A Log4Shell (Log4j) Retrospective

Arctic Wolf Labs reviews the one-year impact of the Log4Shell (CVE-2021-44228) vulnerability, reporting continued large-scale scanning and exploitation (63,313 unique incidents affecting ~25% of customers), that Log4Shell was the root cause in 11% of incident response engagements in 2022, frequent attribution to major ransomware groups (LockBit, Conti, Alphv/BlackCat), average remediation costs exceeding US$90,000, and provides mitigation guidance including an open-source Log4Shell Deep Scan tool.