Remote Access Server (RAS): Unrestricted Upload of File with Dangerous Type
CVE-2022-40981 is a critical-severity unrestricted upload of file with dangerous type vulnerability in Remote Access Server (RAS) from ETIC Telecom, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Remote Access Server (RAS) versions: 4.5.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.62% chance of exploitation within 30 days, higher than 50% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Remote Access Server (RAS) 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
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| ETIC Telecom | Remote Access Server (RAS) | 4.5.0 and earlier | Not stated |
| Etictelecom | Remote Access Server Firmware | 4.5.0 and earlier | 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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.9 | Medium | CNA (hq.dhs.gov) |
| CVSS 3.1 | 10.0 | Critical | NVD |
Official description
All versions of ETIC Telecom Remote Access Server (RAS) 4.5.0 and prior is vulnerable to malicious file upload. An attacker could take advantage of this to store malicious files on the server, which could override sensitive and useful existing files on the filesystem, fill the hard disk to full capacity, or compromise the affected device or computers with administrator level privileges connected to the affected device.
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
Patches and release notes
- cisa.gov/uscert/ics/advisories/icsa-22-307-01Third Party Advisory, US Government Resource
Other vulnerabilities in Remote Access Server (RAS)
- 8.6 High severity
- 7.4 High severity
- 8.1 High severity
- 7.5 High severity
- 10.0 Critical severity
Recent Unrestricted Upload of File with Dangerous Type vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
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