OpenSSH vulnerability allows remote attackers to bypass integrity checks and downgrade security features

CVE-2023-48795

What is CVE-2023-48795?

CVE-2023-48795 is a notable vulnerability within the OpenSSH software suite, which is used for secure remote access to systems via the SSH protocol. This vulnerability allows remote attackers to bypass essential integrity checks, which may result in the downgrading or disabling of important security features during the connection handshake process. If exploited, this can severely compromise the confidentiality and integrity of data transmitted over SSH connections, exposing organizations to the risk of unauthorized access and data breaches.

Technical Details

The vulnerability arises from how certain OpenSSH extensions handle the handshake phase of the SSH Binary Packet Protocol (BPP) and manipulate sequence numbers. In particular, this flaw enables attackers to perform a Terrapin attack, which involves omitting specific packets in the extension negotiation message. As a result, both the client and server may establish a connection that inadvertently lacks some of the security guarantees they would typically expect, including vulnerabilities against the ChaCha20-Poly1305 and CBC with Encrypt-then-MAC MAC algorithms. This mismanagement poses significant risks to the security of SSH connections.

Potential Impact of CVE-2023-48795

1. Data Compromise: Exploitation of this vulnerability can lead to unauthorized access to sensitive data being transmitted over SSH channels, increasing the risk of data breaches and loss of confidentiality.

2. Downgraded Security Features: The ability to bypass integrity checks means that the security features of the SSH protocol can be weakened, rendering systems more vulnerable to other attacks and exploitation techniques.

3. Increased Attack Surface for Threat Actors: By allowing modifications to security protocols, this vulnerability presents an opportunity for attackers to execute more sophisticated attacks, thereby potentially facilitating further penetration into affected networks.

News Articles

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