ewon_cosy_firmware: Direct Request
CVE-2024-33897 is a critical-severity direct request vulnerability in ewon_cosy_firmware from HMS Networks, 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. The record lists versions 21.2s10, 22.1s3 as the first without the flaw, so updating ewon_cosy_firmware to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.66% chance of exploitation within 30 days, higher than 52% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update ewon_cosy_firmware to 21.2s10 or 22.1s3, whichever matches your release line, or a later version.
- Read the advisory on hmsnetworks.blob.core.windows.net 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 |
|---|---|---|---|
| Hms-networks | ewon_cosy_firmware | 21.0 up to, but not including, 21.2s10; 22.0 up to, but not including, 22.1s3 | 21.2s10, 22.1s3 |
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
- NoneNo data is disclosed.
- 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:N/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.1 | Critical | NVD |
| CVSS 3.1 | 9.1 | Critical | CISA (ADP) |
Official description
A compromised HMS Networks Cosy+ device could be used to request a Certificate Signing Request from Talk2m for another device, resulting in an availability issue. The issue was patched on the Talk2m production server on April 18, 2024.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Direct Request
The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.
How developers prevent this class of flaw
- Apply appropriate access control authorizations for each access to all restricted URLs, scripts or files.
- Consider using MVC based frameworks such as Struts.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- blog.syss.com/posts/hacking-a-secure-industrial-remote-access-gateway/Exploit, Third Party Advisory
Other references
Other vulnerabilities in ewon_cosy_firmware
- 7.2 High severity
- 8.8 High severity
- 7.5 High severity
Recent Direct Request vulnerabilities
- 7.3 High severity
- 7.3 High severity
- 7.5 High severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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