A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M580, Modicon M340, Legacy Controllers Modicon Quantum & Modicon Premium (see security notifications for affected versions), that could cause denial of service when a specially crafted Read Physical Memory request over Modbus is sent to the controller.

A CWE-255: Credentials Management vulnerability exists in Web Server on Modicon M340, Modicon Quantum and ModiconPremium Legacy offers and their Communication Modules (see security notification for version information) which could cause the execution of commands on the webserver without authentication when sending specially crafted HTTP requests.

Incorrect Authorization vulnerability exists in EcoStruxure Control Expert (all versions prior to 14.1 Hot Fix), Unity Pro (all versions), Modicon M340 (all versions prior to V3.20) , and Modicon M580 (all versions prior to V3.10), which could cause a bypass of the authentication process between EcoStruxure Control Expert and the M340 and M580 controllers.

Hard coded accounts exist in Schneider Electric's Modicon Premium, Modicon Quantum, Modicon M340, and BMXNOR0200 controllers in all versions of the communication modules.

A vulnerability exists in the HTTP request parser in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200 which could allow arbitrary code execution.

An authorization bypass vulnerability exists in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200. Requests to CGI functions allow malicious users to bypass authorization.

A buffer overflow vulnerability exists in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200. The buffer overflow vulnerability is caused by the length of the source string specified (instead of the buffer size) as the number of bytes to be copied.

A vulnerability exists in the web services to process SOAP requests in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200 which could allow result in a buffer overflow.

Vulnerable hash algorithms exists in Schneider Electric's Modicon Premium, Modicon Quantum, Modicon M340, and BMXNOR0200 controllers in all versions of the communication modules. The algorithm used to encrypt the password is vulnerable to hash collision attacks.

A Resource Exhaustion issue was discovered in Schneider Electric Modicon M340 PLC BMXNOC0401, BMXNOE0100, BMXNOE0110, BMXNOE0110H, BMXNOR0200H, BMXP341000, BMXP342000, BMXP3420102, BMXP3420102CL, BMXP342020, BMXP342020H, BMXP342030, BMXP3420302, BMXP3420302H, and BMXP342030H. A remote attacker could send a specially crafted set of packets to the PLC causing it to freeze, requiring the operator to physically press the reset button on the PLC in order to recover.