Brave Software: RCE: DnDing shortcut files to chrome://brave allows loading HTML files in Muon's context

Summary: \395737 has shown that Brave supports chrome://brave/ URLs. The Brave team introduced a patch which blocks navigation to chrome://brave and removed chrome.remote.require to prevent command execution on the machine. Navigation to chrome://brave via shortcut files From my understanding: 1...

Brave Software: chrome://brave can still be navigated to, leading to RCE

Summary: 'chrome://brave' can be navigated to using the middle mouse click or normal click with CTRL held IFF coming from a bookmark. I am also using a small bug to actually trick a user into bookmarking our crafted URL through drag and drop. Products affected: Brave: 0.24.0 V8: 6.9.427.23 rev:...

Brave Software: `chrome://brave` available for navigation in Release build [-> RCE] + navigation to `chrome://*` using tab_helper ["Open in new tab"]

Summary: chrome://brave is available for navigation Navigation to chrome://brave + requires local file at . The file loaded in this context has access to private Muon APIs such as chrome.ipcRenderer/remote/webFrame/webViewRequest. Muon API allows executing code on the device. e.g. with...

Brave Software: Local files reading from the "file://" origin through `brave://`

Summary: Sadly, fix for 390013 works only for web. Loading brave:// from the file:// origin allows reading local files on the device. I said that fix could be insufficient 😈 file:// and brave:// both are local origins. That means it's possible to access brave:// from file:// and vice versa...

Brave Software: Local files reading from the web using `brave://`

Summary: brave:// protocol was introduced as a replacement for AsarProtocolHandleror something like that in brave/muon after 375329. However, fix for 375329 introduced a new much severe bug that allows reading files from a user's device from the web. PoC is similar to 375329, but it uses brave://...

brave-answer.jp XSS vulnerability

Open Bug Bounty ID: OBB-649325 Description| Value ---|--- Affected Website:| brave-answer.jp Open Bug Bounty Program:| Create your bounty program now. It's open and free. Vulnerable Application:| Custom Code Vulnerability Type:| XSS Cross Site Scripting / CWE-79 CVSSv3 Score:| 6.1...

Brave Software: Torrent extension: Cross-origin downloading + "URL spoofing" + CSP-blocked XSS

Summary: \378809 allows navigating to chrome-extension:// \378805 allows displaying alert windows on chrome-extension:// origin As I said in 378809, navigation to chrome-extension:// allows attacking dependencies/components of extensions. Brave has only 3 extensions installed by default w\o...

Brave Software: `alert()` dialogs on `chrome-extension://` origin (internal pages)

Summary: Navigation to chrome-extension from the web is possible with 378805 ftp:// - chrome-extension://. A blank page is created during navigation to chrome-extension:// origin. Blank pages have "This page" title. It's possible to initiate alert with a social-engineering content and "This page"...

Brave Software: Navigation to `chrome-extension://` origin (internal pages) from the web

Summary http and https pages are disallowed from navigating to chrome-extension:// origin. However, ftp protocol isn't checked. Pages from ftp:/// and file:/// origin could navigate to chrome-extension:// origin. Steps to reproduce: 1. Start ftp server sample ftp server attached, npm i ftpd && no...

Brave Software: `settingcontent-ms` files lacks "mark of the web" => execute code by dbl click in Downloads toolbar

Summary: settingcontent-ms files allow launching any binary with any params. Brave doesn't mark settingcontent-ms files with "mark of the web", so the file could be executed by double click in "Downloads" toolbar. Launched settingcontent-ms file could lead to code execution with user-level...

A week in security (June 25 – July 1)

Last week on Labs, we looked at comment moderation duties, Viagra spam on a news-making restaurant's website, and how to manage your child's online presence for Internet safety month. We also looked at a set of big breaches and leaks, as well as malware threats with a World Cup vibe. Other news...

Brave Software: Local files reading using `link[rel="import"]`

Summary: HTML file could import another file using . Brave returns Access-Control-Allow-Origin: response header for local HTML files. That leads to local files reading. This vulnerability makes 369218 critical. Products affected: Brave: 0.23.19 V8: 6.7.288.46 rev:...

Brave Software: Cross-origin page stays focused before/after downloading + uninformative modal window for download

Summary: 1. Open twitter.com using window.open 2. Wait some time to finish page rendering 3. Change location of the opened page to any downloading 4. Download modal appears above the twitter.com The problem is that a user doesn't see what page exactly initiates downloading and what resourceURL wi...

Brave Software: Navigation to protocol handler URL from the opened page displayed as a request from this page.

Summary: Navigation to protocol handler URL from the page opened using window.open is considered as a request from the opened page. Example: 1. The page opens google.com 2. The page changes opened window's location to ssh://evil.com 3. Request to open ssh://evil.com URL displayed at google.com...

Brave Software: Lack of quarantine meta-attribute for downloaded files leads to GateKeeper bypass

Summary: Executable files downloaded through Brave don't have quarantine attribute. That means it's possible to launch any executable bypassing codesigning + quarantine. However, later I found that Brave has already tracked similar report but only in the context of .pkg files. Additionally, Brave...

Brave Software: URL spoofing using protocol handlers

Summary: Navigation to protocol handler changes URL in the address bar e.g. ssh://google.com in the address bar is standard behavior. Browsers change URL in the address bar to about:blank if a parent window tries to access the opened page with protocol handler URL. This behavior prevents URL...

Brave Software: Directory Listing on https://promo-services-staging.brave.com

Summary: Hi Brave team, Hope you are good I have found a directory listing vulnerability at https://promo-services-staging.brave.com Products affected: Brave website page. Steps To Reproduce: Go to https://promo-services-staging.brave.com/swaggerui/ Supporting Material/References: Reference: This...

Brave Software: OPEN REDIRECTION at every 302 HTTP CODE

Summary i guess every 302 HTTP CODE on https://publishers.basicattentiontoken.org possible to OpenRedirection Steps To Reproduce: 1. I edited the request when i got redirected from this request url...

Brave Software: Navigation to restricted origins via "Open in new tab"

Summary: It's possible to open links pointing to file:/// origin from web pages using "Open link in a new tab" in context menu. https://hackerone.com/bugs?reportid=369185 shows unsafe ssh:// protocol handling, which leads to information leak using sshOS username and etc.. The vulnerability is...

Brave Software: Unsafe handling of protocol handlers

Summary: Brave browser macOS handles protocol handlers in unsafe way and differently from other browsers. Key differences between protocol handlers handling in Brave and other browsers: Open external app vs Open "Terminal" Brave only asks about opening external app. Other browsers e.g. Chrome ask...