Joomla: arbitrary file upload
Joomla
Arbitrary file upload in the Joomla component. Threat level: Critical (CVSS 9.4).
Who is affected
This vulnerability affects: Joomla. If you use this component on your site, check the version and update it as soon as possible.
How dangerous
Rating: Critical, CVSS 9.4 out of 10. Critical flaws are often exploited en masse within hours of disclosure.
What this flaw is
Arbitrary file upload lets an attacker place their own file on the server, most often a PHP script (a web shell) that gives them remote control of the site.
It is a short path from a single flaw to a full site takeover and persistent, hidden access.
Score breakdown (CVSS vector)
What the CVSS 9.4 rating means in practice:
- The attack can be carried out remotely, over the internet.
- Requires an account with elevated privileges.
- Requires no action from the victim.
Weakness class: CWE-434.
What to do
- Update the vulnerable component (Joomla) to the latest version.
- If a patch is not out yet, temporarily disable the vulnerable element.
- Check whether the site has already been attacked: unusual files, new administrator accounts, redirects.
- Make a backup before you start making changes.
Does this flaw affect your site?
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