public CA Tutorial. The ACME API is free and available to anyone with a Google Cloud account. More information is available at pki.goog.