SEL-451: Insufficient Entropy
CVE-2023-31176 is a critical-severity insufficient entropy vulnerability in SEL-451 from Schweitzer Engineering Laboratories, 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. The record lists versions R315-V4, R316-V4, R317-V4 as the first without the flaw, so updating SEL-451 to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.93% chance of exploitation within 30 days, higher than 61% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update SEL-451 to R315-V4 or R316-V4 or R317-V4 or R318-V5, whichever matches your release line, or a later version.
- Update sel-451_firmware to R315-V4 or R316-V4 or R317-V4 or R318-V5, whichever matches your release line, or a later version.
- Read the advisory on selinc.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 |
|---|---|---|---|
| Schweitzer Engineering Laboratories | SEL-451 | R315-V0 up to, but not including, R315-V4; R316-V0 up to, but not including, R316-V4; R317-V0 up to, but not including, R317-V4; R318-V0 up to, but not including, R318-V5; R320-V0 up to, but not including, R320-V3; R321-V0 up to, but not including, R321-V3; R322-V0 up to, but not including, R322-V3; R323-V0 up to, but not including, R323-V5; and 4 more ranges | R315-V4, R316-V4, R317-V4, R318-V5, R320-V3, R321-V3 |
| Selinc | sel-451_firmware | R315-V0 up to, but not including, R315-V4; R316-V0 up to, but not including, R316-V4; R317-V0 up to, but not including, R317-V4; R318-V0 up to, but not including, R318-V5; R320-V0 up to, but not including, R320-V3; R321-V0 up to, but not including, R321-V3; R322-V0 up to, but not including, R322-V3; R323-V0 up to, but not including, R323-V5; and 4 more ranges | R315-V4, R316-V4, R317-V4, R318-V5, R320-V3, R321-V3 |
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 | 7.5 | High | CNA (selinc.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
An Insufficient Entropy vulnerability in the Schweitzer Engineering Laboratories SEL-451 could allow an unauthenticated remote attacker to brute-force session tokens and bypass authentication. See product Instruction Manual Appendix A dated 20230830 for more details.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Entropy
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.
How developers prevent this class of flaw
- Determine the necessary entropy to adequately provide for randomness and predictability. This can be achieved by increasing the number of bits of objects such as keys and seeds.
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
Third-party and government advisories
- nozominetworks.com/blog/Third Party Advisory
Other vulnerabilities in SEL-451
- 9.8 Critical severity
Recent Insufficient Entropy vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 8.1 High severity
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