GHSA-mf74-qq7w-6j7v Zmarkdown Server-Side Request Forgery (SSRF) in remark-download-images
An attacker can exploit loose URL filtering to access private network resources via Server-Side Request Forgery in the remark-download-images library.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is GHSA-mf74-qq7w-6j7v?
GHSA-mf74-qq7w-6j7v is a server-side request forgery vulnerability in remark-images-download, published on 3 Feb 2024. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Impact
A major blind SSRF has been found in remark-images-download, which allowed
for requests to be made to neighboring servers on local IP ranges.
The issue came from a loose filtering of URLs inside the module.
Imagine a server running on a private network 192.168.1.0/24.
A private service serving images is running on 192.168.1.2, and
is not expected to be accessed by users. A machine is running
remark-images-download on the neighboring 192.168.1.3 host.
An user enters the following Markdown:
The image is downloaded by the server and included inside the resulting document. Hence, the user has access to the private image.
It has been corrected by preventing images downloads from local IP ranges, both in IPv4 and IPv6. To avoid malicious domain names, resolved local IPs from are also forbidden inside the module. This vulnerability impact is moderate, as it is can allow access to unexposed documents on the local network, and is very easy to exploit.
Patches
The vulnerability has been patched in version 3.1.0. If impacted, you should update to this version as soon as possible.
Please note that a minor version has been released instead of a bugfix. This is due to a new option included to prevent another vulnerability, upgrading to the new version will not break compatibility.
Workarounds
No workaround is known, the package should be upgraded.
For more information
If you have any questions or comments about this advisory, open an issue in ZMarkdown.
Which versions are affected by GHSA-mf74-qq7w-6j7v?
2 open source packages ship an affected version, including remark-images-download.
| Package | Affected | Fixed in |
|---|---|---|
remark-images-download npm | All versions | 3.1.0 |
remark-images-download npm | All versions | 3.1.0 |
How do I fix GHSA-mf74-qq7w-6j7v?
Upgrade remark-images-download to 3.1.0 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is GHSA-mf74-qq7w-6j7v being exploited?
There is no known exploitation of GHSA-mf74-qq7w-6j7v in the wild and no public exploit code.