CVE-2018-7838 : Security Advisory and Response

A vulnerability known as CWE-119 Buffer Errors affects Modicon M580 CPU - BMEP582040 and Modicon Ethernet Module BMENOC0301, leading to denial of service when FTP commands exceed a certain length.

Understanding CVE-2018-7838

This CVE involves a specific vulnerability in Modicon devices that can disrupt FTP services, requiring a power cycle to restore functionality.

What is CVE-2018-7838?

The vulnerability in Modicon M580 CPU and Ethernet Module BMENOC0301 allows for a denial of service when FTP commands surpass a certain length, impacting versions prior to V2.90 and V2.16, respectively.

The Impact of CVE-2018-7838

The vulnerability can result in a denial of service when the FTP service of the controller or Ethernet module receives a FTP CWD command with excessive data length, necessitating a power cycle to resume FTP operations.

Technical Details of CVE-2018-7838

This section delves into the technical aspects of the CVE.

Vulnerability Description

The CWE-119 Buffer Errors vulnerability in Modicon devices causes a denial of service when FTP commands exceed 1020 bytes in length.

Affected Systems and Versions

Modicon M580 CPU - BMEP582040 all versions before V2.90
Modicon Ethernet Module BMENOC0301 all versions before V2.16

Exploitation Mechanism

Sending FTP CWD commands with a data length exceeding 1020 bytes

Mitigation and Prevention

Protecting systems from CVE-2018-7838 is crucial to maintain security.

Immediate Steps to Take

Apply vendor-supplied patches promptly
Monitor network traffic for any suspicious activity
Implement firewall rules to restrict FTP traffic

Long-Term Security Practices

Regularly update firmware and software to the latest versions
Conduct security assessments and penetration testing
Educate users on safe FTP practices

Patching and Updates

Schneider Electric provides patches to address the vulnerability
Regularly check for updates and apply them to ensure system security