#VU52039 Arbitrary file upload in SonicWall On-premise Email Security (ES) and SonicWall Hosted Email Security (HES) - CVE-2021-20022

Vulnerability identifier: #VU52039

Vulnerability risk: High

CVSSv4.0: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber]

CVE-ID: CVE-2021-20022

CWE-ID: CWE-434

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
SonicWall On-premise Email Security (ES)
Client/Desktop applications / Antivirus software/Personal firewalls
SonicWall Hosted Email Security (HES)
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: SonicWall

Description

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.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

SonicWall On-premise Email Security (ES): before 10.0.9.6103

SonicWall Hosted Email Security (HES): before 10.0.9.6103

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External links
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

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.