Kurz gesagt
- CVE-2023-40033 ist eine Schwachstelle (HOCH (CVSS 7.1)) in flarum/core, flarum/framework, flarum (flarum).
- Wahrscheinlichkeit einer Ausnutzung in den nächsten 30 Tagen (EPSS): 0.50%, höher als bei 43.1% aller Schwachstellen.
- Abhilfe: auf 1.8.0 oder neuer aktualisieren.
Description
Impact
The Flarum forum software is affected by a vulnerability that allows an attacker to conduct a Blind SSRF attack or disclose any file on the server, even with a basic user account on any Flarum forum. By uploading a file containing a URL and spoofing the MIME type, an attacker can manipulate the application to execute unintended actions. The vulnerability is due to the behavior of the intervention/image package, which attempts to interpret the supplied file contents as a URL, which then fetches its contents. This allows an attacker to exploit the vulnerability to perform SSRF attacks, disclose local file contents, or conduct a blind oracle attack.
Patches
This has been patched in Flarum v1.8.
Workarounds
As a temporary workaround for the SSRF aspect of the vulnerability, one can disable PHP's allow_url_fopen which will prevent the fetching of external files via URLs.
Credits
Adam Kues - Assetnote
NVD description
Flarum is an open source forum software. Flarum is affected by a vulnerability that allows an attacker to conduct a Blind Server-Side Request Forgery (SSRF) attack or disclose any file on the server, even with a basic user account on any Flarum forum. By uploading a file containing a URL and spoofing the MIME type, an attacker can manipulate the application to execute unintended actions. The vulnerability is due to the behavior of the `intervention/image` package, which attempts to interpret the supplied file contents as a URL, which then fetches its contents. This allows an attacker to exploit the vulnerability to perform SSRF attacks, disclose local file contents, or conduct a blind oracle attack. This has been patched in Flarum version 1.8.0. Users are advised to upgrade. Users unable to upgrade may disable PHP's `allow_url_fopen` which will prevent the fetching of external files via URLs as a temporary workaround for the SSRF aspect of the vulnerability.
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