Microsoft revised the severity rate for the CVE-2022-37958 flaw which was addressed with Patch Tuesday security updates for September 2022.

Microsoft revised the severity rate for the CVE-2022-37958 vulnerability, the IT giant now rated it as “critical” because it discovered that threat actors can exploit the bug to achieve remote code execution.

The CVE-2022-37958 was originally classified as an information disclosure vulnerability that impacts the SPNEGO Extended Negotiation (NEGOEX) security mechanism.

The SPNEGO Extended Negotiation Security Mechanism (NEGOEX) extends Simple and Protected GSS-API Negotiation Mechanism (SPNEGO) described in [RFC4178].

The SPNEGO Extended Negotiation (NEGOEX) Security Mechanism allows a client and server to negotiate the choice of security mechanism to use.

The issue was initially rated as high severity because the successful exploitation of this issue required an attacker to prepare the target environment to improve exploit reliability.

Microsoft addressed the vulnerability with the release of Patch Tuesday security updates for September 2022.

IBM Security X-Force researcher Valentina Palmiotti demonstrated that this vulnerability is a pre-authentication remote code execution issue that impacts a wide range of protocols. It has the potential to be wormable and can be exploited to achieve remote code execution.

“The vulnerability could allow attackers to remotely execute arbitrary code by accessing the NEGOEX protocol via any Windows application protocol that authenticates, such as Server Message Block (SMB) or Remote Desktop Protocol (RDP), by default.” reads the post published by IBM. “This list of affected protocols is not complete and may exist wherever SPNEGO is in use, including in Simple Message Transport Protocol (SMTP) and Hyper Text Transfer Protocol (HTTP) when SPNEGO authentication negotiation is enabled, such as for use with Kerberos or Net-NTLM authentication.”

Unlike the CVE-2017-0144 flaw triggered by the EternalBlue exploit, which only affected the SMB protocol, the CVE-2022-37958 flaw could potentially affect a wider range of Windows systems due to a larger attack surface of services exposed to the public internet (HTTP, RDP, SMB) or on internal networks. The expert pointed out that this flaw can be exploited without user interaction or authentication.

IBM announced it will release full technical details in Q2 2023 to give time organizations to apply the security updates.

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Pierluigi Paganini

(SecurityAffairs – hacking, CVE-2022-37958)

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