MELSEC-F Series FX3U-16MR/ES: Authentication Bypass by Capture-replay
CVE-2023-2846 is a critical-severity authentication bypass by capture-replay vulnerability in MELSEC-F Series FX3U-16MR/ES from Mitsubishi Electric, 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 MELSEC-F Series FX3U-16MR/ES versions: all versions. 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 MELSEC-F Series FX3U-16MR/ES you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on mitsubishielectric.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
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. 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 | 7.5 | High | CNA (yd.MitsubishiElectric.co.jp) |
| CVSS 3.1 | 9.1 | Critical | NVD |
Official description
Authentication Bypass by Capture-replay vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series main modules allows a remote unauthenticated attacker to cancel the password/keyword setting and login to the affected products by sending specially crafted packets.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Capture-replay
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
How developers prevent this class of flaw
- Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
- Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
More Authentication Bypass by Capture-replay vulnerabilities (CWE-294)
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
Advisories
Patches and release notes
- jvn.jp/vu/JVNVU94519952Mitigation, Third Party Advisory
- cisa.gov/news-events/ics-advisories/icsa-23-180-04Mitigation, Third Party Advisory, US Government Resource
Other vulnerabilities in MELSEC-F Series FX3U-16MR/ES
- 9.1 Critical severity
- 9.1 Critical severity
Recent Authentication Bypass by Capture-replay vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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