Advisory Weakness Curation

Incomplete fix for Apache Log4j 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.

Deserialization of Untrusted Data This CVE has been marked as a False Positive and has been removed. Programs using log4j-api JAR file without the log4j-core JAR file are not impacted by this vulnerability.

Incomplete fix for Apache Log4j vulnerability 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.

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') It was found that the fix to address CVE-2021-44228 in Apache Log4j 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 a denial of service (DOS) attack. Log4j restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property `log4j2.noFormatMsgLookup` to `true` do NOT mitigate this specific vulnerability. Log4j fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default.

Incomplete fix for Apache Log4j vulnerability 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.