Schneider Electric Modicon Modbus Protocol Authentication Bypass by Capture-replay
Summary
| CVE | CVE-2017-6034 |
|---|---|
| State | PUBLISHED |
| Assigner | icscert |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2017-06-30 03:29:00 UTC |
| Updated | 2026-06-04 22:16:51 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 9.8 CRITICAL from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001440000 probability, percentile 0.344240000 (date 2026-06-09)
Problem Types: CWE-294 | CWE-287 | CWE-294 CWE-294
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | DECLARED | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.0 | [email protected] | Primary | 9.8 | CRITICAL | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 2.0 | [email protected] | Primary | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v3.0 Breakdown
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v2.0 Breakdown
AV:N/AC:L/Au:N/C:P/I:P/A:P
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Hardware | Schneider-electric | Modbus | - | All | All | All |
| Operating System | Schneider-electric | Modbus Firmware | - | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Schneider Electric | Modicon Modbus Protocol | affected all versions | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| Schneider Electric Modicon Modbus Protocol Multiple Authentication Bypass Vulnerabilities | af854a3a-2127-422b-91ae-364da2661108 | www.securityfocus.com | Third Party Advisory, VDB Entry |
| www.se.com/us/en/download/document/SEVD-2017-065-01 | [email protected] | www.se.com | |
| github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2017/icsa-17-10... | [email protected] | github.com | |
| Schneider Electric Modicon Modbus Protocol | ICS-CERT | af854a3a-2127-422b-91ae-364da2661108 | ics-cert.us-cert.gov | Third Party Advisory, US Government Resource |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Eran Goldstein of CRITIFENCE reported the identified vulnerabilities. (en)
Additional Advisory Data
Workarounds
CNA: 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/
Legacy QID Mappings
- 590766 Schneider Electric Modicon Controllers and SCADAPack RTU Vulnerability (SEVD-2017-065-01)