# google/log4jscanner

A log4j vulnerability filesystem scanner and Go package for analyzing JAR files.

Repository: https://github.com/google/log4jscanner
Canonical: https://ross.abutalabs.com/products/log4jscanner
Language: Go
License: Apache-2.0
License Family: permissive
Archived: true
Last push: 2022-06-30T03:03:00+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 1709, "days_push": 1525, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1562, forks 113 (observed 2026-08-28T04:05:04.003598+00:00)

## What it is
A Go-based filesystem scanner and library that detects JAR files containing the vulnerable Log4j classes behind the Log4Shell vulnerability (CVE-2021-44228). It can optionally rewrite JARs in place to remove the vulnerable JndiLookup class.

## Use cases
- scan a filesystem for log4j vulnerable jars
- find servers affected by log4shell
- remove JndiLookup class from vulnerable jars
- analyze jar files for log4j vulnerability in Go
- audit dependencies for CVE-2021-44228
- scan entire root filesystem for log4j

## When to choose
- you need to quickly identify or remediate Log4Shell exposure across a filesystem
- you want a Go library to programmatically inspect JARs for the vulnerable log4j classes

## When to avoid
- you need general-purpose Java dependency or SBOM scanning beyond log4j
- the vulnerability has been patched at source and you no longer need ad-hoc scanning

## Facets
- artifact type: cli-tool
- maturity: maintenance
- function: security, vulnerability-scanning, parser, cli, developer-tools
- domain: security, developer-tools, files
- platform: windows, cross-platform, go, cli
- tags: log4j, log4shell, jar-analysis, cve-2021-44228, filesystem-scanner, java, command-line, linux, macos

## Member repositories
- google/log4jscanner (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:04.003598+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:00:17.592746+00:00, confidence not recorded.
  - readme: https://github.com/google/log4jscanner (fetched 2026-08-28T04:05:04.003598+00:00, sha 4272d408cb12)
- Data as of 2026-08-30T08:39:29.467469+00:00.