CVE-2023-48795 : What You Need to Know

A detailed analysis of the Terrapin attack, a vulnerability in the SSH transport protocol with certain OpenSSH extensions, affecting multiple products.

Understanding CVE-2023-48795

This section delves into the nature of the vulnerability, its impact, affected systems, and mitigation strategies.

What is CVE-2023-48795?

The CVE-2023-48795 vulnerability, known as the Terrapin attack, targets the SSH transport protocol with certain OpenSSH extensions. This flaw allows remote attackers to bypass integrity checks, leading to the omission of critical packets during the extension negotiation phase. Consequently, the connection may suffer from downgraded or disabled security features, posing a significant risk to affected systems.

The Impact of CVE-2023-48795

The Terrapin attack exploits weaknesses in the SSH Binary Packet Protocol (BPP) used by the vulnerable extensions. By mishandling the handshake phase and sequence numbers, attackers can compromise the security features of the SSH connections, notably affecting encryption algorithms like ChaCha20-Poly1305 and CBC with Encrypt-then-MAC.

Technical Details of CVE-2023-48795

This section provides specific technical information related to the vulnerability, including a description, affected systems and versions, and the exploitation mechanism.

Vulnerability Description

The bypass in the chacha20-poly1305@openssh.com algorithm and the -etm@openssh.com MAC algorithm enables the Terrapin attack. This vulnerability impacts several products, such as OpenSSH, Dropbear, PuTTY, AsyncSSH, and more.

Affected Systems and Versions

Numerous systems and versions are vulnerable to the Terrapin attack, including Maverick Synergy Java SSH API, PuTTY, libssh, Tera Term, Paramiko, and others listed in the CVE record.

Exploitation Mechanism

Attackers can exploit the CVE-2023-48795 vulnerability by manipulating the handshake phase and sequence numbers in the SSH connections. By omitting specific packets, they can compromise the integrity and security of the communication channel.

Mitigation and Prevention

This section outlines the immediate steps to take to address the CVE-2023-48795 vulnerability, secure long-term practices, and the importance of patching and updates.

Immediate Steps to Take

System administrators should update affected software and implement workarounds specified by vendors to mitigate the risk of exploitation. Additionally, monitoring network traffic for suspicious activities can help detect potential attacks.

Long-Term Security Practices

To enhance overall security posture, organizations should maintain up-to-date software, conduct regular security assessments, educate users on safe practices, and implement robust access controls and network segmentation.

Patching and Updates

Vendors have released patches to address the CVE-2023-48795 vulnerability. It is imperative for users to apply these patches promptly to safeguard their systems from potential Terrapin attacks.