Joomla! Component Acymailing Starter 5.9.5 - CSV Macro Injection

# Exploit Title: Joomla! Component Acymailing Starter 5.9.5 CSV Macro
Injection
# Google Dork: N/A
# Date: 22-03-2018
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# Exploit Author: Sureshbabu Narvaneni
################################
# Vendor Homepage: https://www.acyba.com
# Software Link: https://extensions.joomla.org/extension/acymailing-starter/
# Affected Version: 5.9.5
#Category: WebApps
# Tested on: Ubuntu 14.04 x86_64/Kali Linux 4.12 i686
# CVE : CVE-2018-9107

1. Vendor Description:

AcyMailing is a reliable Newsletter and email marketing extension for
Joomla.
It enables you to efficiently manage an unlimited number of subscribers,
organize them into mailing lists, send personalized newsletters (Hi
{name}...)

2. Technical Description:

CSV Injection (aka Excel Macro Injection or Formula Injection) exists in
the export feature in the Acyba AcyMailing extension before 5.9.6 for
Joomla! via a value that is mishandled in a CSV export.

3. Proof Of Concept:

Login as low privileged user who is having access to Acymailing Component.
Rename user name as @SUM(1+1)*cmd|' /C calc'!A0.

When high privileged user logged in and exported user data then the CSV
Formula gets executed and calculator will get popped in his machine.

4. Solution:

Upgrade to version 5.9.6
https://extensions.joomla.org/extension/acymailing-starter/

5. Reference:
https://github.com/MrR3boot/CVE-Hunting/blob/master/AcyStarter-CSV.mp4
https://vel.joomla.org/articles/2140-introducing-csv-injection

Sureshbabu Narvaneni,
Security Analyst | Bug Hunter,
HackerOne (mrreboot/mrr3boot) | BugCrowd (Mr_R3boot)