Ghost: Unrestricted Upload of File with Dangerous Type
CVE-2022-28397 is a critical-severity unrestricted upload of file with dangerous type vulnerability in Ghost, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Ghost versions: 4.42.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 3.5% chance of exploitation within 30 days, higher than 89% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Ghost you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. 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
- HighData or code can be modified at will.
- 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:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 2.0 | 7.5 | High | NVD |
Official description
An arbitrary file upload vulnerability in the file upload module of Ghost CMS v4.42.0 allows attackers to execute arbitrary code via a crafted file. NOTE: Vendor states as detailed in Ghost's security documentation, files can only be uploaded and published by trusted users, this is intentional.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Unrestricted Upload of File with Dangerous Type
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
How developers prevent this class of flaw
- Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
More Unrestricted Upload of File with Dangerous Type vulnerabilities (CWE-434)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- github.com/TryGhost/GhostThird Party Advisory
Technical write-ups (may include proof of concept)
- youtu.be/PncfBetPk2gExploit, Third Party Advisory
Other references
Other vulnerabilities in Ghost
- 9.1 Critical severity
- 9.0 Critical severity
- 7.5 High severity
- 9.8 Critical severity
Recent Unrestricted Upload of File with Dangerous Type vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
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