CVE-2019-3861 Explained : Impact and Mitigation

A vulnerability known as an out of bounds read flaw has been identified in libssh2 versions earlier than 1.8.1. This flaw could allow a remote attacker to exploit the SSH server, potentially leading to a Denial of Service attack or unauthorized data access.

Understanding CVE-2019-3861

This CVE pertains to a specific vulnerability in libssh2 that affects versions prior to 1.8.1.

What is CVE-2019-3861?

The vulnerability in libssh2 versions before 1.8.1 involves parsing SSH packets with a padding length value exceeding the actual packet length. This flaw could be exploited by a remote attacker compromising an SSH server.

The Impact of CVE-2019-3861

If successfully exploited, this vulnerability could result in a Denial of Service attack or unauthorized access to and retrieval of data from the client's memory.

Technical Details of CVE-2019-3861

This section provides more in-depth technical details about the CVE.

Vulnerability Description

An out of bounds read flaw was discovered in libssh2 before version 1.8.1. It occurs during the parsing of SSH packets with a padding length value greater than the packet length.

Affected Systems and Versions

Product: libssh2
Vendor: The libssh2 Project
Vulnerable Version: 1.8.1 and earlier

Exploitation Mechanism

Attack Complexity: High
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality, Integrity, and Availability Impact: Low
CVSS Base Score: 5 (Medium)

Mitigation and Prevention

Protecting systems from CVE-2019-3861 requires immediate action and long-term security practices.

Immediate Steps to Take

Update libssh2 to version 1.8.1 or later to mitigate the vulnerability.
Monitor for any unusual SSH server behavior that could indicate a potential exploit.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Implement network segmentation and access controls to limit exposure to potential attacks.

Patching and Updates

Ensure that all relevant security patches and updates are consistently applied to the affected systems.