CVE-2023-33009 Zyxel Multiple Firewalls: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Jun 26, 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 Buffer Overflow Vulnerability
- Product
- Zyxel Multiple Firewalls
- CISA description
- Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the notification function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.
- Type of flaw
- Memory-safety flaw (CWE-120)
- Confirmed exploited
- Jun 5, 2023
- US federal patch deadline
- Jun 26, 2023
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Answering about CVE-2023-33009 ·
Questions about CVE-2023-33009
Is CVE-2023-33009 being exploited?
Yes. CISA added CVE-2023-33009 to its Known Exploited Vulnerabilities catalog on Jun 5, 2023, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2023-33009?
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-2023-33009?
Only if you use Zyxel Multiple Firewalls. This one is aimed at devices or apps of the kind people own.