CVE-2021-33737 Denial of service in SIMATIC CP 343-1 (incl. SIPLUS variants)
A remote attacker can cause a denial of service on Siemens SIMATIC communication processors by sending a specially crafted packet to port 102/tcp.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-33737?
CVE-2021-33737 is a high-severity denial of service vulnerability in Siemens SIMATIC CP 343-1 (incl. SIPLUS variants), published on 14 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability has been identified in SIMATIC CP 343-1 (incl. SIPLUS variants) (All versions), SIMATIC CP 343-1 Advanced (incl. SIPLUS variants) (All versions), SIMATIC CP 343-1 ERPC (All versions), SIMATIC CP 343-1 Lean (incl. SIPLUS variants) (All versions), SIMATIC CP 443-1 (All versions < V3.3), SIMATIC CP 443-1 (All versions < V3.3), SIMATIC CP 443-1 Advanced (All versions < V3.3), SIPLUS NET CP 443-1 (All versions < V3.3), SIPLUS NET CP 443-1 Advanced (All versions < V3.3). Sending a specially crafted packet to port 102/tcp of an affected device could cause a denial of service condition. A restart is needed to restore normal operations.
Weakness: CWE-119
Which versions are affected by CVE-2021-33737?
It affects 6 products.
Products include Siemens Simatic Cp 343-1 Advanced Firmware, Siemens Simatic Cp 343-1 Erpc Firmware, Siemens Simatic Cp 343-1 Firmware, Siemens Simatic Cp 343-1 Lean Firmware, Siemens Simatic Cp 443-1 Advanced Firmware, Siemens Simatic Cp 443-1 Firmware.
How do I fix CVE-2021-33737?
No fix has been published for CVE-2021-33737 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-33737 being exploited?
There is no known exploitation of CVE-2021-33737 in the wild and no public exploit code.
Sources
Also known as GHSA-w34c-jjqq-3824.