LibreY: Server-Side Request Forgery
CVE-2023-41054 is a critical-severity server-side request forgery vulnerability in LibreY from Ahwxorg, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected LibreY versions: < 8f9b9803f231e2954e5b49987a532d28fe50a627. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.95% chance of exploitation within 30 days, higher than 62% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of LibreY you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Ahwxorg | LibreY | < 8f9b9803f231e2954e5b49987a532d28fe50a627 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.2 | High | CNA (github.com) |
| CVSS 3.1 | 9.1 | Critical | NVD |
Official description
LibreY is a fork of LibreX, a framework-less and javascript-free privacy respecting meta search engine. LibreY is subject to a Server-Side Request Forgery (SSRF) vulnerability in the `image_proxy.php` file of LibreY before commit 8f9b9803f231e2954e5b49987a532d28fe50a627. This vulnerability allows remote attackers to use the server as a proxy to send HTTP GET requests to arbitrary targets and retrieve information in the internal network or conduct Denial-of-Service (DoS) attacks via the `url` parameter. Remote attackers can use the server as a proxy to send HTTP GET requests and retrieve information in the internal network. Remote attackers can also request the server to download large files or chain requests among multiple instances to reduce the performance of the server or even deny access from legitimate users. This issue has been addressed in https://github.com/Ahwxorg/LibreY/pull/31. LibreY hosters are advised to use the latest commit. There are no known workarounds for this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Server-Side Request Forgery
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.
How developers prevent this class of flaw
- If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
- If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other vulnerabilities in LibreY
- 7.5 High severity
Recent Server-Side Request Forgery vulnerabilities
- 7.5 High severity
- 7.1 High severity
- 7.1 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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