Row Hammer Attack Vulnerability in OpenSSH by OpenBSD

CVE-2023-51767

What is CVE-2023-51767?

CVE-2023-51767 is a vulnerability affecting OpenSSH, an open-source implementation of the Secure Shell (SSH) protocol used widely for secure data communication and remote command execution. This issue arises specifically in versions up to 9.6, where it opens the door for row hammer attacks targeting certain types of dynamic random-access memory (DRAM). The flaw is due to inadequate resilience in the integer value of the authenticated variable within the mm_answer_authpassword function, which does not adequately withstand single-bit flips. A successful exploitation of this vulnerability could enable an attacker with user privileges to bypass authentication, potentially gaining unauthorized access to sensitive systems and data. This is particularly problematic in environments where attackers and victims are co-located, as it raises the risk of direct access and manipulation.

Potential impact of CVE-2023-51767

1. Authentication Bypass: The primary risk associated with this vulnerability is the ability for attackers to bypass authentication procedures, which can lead to unauthorized access to systems. This exposes organizations to data theft, malicious alterations, or further exploitation of the network.

2. Co-location Threat Model Exploitation: The vulnerability is especially concerning in scenarios where attackers and victims share physical resources. This appropriate threat model implies that an attacker could exploit the vulnerability more easily, compromising systems in cloud computing or shared server environments.

3. Increased Attack Surface: By allowing for potential unauthorized access via a sophisticated attack method, the vulnerability heightens the attack surface within any organization utilizing affected versions of OpenSSH. Failure to address this vulnerability could lead to cascading security incidents, where compromised systems act as launch pads for broader network infiltrations.

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