MyScript Memo 3.0 Persistent Script Insertion

2016-02-11T00:00:00
ID PACKETSTORM:135718
Type packetstorm
Reporter Benjamin Kunz Mejri
Modified 2016-02-11T00:00:00

Description

                                        
                                            `Document Title:  
===============  
MyScript Memo v3.0 iOS - (Mail) Persistent Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1706  
  
  
Release Date:  
=============  
2016-02-10  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1706  
  
  
Common Vulnerability Scoring System:  
====================================  
3.6  
  
  
Product & Service Introduction:  
===============================  
With MyScript Memo, take your notes on the go using your handwriting and convert them to digital text that you   
can export and share with Evernote®, Facebook®, Twitter®, Gmail or copy/paste to any other text application.   
MyScript Memo is available in 63 recognition languages (including Chinese, Korean, Japanese, Arabic, Russian,   
English, Spanish, French and many more).   
  
(Copy of the Homepage: https://itunes.apple.com/us/app/myscript-memo/id446368116 )  
  
  
Abstract Advisory Information:  
==============================  
The Vulnerability Laboratory Core Research Team discovered a persistent mail encoding web vulnerability in the official MyScript Memo iOS mobile web-application.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2016-02-10: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
MyScript  
Product: MyScript Memo - iOS (Web-Application) 3.0.0.363  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
Medium  
  
  
Technical Details & Description:  
================================  
A persistent mail encoding and file extension validation vulnerability has been discovered in the official MyScript Memo v3.0.0 iOS mobile web-application.  
The vulnerability allows an remote attacker or local privileged user account to inject own malicious script codes to the application-side of the affected modules.  
  
The issue is located in the notes-filename and document text context of the export module. Local low privileged web-application user accounts are able to inject   
own malicious persistent script codes to the mail body context of the `share` function. Attacker can manipulate the notes files as extension or the main document   
context to send malicious mails with persistent injected script codes. The request method to inject is POST and the attack vector of the issue is located on the   
application-side of the iOS mobile web-application.  
  
The security risk of the application-side input web vulnerability is estimated as medium with a cvss (common vulnerability scoring system) count of 3.6.   
Exploitation of the persistent web vulnerability requires a low privileged ios device account with restricted access and low or medium user interaction.   
Successful exploitation of the vulnerability results in persistent phishing mails, session hijacking, persistent external redirect to malicious   
sources and application-side manipulation of affected or connected module context.  
  
Vulnerable Module(s)  
[+] Export  
  
Vulnerable File(s)  
[+] *.notes  
  
Affected Module(s)  
[+] Email  
  
  
Proof of Concept (PoC):  
=======================  
The vulnerability can be exploited by remote attackers and local low privileged user accounts with low or medium user interaction.  
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.  
  
  
Manual steps to reproduce the vulnerability ...  
1. Install the mobile web-application  
2. Start the mobile web-application  
3. Add a new `Notizen` item via (+)  
4. Use now a payload (script codes) as notiz name  
5. Save the entry and open the document  
6. Write with your finger a script code payload in the document and save it  
7. Click (top|left) the export function  
8. Use the function `As MyScript-File`  
9. Now click the email button  
Note: The file generates a notes file with the malicious payload for import/export. It also uses the file input payload of the document.  
10. Successful reproduce of the persistent mail encoding web vulnerability and notes file validation issue!  
  
  
PoC: Source  
<html>  
<head>  
<title>memo script app ios</title>  
<link rel="important stylesheet" href="chrome://messagebody/skin/messageBody.css">  
</head>  
<body><table border=0 cellspacing=0 cellpadding=0 width="100%" class="header-part1"><tr><td><b>Betreff: </b>memo script app ios</td></tr>  
<tr><td><b>Von: </b>Benjamin Mejri Kunz <vulnlabstars@icloud.com></td></tr><tr><td><b>Datum: </b>31.01.2016 14:08</td></tr></table>  
<table border=0 cellspacing=0 cellpadding=0 width="100%" class="header-part2"><tr><td><b>An: </b>bkm@evolution-sec.com</td></tr></table><br>  
<div class="moz-text-plain"><pre wrap>  
Angehängt: ">"<[PERSISTENT INJECTED SCRIPT CODE VIA MEMO!]  
</pre></div><BR><FIELDSET CLASS="mimeAttachmentHeader"></FIELDSET><BR/><div class="moz-text-plain"><pre wrap>  
Von meinem iPad gesendet</pre></div></body>  
</html>  
  
  
  
