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…
apache·CWE-917·Published 2021-12-14
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, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${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.
# Impact The fix to address [CVE-2021-44228](https://nvd.nist.gov/vuln/detail/CVE-2021-44228) in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allow 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, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a remote code execution (RCE) attack. ## Affected packages Only the `org.apache.logging.log4j:log4j-core` package is directly affected by this vulnerability. The `org.apache.logging.log4j:log4j-api` should be kept at the same version as the `org.apache.logging.log4j:log4j-core` package to ensure compatability if in use. # Mitigation Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default. This issue can be mitigated in prior releases (< 2.16.0) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class). Log4j 2.15.0 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property `log4j2.formatMsgNoLookups` to `true` do NOT mitigate this specific vulnerability.
# Impact The fix to address [CVE-2021-44228](https://nvd.nist.gov/vuln/detail/CVE-2021-44228) in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allow attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in a remote code execution (RCE) attack. ## Affected packages Only the `org.apache.logging.log4j:log4j-core` package is directly affected by this vulnerability. The `org.apache.logging.log4j:log4j-api` should be kept at the same version as the `org.apache.logging.log4j:log4j-core` package to ensure compatability if in use. # Mitigation Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default. This issue can be mitigated in prior releases (< 2.16.0) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class). Log4j 2.15.0 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property `log4j2.formatMsgNoLookups` to `true` do NOT mitigate this specific vulnerability.
Se descubrió que la corrección para abordar CVE-2021-44228 en Apache Log4j versiones 2.15.0 estaba incompleta en ciertas configuraciones no predeterminadas. Esto podría permitir a los atacantes con control sobre los datos de entrada de Thread Context Map (MDC) cuando la configuración de registro utiliza un Pattern Layout no predeterminado con un Context Lookup (por ejemplo, $${ctx:loginId}) o un Thread Context Map pattern (%X, %mdc, o %MDC) para elaborar datos de entrada maliciosos utilizando un patrón JNDI Lookup que resulta en una fuga de información y ejecución de código remoto en algunos entornos y ejecución de código local en todos los entornos. Log4j versiones 2.16.0 (Java 8) y 2.12.2 (Java 7) solucionan este problema eliminando el soporte para los patrones de búsqueda de mensajes y deshabilitando la funcionalidad JNDI por defecto
| Version | Type | Source | Base | Exp | Impact | Vector |
|---|---|---|---|---|---|---|
| 2.0 | Primary | NVD | 5.1 | 4.9 | 6.4 | AV:N/AC:H/Au:N/C:P/I:P/A:P |
| 3.1 | Primary | cve.org | 9.0 | — | — | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | Primary | cve.org | 9.0 | — | — | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | Primary | NVD | 9.0 | 2.2 | 6.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | Secondary | GHSA | 9.0 | — | — | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H |
| 3.1 | Secondary | NVD | 9.0 | 2.2 | 6.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |