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CVE-2018-7811: An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium…

CVE-2018-7811 is rated critical with a CVSS v3.0 base score of 9.8 and NVD lists 4 affected products, including Schneider Electric Modicom M340 Firmware. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 which could allow an unauthenticated remote user to access the change password function of the web server

Severity breakdown

CVSS v3.0 9.8: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-640: Weak Password Recovery Mechanism for Forgotten Password

The product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak.

Affected products

  • Schneider Electric Modicom M340 Firmware: all versions listed by NVD
  • Schneider Electric Modicom Premium Firmware: all versions listed by NVD
  • Schneider Electric Modicom Quantum Firmware: all versions listed by NVD
  • Schneider Electric Modicom Bmxnor0200h Firmware: all versions listed by NVD

References