PoC: poc.notes  
v3.0  
VO_INK_DOCUMENT  
1180  
Ò 3   
«Wq€ šüX·QÃ2† ÃA˜ŒÌŒ##fI´•]\åqN~wWU¾Ê± ˆÌ†!ŒF#6Ñ2l™2bF&fDi“$šM„a  
m(CÅî… ’<µahWyÒrœ«H,®î¡ËB 0€«Wr€ šüÊ¢vY”‘2m$FC(ã  
s»¢—5‚٠€J€«Wr€ šüfÅ8ìÈÿþ,Cçp‚ŠS++颢8-ž  
&`5«Ws€ šü  
FQ‹2©\â”(§8§r•ïòI$Ä ƒa„‚“$]„c1b™"dÙ2hˆÄa„!ÌͲHxÈðXpg]Õ-[Z8  
í(B„ Üï™ÖÔµR¾!îBÀ ˆ«Wt šüê5ELÈ C' üÚœQ„qŽBÈêì‚jBçMó‚[ ›¡‚êìºÛ@€«Wu šü  
Ô2c™'·1Î Æ#ªøTс¬üT!8«Wu€ šü–ô–Ve  
8pàPPãŽw‹'–I3ÌC„bh¤–;BœY‡(hà¢ÅŠ$P‘'œ AÆšYd÷µŠJ«À@aØf„ç™Ï¤!jÚ4´ëŒBÒÕ1  
qÈ @«Wv šü+ NlÌ,8Y†KV• æžIw3_´ÔM†× ¬/«Wv€ šü6¾¡Ve±ÄAVwTeeDDB(ƒr;¦ÚYÇ4ÃŒ,–¹iQ[.T™ÿÜ΄(î‘¢µ¼„ä÷iÂSr‘Ç– : *«Ww šü<ZQ«2Ú¶¼KÍ,ÒÚ¿˜ŠC(ã…æuVDDD!Ž(Á9™ÙÖ…1äI§œ AÆ–÷-A7Í›.U•{›ÇËiÂDQZP5;¦§ãyò¹ÅgªK¬+[ÅYj  
Yd ѵѕo$±¥ À«Wx šüü®P³2éLs†#«+¹ ¢  
‚†r²¢#fâ10Â!Ž!HUTDNÌL4ñ"Ä ,¦-H&\ø™òëöp¢Ëiç AOXéóåßm[ÎâŠ$ÃEˆq¤1I0<Íc*%§½Ë  
—ííÅ’ä0ÝS¸N–£4ÎB8j˜†JW?¶T²@0€«Wx€ šüÒ£æf(ðAK-ÉAv]t©vÛ_©§»Ö`‘B†„Œ<âZnˆ…¯Ö÷’{S10pÀ` `ƒ  
QNrYY @¤šÌO˜~W ÁåpÆ=„þr¾Òõ l«Wy€ šü=,&f)  
kÞiEòˆ!伂æ©)_)ºD™räÈ“UÎ9ï ³8ñad÷9ÎbЕ%Ži%”YµÉBÀPwýƒ:œy\Q+âô,ÒUVì¯[ÞRÄÜà LÀ  
VO_DOCUMENT  
317  
<Document version="1.0"><DateCreated>2016-01-31T14:06:40</DateCreated><DateModified>2016-01-31T14:06:59</DateModified><Height>263.200012</Height><Width>210.000000</Width><PredefinePaper>horizontalLinePaper</PredefinePaper><LinePatternUnit>13.210000</LinePatternUnit><PrimaryLanguage>en_US</PrimaryLanguage></Document>  
D938BA68-4505-47CB-BFEE-DADC1E5ED150  
79  
<Page version="1.0"><PredefinePaper>horizontalLinePaper</PredefinePaper></Page>  
VO_DOCUMENT_STRUCTURE  
128  
<Document version="1.0"><Pages><Page id="D938BA68-4505-47CB-BFEE-DADC1E5ED150"><PageItems></PageItems></Page></Pages></Document>  
  
  
Solution - Fix & Patch:  
=======================  
The vulnerability can be patched by a secure parse and encode of the filename variable and the document input text context.  
Restrict the input and disallow special chars.  
Encode the mail context input next to the attachment. Disallow note files with specialchars to prevent a malicious import/export.  
Filter the filename validation to approve for malicious context and to prevent further script code injection attacks.  
  
  
Security Risk:  
==============  
The security risk of the persistent mail encoding web vulnerability in the notes file extension and mail is estimated as medium. (CVSS 3.6)  
  
  
Credits & Authors:  
==================  
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (research@vulnerability-lab.com) [www.vulnerability-lab.com]  
  
  
Disclaimer & Information:  
=========================  
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