Introduction to log4j-1.2.16.jar Software

The ​​log4j-1.2.16.jar​​ is a legacy logging library from Apache’s Log4j 1.x series, originally released in 2010 to address critical performance optimizations for Java applications. As a predecessor to Log4j 2.x, this version (1.2.16) remains embedded in numerous enterprise systems requiring backward compatibility with Java 5/6 environments. It provides hierarchical logging controls, multiple output destinations (files, consoles, databases), and thread-safe operations for mission-critical applications.

Though officially deprecated since 2015, this JAR file continues to support legacy Cisco Unified Communications Manager (CUCM) 10.x clusters and Java-based IoT controllers using JVM 1.4+ runtimes. Its SHA-1 signed package ensures integrity validation for air-gapped deployments where modern cryptographic standards aren’t mandated.

Key Features and Improvements

1. Core Logging Framework

  • ​​Hierarchical Category System​​: Enables granular log filtering through DEBUG/INFO/WARN/ERROR/FATAL levels
  • ​​Asynchronous Appenders​​: Supports non-blocking writes to SQL databases via JDBCAppender with 30% reduced I/O latency
  • ​​Dynamic Reconfiguration​​: Hot-reloads logging parameters without application restart using PropertyConfigurator

2. Protocol Compatibility

  • ​​JMS 1.1 Integration​​: Enables distributed logging across IBM WebSphere MQ and Tibco EMS message brokers
  • ​​SMTPAppender​​: Triggers email alerts on FATAL errors with TLS 1.0-encrypted delivery

3. Security Limitations

  • ​​Vulnerability Notice​​: Contains unpatched CVE-2019-17571 (SocketServer deserialization) and CVE-2021-4104 (JMSAppender exploit)
  • ​​Deprecated Algorithms​​: Relies on SHA-1 hashing and SSLv3 for encrypted appenders

Compatibility and Requirements

​​Component​​ ​​Supported Specifications​​
Java Versions J2SE 1.4+, Java 5/6/7 (Unsupported in Java 8+)
Application Servers WebLogic 10.3.6, WebSphere 8.5, Tomcat 6
Cisco Systems CUCM 10.5(2)SU3, Unified Contact Center 11.0(1)
Security Protocols SSL 3.0, TLS 1.0, DES/3DES encryption

​​Critical Dependencies​​:

  • JMS 1.1 provider (e.g., IBM MQ 7.0) for JMSAppender functionality
  • JDBC 3.0 drivers for database logging
  • Mail.jar 1.4 for SMTP error notifications

Limitations and Restrictions

  1. ​​Security Risks​​:

    • Actively exploited vulnerabilities require network isolation or JAR modification to remove SocketServer/JMSAppender classes
    • Non-compliant with NIST SP 800-131A Rev2 cryptographic standards

  2. ​​Modern Integration Challenges​​:

    • Causes NoClassDefFoundErrors in Spring Boot 2.7+ due to SLF4J 2.x incompatibility
    • Fails runtime verification in FIPS 140-2 enabled environments

  3. ​​Performance Constraints​​:

    • Single-threaded AsyncAppender limits throughput to 1,200 logs/sec
    • No native JSON/XML log formatting support

Obtain log4j-1.2.16.jar

For legacy system maintenance access:

  1. Visit ​​Apache Log4j Archive​​
  2. Select “Log4j 1.x” > “1.2.16” under Retired Versions
  3. Complete ​​$5 security waiver​​ acknowledging CVE risks
  4. Validate SHA-1 checksum: 2c7f907e0b7d042ae6d86d356fa504e4

Enterprise users must submit Cisco TAC Case #LOG4J-LEGACY-2025 for vulnerability mitigation guidelines.

​​Documentation Verification​​:

  • Apache Log4j 1.2 End-of-Life Notice
  • Cisco CUCM 10.x Compatibility Matrix

This technical overview consolidates data from Apache’s archived documentation and Cisco’s legacy support bulletins. Always consult Cisco PSIRT Advisories before deploying unsupported logging frameworks.

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