CVE-2017-6034
Schneider Electric Modicon Modbus Protocol Authentication Bypass by Capture-replay
- Published
- Updated
- Reserved
- Assigned by
- icscert
Description
An authentication bypass by capture-replay issue was discovered in Schneider Electric Modicon Modbus Protocol. Sensitive information is transmitted in cleartext in the Modicon Modbus protocol, which may allow an attacker to replay the following commands: run, stop, upload, and download.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 5.6% · top 7.1% of all CVEs (3 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Weakness
Affected products
Schneider Electric · Modicon Modbus Protocol
- affected all versions
What to do
Workaround: Schneider Electric has reported that they have introduced compensating controls to limit the exploitability of the identified vulnerabilities in many of the PLCs in the Modicon family; however, Schneider Electric recommends that users apply security measures to improve resiliency. Schneider Electric’s Momentum M1E controllers (all versions of model 171CBU98090 and all versions of model 171CBU98091) do not have built-in compensating controls to limit the exploitability of the identified vulnerabilities and Schneider Electric instructs users to take the following defensive measures: * Protect access to M1E controllers by a firewall blocking all remote/external access to Port 502. Schneider Electric reports that Modicon M340, M580, Premium and Quantum users should take one or more of the following defensive measures: * Enable protection based on an authentication to connect to PLC. This method relies on a feature named Application Password. Once enabled, password-based authentication is required whenever a user connects to change their application program; * Enable protection relying on an input (M340, Premium, Quantum) or a key switch in the front panel (Quantum) to reject remote connection or run/stop commands; and * Enable the “Access Control List protection,” where users are able to configure the restricted IP addresses that are pre-authorized to control the PLC. For additional information, Schneider Electric has released a Cybersecurity Notification, which is available at the following location: https://www.se.com/us/en/download/document/SEVD-2017-065-01/
References (4)
- https://ics-cert.us-cert.gov/advisories/ICSA-17-101-01 (opens in a new tab)x_refsource_MISCx_transferred
- 97562 (opens in a new tab)vdb-entryx_refsource_BIDx_transferred
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2017/icsa-17-101-01.json (opens in a new tab)
- https://www.se.com/us/en/download/document/SEVD-2017-065-01/ (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2017-6034)Record last updated .