CVE-2023-28771 Zyxel Multiple Firewalls: command or code injection
In plain words: The program treats text it receives as instructions instead of plain data. The attacker can run commands on the machine — often the whole device is taken over.
Confirmed exploited by CISA on · US federal patch deadline Jun 21, 2023
What to do
- Install Zyxel's security update for Multiple Firewalls. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Turn on automatic firmware updates and replace gear the maker no longer supports.
- Change default passwords and switch off remote administration and features you do not use.
- Do not put storage boxes or cameras directly on the internet — use the maker's app or a VPN.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Taken over in bulk to join botnets, used to watch your traffic, or — for storage boxes — locked by ransomware.
The details
- Official name
- Zyxel Multiple Firewalls OS Command Injection Vulnerability
- Product
- Zyxel Multiple Firewalls
- CISA description
- Zyxel ATP, USG FLEX, VPN, and ZyWALL/USG firewalls allow for improper error message handling which could allow an unauthenticated attacker to execute OS commands remotely by sending crafted packets to an affected device.
- Type of flaw
- Command or code injection (CWE-78)
- Confirmed exploited
- May 31, 2023
- US federal patch deadline
- Jun 21, 2023
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Answering about CVE-2023-28771 ·
Questions about CVE-2023-28771
Is CVE-2023-28771 being exploited?
Yes. CISA added CVE-2023-28771 to its Known Exploited Vulnerabilities catalog on May 31, 2023, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2023-28771?
Install Zyxel's security update for Multiple Firewalls. If no update exists, follow the vendor's workaround or stop using the product until one ships. Turn on automatic firmware updates and replace gear the maker no longer supports.
Am I affected by CVE-2023-28771?
Only if you use Zyxel Multiple Firewalls. This one is aimed at devices or apps of the kind people own.