CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability exists that could cause a vulnerability leading to a cross-site scripting condition where attackers can have a victim’s browser run arbitrary JavaScript when they visit a page containing the injected payload.

Improper Input Validation vulnerability exists in Modicon M241/M251 logic controllers firmware prior to V5.1.9.1 that could cause denial of service when specific crafted requests are sent to the controller over HTTP.

A CWE-319: Cleartext Transmission of Sensitive Information vulnerability exists which could leak sensitive information transmitted between the software and the Modicon M218, M241, M251, and M258 controllers.

A CWE-345: Insufficient Verification of Data Authenticity vulnerability exists which could allow the attacker to execute malicious code on the Modicon M218, M241, M251, and M258 controllers.

A CWE-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address, network mask and gateway IP address) when a specific Ethernet frame is received in all versions of: Modicon M100, Modicon M200, Modicon M221, ATV IMC drive controller, Modicon M241, Modicon M251, Modicon M258, Modicon LMC058, Modicon LMC078, PacDrive Eco ,PacDrive Pro, PacDrive Pro2

A Predictable Value Range from Previous Values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.

An Insufficiently Protected Credentials issue was discovered in Schneider Electric Modicon PLCs Modicon M241, all firmware versions, and Modicon M251, all firmware versions. Log-in credentials are sent over the network with Base64 encoding leaving them susceptible to sniffing. Sniffed credentials could then be used to log into the web application.

A Use of Insufficiently Random Values issue was discovered in Schneider Electric Modicon PLCs Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The session numbers generated by the web application are lacking randomization and are shared between several users. This may allow a current session to be compromised.