CVE-2018-20685 : What You Need to Know

CVE-2018-20685 is a vulnerability in the scp client in OpenSSH 7.9 that allows remote SSH servers to override access restrictions, potentially leading to unauthorized modification of directory permissions on the client side.

Understanding CVE-2018-20685

The vulnerability in the scp client of OpenSSH 7.9 can be exploited by remote SSH servers to manipulate access restrictions, enabling unauthorized changes to directory permissions on the client's system.

What is CVE-2018-20685?

The scp client in OpenSSH 7.9 has a flaw in scp.c that permits remote SSH servers to bypass intended access limitations by using specific filenames, such as "." or an empty filename. This security issue enables unauthorized alterations to the permissions of the target directory on the client side.

The Impact of CVE-2018-20685

This vulnerability can result in unauthorized modifications to directory permissions on the client's system, potentially leading to security breaches and unauthorized access to sensitive data.

Technical Details of CVE-2018-20685

The technical aspects of CVE-2018-20685 provide insights into the vulnerability's description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The scp client in OpenSSH 7.9 allows remote SSH servers to override access restrictions, leading to unauthorized modifications of directory permissions on the client side.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions: All versions are affected.

Exploitation Mechanism

The vulnerability can be exploited by remote SSH servers using filenames like "." or an empty filename to manipulate access restrictions and modify directory permissions on the client side.

Mitigation and Prevention

Protecting systems from CVE-2018-20685 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update OpenSSH to the latest version to patch the vulnerability.
Monitor system logs for any suspicious activities related to SCP transfers.
Implement network segmentation to limit the impact of potential unauthorized modifications.

Long-Term Security Practices

Regularly update and patch all software and systems to prevent known vulnerabilities.
Conduct security audits and penetration testing to identify and address potential weaknesses.
Educate users on secure file transfer practices and the risks associated with SCP.

Patching and Updates

Apply patches provided by OpenSSH promptly to address the vulnerability and enhance system security.