Security Notice: SonicWall Email Security Zero-Day Vulnerabilities

Through the course of standard collaboration and testing, SonicWall has verified, tested and published patches to mitigate three zero-day vulnerabilities to its hosted and on-premises email security products.

In at least one known case, these vulnerabilities have been observed to be exploited ‘in the wild.’ It is imperative that organizations using SonicWall Email Security hardware appliances, virtual appliances or software installation on Microsoft Windows Server immediately upgrade to the respective SonicWall Email Security version listed below.

SonicWall Hosted Email Security (HES) was patched on April 19, 2021, and no action is required from organizations that are only using the hosted email security product.

Step-by-step guidance on how to apply the updates is available on an in-depth knowledgebase (KB) article.

Support for End-of-Life Email Security Products

SonicWall Email Security versions 7.0.0-9.2.2 are also impacted by the above vulnerabilities. However, these legacy versions have reached end of life (EOL) and are no longer supported. Organizations using these legacy product versions and have an active support license can download the latest Email Security versions from their MySonicWall account.

Customers without an active support license should contact their SonicWall SecureFirst partner to renew the license and upgrade to the latest SonicWall Email Security version. To find your local partner, please visit the SonicWall Partner Locator.

IPS Signatures Detect Exploitation

SonicWall has automatically deployed Intrusion Prevention System (IPS) signatures to help detect and block attacks that attempt to leverage the above vulnerabilities. The below signatures have already been applied to SonicWall firewalls with active security subscriptions.

• IPS Signature: 15520 WEB-ATTACKS SonicWall Email Security (CVE-2021-20022 Vulnerability)
• IPS Signature: 1067 WEB-ATTACKS Web Application Directory Traversal Attack 7
• IPS Signature: 15509 WEB-ATTACKS Web Application Directory Traversal Attack 7 -c2

About the CVEs

• CVE-2021-20021: Email Security Pre-Authentication Administrative Account Creation: A vulnerability in the SonicWall Email Security versions listed above could allow an attacker to potentially create an administrative account by sending a crafted HTTP request to the remote host.
• CVE-2021-20022: Email Security Post-Authentication Arbitrary File Creation: A vulnerability in the SonicWall Email Security versions listed above could allow a post-authenticated attacker to potentially upload an arbitrary file to the remote host.
• CVE-2021-20023: Email Security Post-Authentication Arbitrary File Read: A vulnerability in the SonicWall Email Security versions listed above could allow a post-authenticated attacker to potentially read an arbitrary file from the remote host.

For additional details on threat actor behavior, please review Mandiant's blog.