TN-5900 Series: Improper Neutralization of Special Elements used in a Command
CVE-2023-33239 is a critical-severity improper neutralization of special elements used in a command vulnerability in TN-5900 Series from Moxa, 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 TN-5900 Series versions: 1.0 through 3.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.32% chance of exploitation within 30 days, higher than 71% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of TN-5900 Series you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on moxa.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 |
|---|---|---|---|
| Moxa | TN-5900 Series | 1.0 through 3.3 | Not stated |
| Moxa | TN-4900 Series | 1.0 through 1.2.4 | Not stated |
| Moxa | EDR-810 Series | 1.0 through 5.12.27 | Not stated |
| Moxa | EDR-G902 Series | 1.0 through 5.7.17 | Not stated |
| Moxa | EDR-G903 Series | 1.0 through 5.7.15 | Not stated |
| Moxa | EDR-G9010 Series | 1.0 through 2.1 | Not stated |
| Moxa | NAT-102 Series | 1.0 through 1.0.3 | Not stated |
| Moxa | edr-g903 | 1.0 through 5.7.15 | Not stated |
| Moxa | tn-5900 | 1.0 through 3.3 | Not stated |
| Moxa | tn-4900 | 1.0 through 1.2.4 | Not stated |
| Moxa | edr-810 | 1.0 through 5.12.27 | Not stated |
| Moxa | edr-g902 | 1.0 through 5.7.17 | Not stated |
| Moxa | edr-g9010 | 1.0 through 2.1 | Not stated |
| Moxa | nat-102 | 1.0 through 1.0.3 | Not stated |
| Moxa | Tn-5900 Firmware | 3.3 and earlier | Not stated |
| Moxa | Tn-4900 Firmware | 1.2.4 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
- 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 | 8.8 | High | CNA (moxa.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
TN-4900 Series firmware versions v1.2.4 and prior and TN-5900 Series firmware versions v3.3 and prior are vulnerable to the command injection vulnerability. This vulnerability stems from insufficient input validation in the key-generation function, which could potentially allow malicious users to execute remote code on affected devices.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in a Command
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- If possible, ensure that all external commands called from the program are statically created.
- Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
More Improper Neutralization of Special Elements used in a Command vulnerabilities (CWE-77)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in TN-5900 Series
- 8.1 High severity
- 8.1 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Improper Neutralization of Special Elements used in a Command vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.2 High severity
- 9.8 Critical severity
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