WS-2023-0184

Date: June 22, 2023

Brave iOS has three weaknesses. By combining them, Universal XSS can be achieved. First issue - Exposure of UserScriptManager.securityToken Playlist.js embeds the exact value of the $<notifyNode> into HTMLVideoElement.prototype.setAttribute. By reading the value, an attacker can retrieve the hidden security token. Second issue - Exposure of UserScriptManager.messageHandlerToken Also, WindowRenderHelper.js embeds the exact value of the $<handler> into W{securityToken}.postMessage. By reading the value, an attacker can retrieve the hidden message handler token. Third issue - UXSS in PlaylistHelper through nodeTag PlaylistHelper.swift concatenates strings to build a JavaScript code and executes it on the mainframe of a WebView. Then, nodeTag given from a webpage is directly included in the code. So, if the nodeTag, named as tagId in JS world, passed from the page contained ');alert(document.location);//, unintended alert() is executed on the mainframe.

Language: Swift