Nextcloud Mail DoS/Proxy Abuse before 3.3.0 via Missing Origin
CVE-2023-45660 Published on October 16, 2023
Require strict cookies for image proxy requests in Nextcloud Mail
Nextcloud mail is an email app for the Nextcloud home server platform. In affected versions a missing check of origin, target and cookies allows for an attacker to abuse the proxy endpoint to denial of service a third server. It is recommended that the Nextcloud Mail is upgraded to 2.2.8 or 3.3.0. There are no known workarounds for this vulnerability.
Vulnerability Analysis
CVE-2023-45660 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2023-45660 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2023-45660
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Affected Versions
nextcloud security-advisories:- Version >= 2.0.0, < 2.2.8 is affected.
- Version >= 3.0.0, < 3.3.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.