mergebase/log4j-detectorFile-system scanner that detects vulnerable Log4J versions (CVE-2021-44228, CVE-2021-45046) by analyzing compiled Java classes, including nested archives. Works on Linux, Windows, and Mac.
Scanner that detects vulnerable Log4J versions to help teams assess their exposure to CVE-2021-44228 (CRITICAL), CVE-2021-45046, CVE-2021-45105, and CVE-2021-44832. Can search for Log4J instances by carefully examining the complete file-system, including all installed applications. It is able to find Log4J instances that are hidden several layers deep. Works on Linux, Windows, and Mac, and everywhere else Java runs, too!
log4j-core Library. What About log4j-api? Currently reports log4j-core versions 2.3.2, 2.12.4, and 2.17.1 as _SAFE_, 2.3.1, 2.12.2, 2.12.3, 2.15.0, 2.16.0, and 2.17.0 as _OKAY_ and all other versions as _VULNERABLE_ (although it does report pre-2.0-beta9 as _POTENTIALLY_SAFE_). It reports older log4j-1.x versions as _OLD_.
Can correctly detect log4j inside executable spring-boot jars/wars, dependencies blended into uber jars, shaded jars, and even exploded jar files just sitting uncompressed on the file-system (aka *.class).
We currently maintain a collection of log4j-samples we use for testing.
java -jar log4j-detector-2021.12.29.jar ./samples
-- github.com/mergebase/log4j-detector v2021.12.29 (by mergebase.com) analyzing paths (could take a while).
-- Note: specify the '--verbose' flag to have every file examined printed to STDERR.
false-hits/log4j-core-2.12.2.jar contains Log4J-2.x == 2.12.2 _OKAY_
false-hits/log4j-core-2.12.3.jar contains Log4J-2.x == 2.12.3 _OKAY_
false-hits/log4j-core-2.12.4.jar contains Log4J-2.x == 2.12.4 _SAFE_
false-hits/log4j-core-2.15.0.jar contains Log4J-2.x == 2.15.0 _OKAY_
false-hits/log4j-core-2.16.0.jar contains Log4J-2.x == 2.16.0 _OKAY_
false-hits/log4j-core-2.17.0.jar contains Log4J-2.x == 2.17.0 _OKAY_
false-hits/log4j-core-2.17.1.jar contains Log4J-2.x >= 2.17.1 _SAFE_
false-hits/log4j-core-2.3.1.jar contains Log4J-2.x == 2.3.1 _OKAY_
false-hits/log4j-core-2.3.2.jar contains Log4J-2.x == 2.3.2 _SAFE_
true-hits/log4j-core-2.0-beta9.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
true-hits/log4j-core-2.10.0.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.10.0.zip contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.11.0.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.11.1.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.11.2.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.12.0.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.12.1.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.14.0.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.14.1.jar contains Log4J-2.x >= 2.10.0 _VULNERABLE_
true-hits/log4j-core-2.2.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
true-hits/log4j-core-2.3.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
true-hits/log4j-core-2.4.1.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
true-hits/log4j-core-2.4.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
true-hits/log4j-core-2.9.1.jar contains Log4J-2.x >= 2.0-beta9 (< 2.10.0) _VULNERABLE_
old-hits/log4j-1.1.3.jar contains Log4J-1.x <= 1.2.17 _OLD_
old-hits/log4j-1.2.17.jar contains Log4J-1.x <= 1.2.17 _OLD_
old-hits/log4j-core-2.0-beta2.jar contains Log4J-2.x <= 2.0-beta8 _POTENTIALLY_SAFE_ (Did you remove JndiLookup.class?)
_VULNERABLE_ -> You need to upgrade or remove this file.
_OKAY_ -> We report this for Log4J versions 2.3.1, 2.12.2, 2.12.3, 2.15.0, 2.16.0, and 2.17.0. We recommend upgrading to 2.17.1.
_SAFE_ -> We currently only report this for Log4J versions 2.3.2, 2.12.4, and 2.17.1 (and greater).
_OLD_ -> You are safe from CVE-2021-44228, but should plan to upgrade because Log4J 1.2.x has been EOL for 7 years and has several known-vulnerabilities.
_POTENTIALLY_SAFE_ -> The "JndiLookup.class" file is not present, either because your version of Log4J is very old (pre 2.0-beta9), or because someone already removed this file. Make sure it was someone in your team or company that removed "JndiLookup.class" if that's the case, because attackers have been known to remove this file themselves to prevent additional competing attackers from gaining access to compromised systems.
java -jar log4j-detector-2021.12.29.jar
Usage: java -jar log4j-detector-2021.12.29.jar [--verbose] [--json] [--stdin] [--exclude=X] [paths to scan...]
--json - Output STDOUT results in JSON. (Errors/warning still emitted to STDERR)
--stdin - Read STDIN for paths to explore (one path per line)
--exclude=X - Where X is a JSON list containing full paths to exclude. Must be valid JSON.
Example: --exclude='["/dev", "/media", "Z:\TEMP"]'
Exit codes: 0 = No vulnerable Log4J versions found.
1 = At least one legacy Log4J 1.x version found.
2 = At least one vulnerable Log4J version found.
About - MergeBase log4j detector (version 2021.12.29)
Docs - https://github.com/mergebase/log4j-detector
(C) Copyright 2021 Mergebase Software Inc. Licensed to you via GPLv3.
git clone https://github.com/mergebase/log4j-detector.git
cd log4j-detector/
mvn install
java -jar target/log4j-detector-latest.jar
We maintain a collection of log4j samples here: https://github.com/mergebase/log4j-samples
GPL version 3.0
The Java compiler stores String literals directly in the compiled *.class files. If log4j-detector detects a file named "JndiManager.class" on your file-system, it then examines that file for this String: "Invalid JNDI URI - {}". Turns out that specific String literal is only present in the patched version of Log4J (version 2.15.0). Any versions of Log4J without that String are vulnerable.
This same technique of examining *.class files for String literals is further extended to accurately detect safe versions 2.3.2, 2.12.4, and 2.17.1.
log4j-core Library. What About log4j-api?