Crimson: Improper Neutralization of Null Byte or NUL Character
CVE-2023-5719 is a critical-severity improper neutralization of null byte or NUL character vulnerability in Crimson from Red Lion, 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 Crimson versions: v3.2.0053.18 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 Crimson you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on support.redlion.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
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 (hq.dhs.gov) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
The Crimson 3.2 Windows-based configuration tool allows users with administrative access to define new passwords for users and to download the resulting security configuration to a device. If such a password contains the percent (%) character, invalid values will be included, potentially truncating the string if a NUL is encountered. If the simplified password is not detected by the administrator, the device might be left in a vulnerable state as a result of more-easily compromised credentials. Note that passwords entered via the Crimson system web server do not suffer from this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Null Byte or NUL Character
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.
How developers prevent this class of flaw
- Developers should anticipate that null characters or null bytes will be injected/removed/manipulated in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More Improper Neutralization of Null Byte or NUL Character vulnerabilities (CWE-158)
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
Third-party and government advisories
- cisa.gov/news-events/ics-advisories/icsa-23-306-01Third Party Advisory, US Government Resource
Recent Improper Neutralization of Null Byte or NUL Character vulnerabilities
- 9.3 High severity
Microsoft DirectX NULL Byte Overwrite Exploited
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