CVE-2021-44228: Apache Log4j2 (Critical, CVSS 10)
- CVSS
- 10 Critical (v3.1)
- EPSS
- 100% chance of exploitation in the next 30 days (higher than 100% of CVEs)
- Exploited in the wild
- Yes, on CISA’s KEV list since Dec 10, 2021; used by ransomware
- Public exploit
- Yes, reported in a Metasploit module, Exploit-DB, a Nuclei template and 467 GitHub repositories
- Weakness
- CWE-20, CWE-400, CWE-502, CWE-917
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H- Published
- Dec 10, 2021
- CISA fix-by date
- Dec 24, 2021 (for US federal agencies)
What it is
Apache Log4j2 2.0-beta9 through 2.15.0 (excluding security releases 2.12.2, 2.12.3, and 2.3.1) JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From log4j 2.15.0, this behavior has been disabled by default. From version 2.16.0 (along with 2.12.2, 2.12.3, and 2.3.1), this functionality has been completely removed. Note that this vulnerability is specific to log4j-core and does not affect log4net, log4cxx, or other Apache Logging Services projects.
Description from the National Vulnerability Database.
What to do
CISA: For all affected software assets for which updates exist, the only acceptable remediation actions are: 1) Apply updates; OR 2) remove affected assets from agency networks. Temporary mitigations using one of the measures provided at https://www.cisa.gov/uscert/ed-22-02-apache-log4j-recommended-mitigation-measures are only acceptable until updates are available.
Check whether you run Apache Log4j2, then apply the vendor’s fix or mitigation from the advisories below. Because this flaw is exploited or has public exploit code, treat it as urgent and check for signs of compromise, not just the patch level.
Advisories and fixes
- seclists.org
- seclists.org
- www.openwall.com
- www.openwall.com
- www.openwall.com
- www.openwall.com
- www.openwall.com
- www.openwall.com
Sources: NVD, FIRST EPSS, CISA KEV, and public exploit databases (availability only). ThreatRoundup reports whether public exploit code exists but never links to it: fake proof-of-concepts that infect security researchers are common. This page updates automatically.