Arbitrary file upload in SonicWall On-premise Email Security (ES) and SonicWall Hosted Email Security (HES) - CVE-2021-20022

Vulnerability details

The vulnerability allows a remote user to compromise vulnerable system.

The vulnerability exists due to insufficient validation of file during file upload within the branding feature. A remote administrator can upload a malicious ZIP archive to the system to an arbitrary location using directory traversal sequences in the filenames inside the uploaded archive and compromise the affected system.

Note, the vulnerability is being actively exploited in the wild.

Affected software

How to mitigate CVE-2021-20022

External References

• https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0008
• https://www.fireeye.com/blog/threat-research/2021/04/zero-day-exploits-in-sonicwall-email-security-lead-to-compromise.html

Related Security Bulletins

• Multiple vulnerabilities in SonicWall On-premise Email Security (ES) and Hosted Email Security (HES)