Kasago IPv6/v4 Dual: Use of Insufficiently Random Values
CVE-2022-43501 is a critical-severity use of insufficiently random values vulnerability in Kasago IPv6/v4 Dual from ZUKEN Elmic, 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. Affected Kasago IPv6/v4 Dual versions: prior to Ver6.0.1.34. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Kasago IPv6/v4 Dual you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on elwsc.co.jp 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 |
|---|---|---|---|
| ZUKEN Elmic | Kasago IPv6/v4 Dual | prior to Ver6.0.1.34 | Not stated |
| ZUKEN Elmic | Kasago IPv4 | prior to Ver6.0.1.34 | Not stated |
| ZUKEN Elmic | Kasago IPv4 Light | prior to Ver6.0.1.34 | Not stated |
| ZUKEN Elmic | Kasago mobile IPv6 | prior to Ver6.0.1.34 | 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. 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
KASAGO TCP/IP stack provided by Zuken Elmic generates ISNs(Initial Sequence Number) for TCP connections from an insufficiently random source. An attacker may be able to determine the ISN of the current or future TCP connections and either hijack existing ones or spoof future ones.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Insufficiently Random Values
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
How developers prevent this class of flaw
- Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds. In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts. Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a random enough number.
- Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
- Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems. Consult FIPS 140-2 Annex C (Approved Random Number Generators).
More Use of Insufficiently Random Values vulnerabilities (CWE-330)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- jvn.jp/en/vu/JVNVU99551468/Third Party Advisory
Recent Use of Insufficiently Random Values vulnerabilities
- 7.5 High severity
- 8.6 High severity
- 9.8 Critical severity
- 8.8 High severity
- 9.1 Critical severity
- 9.8 Critical severity
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