Protection against CVE-2021-45046, the additional Log4j RCE vulnerability
Dec 15, 2021Gabriel Gabor, Andre Bluehs
Summary
This post details the immediate mitigation of CVE-2021-45046, a second Log4j RCE vulnerability, by updating existing WAF rules (Rule IDs 100514/6b1cc72dff9746469d4695a474430f12, 100515/0c054d4e4dd5455c9ff8f01efe5abb10, 100516/5f6744fa026a4638bda5b3d7d5e015dd) to block exploit attempts targeting HTTP headers, body, and URL. It also introduces a fourth, advanced rule (Rule ID 100517/2c5413e155db4365befe0df160ba67d7) for broader protection with a higher false positive rate, which is disabled by default. The post emphasizes updating Log4j to version 2.16.0 as the primary solution.
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