Joomla versions 2.4.0 and below suffer from a cross site scripting vulnerability in the Gridbox extension.
a67e61410dc53b192fa83ce0ba67d2d0I. VULNERABILITY
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Gridbox extension for Joomla! <= 2.4.0 Reflected Cross Site Scripting (XSS)
II. CVE REFERENCE
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CVE-2018-11690
III. VENDOR
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https://extensions.joomla.org/extension/gridbox/
IV. REFERENCES
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https://vulmon.com/vulnerabilitydetails?qid=CVE-2018-11690
https://vel.joomla.org/resolved/2155-gridbox-com-gridbox-multiple-vulnerabilities
V. TIMELINE
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02/04/2018 Vulnerability discovered
09/04/2018 Vendor contacted
23/04/2018 Vulnerability fixed
VI. CREDIT
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Yavuz Atlas of Biznet Bilisim
http://www.biznet.com.tr/biznet-guvenlik-duyurulari
VII. DESCRIPTION
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Balbooa Gridbox extension version 2.4.0 and previous versions for
Joomla! is vulnerable to cross-site scripting. A remote attacker could
exploit this vulnerability via a crafted URL to execute script in a
victim's Web browser within the security context of the hosting Web
site, once the URL is clicked. An attacker could use this
vulnerability to steal the victim's cookie-based authentication
credentials
VIII. PROOF OF CONCEPT
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For category parameter:
http://localhost:81/bg/Joomla_3.8.5-Stable-Full_Package/index.php?option=com_gridbox&view=pages&app=aaa&category=<script>alert(1)</script>
For app parameter:
http://localhost:81/bg/Joomla_3.8.5-Stable-Full_Package/index.php?option=com_gridbox&view=pages&app=<script>alert(1)</script>&category=aaa