This is the largest vulnerability we have seen in years.

  1. You may still be vulnerable even if your project is not based on Java. Many tech stacks are vulnerable because so many tools use the Log4js including infrastructure, dev-tools, and CI/CD products.
  2. Log4Shell will be here for a while. Log4j is a basic core component that is already in use in many products, including network devices, management consoles, and enterprise software and hardware. They just cannot be upgraded in a few days.
  3. Companies may still be vulnerable even if the vulnerable host is deep inside its network perimeter. The root cause of this issue is a simple string that could be logged by a vulnerable server through many hops — and trigger the remote code execution somewhere deep inside the perimeter.
  4. There will be breaches. So, yes your personal private data is at risk as well. On Github, someone has posted screenshots of successful exploitation resources of large enterprises including Apple, Tesla, and Microsoft services.
  5. WAFs can’t protect in full. The exploit can come through any protocol, including APIs like gRPC and GraphQL, or for example DNS or UDP. WAFs are not really helpful here.


See how Wallarm addresses the Log4j vulnerability for its customers in the relevant blogpost.