CVE-2021-20022 SonicWall SonicWall Email Security: dangerous file upload
In plain words: The program accepts files it should refuse, such as programs disguised as ordinary uploads. The attacker can place and run their own tools on the server.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2021
What to do
- Install SonicWall's security update for SonicWall Email Security. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- SonicWall Email Security Unrestricted Upload of File Vulnerability
- Product
- SonicWall SonicWall Email Security
- CISA description
- SonicWall Email Security contains an unrestricted upload of file with dangerous type vulnerability that allows a post-authenticated attacker to upload a file to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20023 to achieve privilege escalation.
- Type of flaw
- Dangerous file upload (CWE-434)
- Confirmed exploited
- Nov 3, 2021 — known to be used in ransomware attacks
- US federal patch deadline
- Nov 17, 2021
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Answering about CVE-2021-20022 ·
Questions about CVE-2021-20022
Is CVE-2021-20022 being exploited?
Yes. CISA added CVE-2021-20022 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-20022?
Install SonicWall's security update for SonicWall Email Security. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2021-20022?
Only if you use SonicWall SonicWall Email Security. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.