Apache Log4j2 Deserialization of Untrusted Data Vulnerability
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…
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 5 / 5
- KEV catalog (CISA)01 May 2023
- Exploited in EUVD (ENISA)01 May 2023
- Used by ransomwareyes
- EPSS above 10 %99.98%
- No account, over the networkyes
What to do
Fix
Update to a fixed version: 2.16.0 2.12.2 2.3.1
CISA guidance: Apply updates per vendor instructions.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Description ENISA EUVD
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 products
- Apache Log4j2 <2.16.0
Open source packages OSV
- org.apache.logging.log4j:log4j-coreMaven · GHSA-7rjr-3q55-vv33fixed in 2.16.0
- org.apache.logging.log4j:log4j-coreMaven · GHSA-7rjr-3q55-vv33fixed in 2.12.2
- org.apache.logging.log4j:log4j-coreMaven · GHSA-7rjr-3q55-vv33fixed in 2.3.1
Timeline
-
Published
-
Exploitation reported (ENISA)
-
Added to the KEV catalog
-
CISA remediation due date
-
EPSS peak: 99.98%
References
- cve.org · CVE-2021-45046
- ENISA EUVD · EUVD-2021-34769
- CISA KEV
- FIRST EPSS
- psirt.global.sonicwall.com
- oracle.com
- cve.org
- openwall.com
- logging.apache.org
- kb.cert.org
- cert-portal.siemens.com
- intel.com
- tools.cisco.com
- openwall.com
- cert-portal.siemens.com
- debian.org
- openwall.com
- cert-portal.siemens.com
- cert-portal.siemens.com
- lists.fedoraproject.org
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