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Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')


Severity High
Score 10/10


Apache Log4j2 2.0-beta9 through 2.12.1 (excluding 2.3.1) and 2.13.0 through 2.14.1 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 (for users requiring Java 8 or later), 2.12.2 (for Java 7 users), and 2.3.1 (for Java 6 users) 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. ### How to remediate the Log4j RCE vulnerability? ### The easiest and most recommended way to remediate this vulnerability is to [update to log4j version 2.17.0 or later]( If updating the package is an issue, you may remove the JndiLookup class from the classpath. The command to perform such action is: `zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class`.

  • LOW
  • HIGH
  • NONE
  • NONE
  • HIGH
  • HIGH

CWE-74 - Injection

Listed as the number one web application security risk on the 'OWASP Top Ten', injection attacks are widespread and dangerous, especially in legacy applications. Injection attacks are a class of vulnerabilities in which an attacker injects untrusted data into a web application that gets processed by an interpreter, altering the program's execution. This can result in data loss/theft, loss of data integrity, denial of service, and even compromising the entire system.

Advisory Timeline

  • Published