Apache Log4j Message Lookup Substitution RCE (Log4Shell) (Direct Check)

critical Nessus Plugin ID 155998


The version of Apache Log4j used on the remote server is affected by a remote code execution vulnerability.


A remote code execution vulnerability exists in Apache Log4j < 2.15.0 due to insufficient protections on message lookup substitutions when dealing with user controlled input. A remote, unauthenticated attacker can explolit this, via a web request to execute arbitrary code with the permission level of the running Java process.

The plugin relies on callbacks from the target being scanned and hence any firewall rules or interaction with other security devices will affect the efficacy of the plugin. The plugin will also not yield results on Tenable.io and customers are encouraged to use plugin IDs 155999, 156000, 156001, and 156002 instead when scanning with Tenable.io. We continue to explore options for additional detection.

This plugin will have the scanner listen for the callback on a random port in the 50000 to 60000 range.


Upgrade to Apache Log4j version 2.15.0 or later, or apply the vendor mitigation.

Upgrading to the latest versions for Apache Log4j is highly recommended as intermediate versions / patches have known high severity vulnerabilities and the vendor is updating their advisories often as new research and knowledge about the impact of Log4j is discovered. Refer to https://logging.apache.org/log4j/2.x/security.html for the latest versions.

See Also



Plugin Details

Severity: Critical

ID: 155998

File Name: apache_log4j_jdni_ldap_generic.nbin

Version: 1.47

Type: remote

Family: Web Servers

Published: 12/10/2021

Updated: 3/19/2024

Supported Sensors: Nessus

Risk Information


Risk Factor: Critical

Score: 10.0


Risk Factor: High

Base Score: 9.3

Temporal Score: 8.1

Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2021-44228


Risk Factor: Critical

Base Score: 10

Temporal Score: 9.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:apache:log4j

Exploit Available: true

Exploit Ease: Exploits are available

Exploited by Nessus: true

Patch Publication Date: 12/10/2021

Vulnerability Publication Date: 12/9/2021

CISA Known Exploited Vulnerability Due Dates: 12/24/2021

Exploitable With


Core Impact

Reference Information

CVE: CVE-2021-44228

IAVA: 0001-A-0650, 2021-A-0573, 2021-A-0596, 2021-A-0597, 2021-A-0598