Actively exploited · Published Dec 14, 2021 · Assigned by apache
CVE-2021-45046Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack
Critical 9.0 Exploited Ransomware
In plain English
A critical-severity expression language injection in Apache Log4j from Apache Software Foundation. Attackers are actively exploiting it in the wild (listed by CISA on May 1, 2023). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 100.0% (higher than 99.9% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit, Nuclei, public proof-of-concept code. Fixed versions are available - upgrade the affected package.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by May 22, 2023.
Official description
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | apache-log4j2 | 2.16.0-1 | DEBIAN-CVE-2021-45046 |
| Debian:13 | apache-log4j2 | 2.16.0-1 | DEBIAN-CVE-2021-45046 |
| Debian:14 | apache-log4j2 | 2.16.0-1 | DEBIAN-CVE-2021-45046 |
| Maven | org.apache.logging.log4j:log4j-core | 2.16.0 | GHSA-7rjr-3q55-vv33 |
| Maven | org.apache.logging.log4j:log4j-core | 2.12.2 | GHSA-7rjr-3q55-vv33 |
| Maven | org.apache.logging.log4j:log4j-core | 2.3.1 | GHSA-7rjr-3q55-vv33 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | 1.9.2 | GHSA-7rjr-3q55-vv33 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | 1.11.11 | GHSA-7rjr-3q55-vv33 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | 1.10.8 | GHSA-7rjr-3q55-vv33 |
| Maven | org.ops4j.pax.logging:pax-logging-log4j2 | 2.0.12 | GHSA-7rjr-3q55-vv33 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Log4j | Apache Log4j2 – before 2.16.0 |
Weakness: CWE-917 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
References
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032 x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/alert-cve-2021-44228.html x_refsource_CONFIRM
- https://www.cve.org/CVERecord?id=CVE-2021-44228 x_refsource_MISC
- [oss-security] 20211214 CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack mailing-list, x_refsource_MLIST
- https://logging.apache.org/log4j/2.x/security.html x_refsource_CONFIRM
- VU#930724 third-party-advisory, x_refsource_CERT-VN
- https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf x_refsource_CONFIRM
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html x_refsource_CONFIRM
- 20211210 Vulnerabilities in Apache Log4j Library Affecting Cisco Products: December 2021 vendor-advisory, x_refsource_CISCO
- [oss-security] 20211215 Re: CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack mailing-list, x_refsource_MLIST
- https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf x_refsource_CONFIRM
- DSA-5022 vendor-advisory, x_refsource_DEBIAN
- [oss-security] 20211218 Re: CVE-2021-45046: Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack mailing-list, x_refsource_MLIST
- https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf x_refsource_CONFIRM
- FEDORA-2021-5c9d12a93e vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-abbe24e41c vendor-advisory, x_refsource_FEDORA
- https://www.oracle.com/security-alerts/cpujan2022.html x_refsource_MISC
- https://www.oracle.com/security-alerts/cpuapr2022.html x_refsource_MISC
- https://www.oracle.com/security-alerts/cpujul2022.html x_refsource_MISC
- https://security.gentoo.org/glsa/202310-16
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046 government-resource