Forge fix for log4j2 RCE with color formatting and IP filtering in console, but not logs.

README.md

Fixes the remote code execution issues with Log4j2 while keeping Forge's color scheme for console output.

Optionally filter out IP addressses so that they don't show up on a screen where you don't want them.

Based on https://www.minecraft.net/en-us/article/important-message--security-vulnerability-java-edition

IP Filtering done by blay09

log4j2-filterip.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" shutdownHook="disable">
    <filters>
        <ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CLASSDUMP" onMatch="${sys:forge.logging.marker.classdump:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
    </filters>
    <Appenders>
        <TerminalConsole name="Console">
            <PatternLayout>
                <LoggerNamePatternSelector defaultPattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [%c{2.}/%markerSimpleName]: %minecraftFormatting{%replace{%msg{nolookups}}{[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+}{xx.xx.xx.xx}}%n}">
                    <!-- don't include the full logger name for Mojang's logs since they use full class names and it's very verbose -->
                    <PatternMatch key="net.minecraft." pattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%replace{%msg{nolookups}}{[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+}{xx.xx.xx.xx}}%n}"/>
                    <PatternMatch key="com.mojang." pattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [mojang/%logger{1}]: %minecraftFormatting{%replace{%msg{nolookups}}{[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+}{xx.xx.xx.xx}}%n}"/>
                </LoggerNamePatternSelector>
            </PatternLayout>
        </TerminalConsole>
        <Queue name="ServerGuiConsole" ignoreExceptions="true">
            <PatternLayout>
                <LoggerNamePatternSelector defaultPattern="[%d{HH:mm:ss}] [%t/%level] [%c{2.}/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n">
                    <!-- don't include the full logger name for Mojang's logs since they use full class names and it's very verbose -->
                    <PatternMatch key="net.minecraft." pattern="[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%msg{nolookups}}{strip}%n"/>
                    <PatternMatch key="com.mojang." pattern="[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%msg{nolookups}}{strip}%n"/>
                </LoggerNamePatternSelector>
            </PatternLayout>
        </Queue>
        <RollingRandomAccessFile name="File" fileName="logs/latest.log" filePattern="logs/%d{yyyy-MM-dd}-%i.log.gz">
            <PatternLayout pattern="[%d{ddMMMyyyy HH:mm:ss.SSS}] [%t/%level] [%logger/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n%xEx"/>
            <Policies>
                <TimeBasedTriggeringPolicy/>
                <OnStartupTriggeringPolicy/>
            </Policies>
            <DefaultRolloverStrategy max="99" fileIndex="min"/>
        </RollingRandomAccessFile>
        <RollingRandomAccessFile name="DebugFile" fileName="logs/debug.log" filePattern="logs/debug-%i.log.gz">
            <PatternLayout pattern="[%d{ddMMMyyyy HH:mm:ss.SSS}] [%t/%level] [%logger/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n%xEx"/>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="200MB"/>
            </Policies>
            <DefaultRolloverStrategy max="5" fileIndex="min"/>
        </RollingRandomAccessFile>
    </Appenders>
    <Loggers>
        <!-- make sure mojang's logging is set to 'info' so that their LOGGER.isDebugEnabled() behavior isn't active -->
        <Logger level="${sys:forge.logging.mojang.level:-info}" name="com.mojang"/>
        <Logger level="${sys:forge.logging.mojang.level:-info}" name="net.minecraft"/>
        <Logger level="${sys:forge.logging.classtransformer.level:-info}" name="cpw.mods.modlauncher.ClassTransformer"/>
        <Root level="all">
            <filters>
                <MarkerFilter marker="NETWORK_PACKETS" onMatch="DENY" onMismatch="NEUTRAL" />
            </filters>
            <AppenderRef ref="Console" level="${sys:forge.logging.console.level:-info}"/>
            <AppenderRef ref="ServerGuiConsole" level="${sys:forge.logging.console.level:-info}"/>
            <AppenderRef ref="File" level="${sys:forge.logging.file.level:-info}"/>
            <AppenderRef ref="DebugFile" level="${sys:forge.logging.debugFile.level:-debug}"/>
        </Root>
    </Loggers>
</Configuration>

log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" shutdownHook="disable">
    <filters>
        <ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CLASSDUMP" onMatch="${sys:forge.logging.marker.classdump:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
        <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
    </filters>
    <Appenders>
        <TerminalConsole name="Console">
            <PatternLayout>
                <LoggerNamePatternSelector defaultPattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [%c{2.}/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}%n}">
                    <!-- don't include the full logger name for Mojang's logs since they use full class names and it's very verbose -->
                    <PatternMatch key="net.minecraft." pattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%msg{nolookups}}%n}"/>
                    <PatternMatch key="com.mojang." pattern="%highlight{[%d{HH:mm:ss}] [%t/%level] [mojang/%logger{1}]: %minecraftFormatting{%msg{nolookups}}%n}"/>
                </LoggerNamePatternSelector>
            </PatternLayout>
        </TerminalConsole>
        <Queue name="ServerGuiConsole" ignoreExceptions="true">
            <PatternLayout>
                <LoggerNamePatternSelector defaultPattern="[%d{HH:mm:ss}] [%t/%level] [%c{2.}/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n">
                    <!-- don't include the full logger name for Mojang's logs since they use full class names and it's very verbose -->
                    <PatternMatch key="net.minecraft." pattern="[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%msg{nolookups}}{strip}%n"/>
                    <PatternMatch key="com.mojang." pattern="[%d{HH:mm:ss}] [%t/%level] [minecraft/%logger{1}]: %minecraftFormatting{%msg{nolookups}}{strip}%n"/>
                </LoggerNamePatternSelector>
            </PatternLayout>
        </Queue>
        <RollingRandomAccessFile name="File" fileName="logs/latest.log" filePattern="logs/%d{yyyy-MM-dd}-%i.log.gz">
            <PatternLayout pattern="[%d{ddMMMyyyy HH:mm:ss.SSS}] [%t/%level] [%logger/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n%xEx"/>
            <Policies>
                <TimeBasedTriggeringPolicy/>
                <OnStartupTriggeringPolicy/>
            </Policies>
            <DefaultRolloverStrategy max="99" fileIndex="min"/>
        </RollingRandomAccessFile>
        <RollingRandomAccessFile name="DebugFile" fileName="logs/debug.log" filePattern="logs/debug-%i.log.gz">
            <PatternLayout pattern="[%d{ddMMMyyyy HH:mm:ss.SSS}] [%t/%level] [%logger/%markerSimpleName]: %minecraftFormatting{%msg{nolookups}}{strip}%n%xEx"/>
            <Policies>
                <OnStartupTriggeringPolicy/>
                <SizeBasedTriggeringPolicy size="200MB"/>
            </Policies>
            <DefaultRolloverStrategy max="5" fileIndex="min"/>
        </RollingRandomAccessFile>
    </Appenders>
    <Loggers>
        <!-- make sure mojang's logging is set to 'info' so that their LOGGER.isDebugEnabled() behavior isn't active -->
        <Logger level="${sys:forge.logging.mojang.level:-info}" name="com.mojang"/>
        <Logger level="${sys:forge.logging.mojang.level:-info}" name="net.minecraft"/>
        <Logger level="${sys:forge.logging.classtransformer.level:-info}" name="cpw.mods.modlauncher.ClassTransformer"/>
        <Root level="all">
            <filters>
                <MarkerFilter marker="NETWORK_PACKETS" onMatch="DENY" onMismatch="NEUTRAL" />
            </filters>
            <AppenderRef ref="Console" level="${sys:forge.logging.console.level:-info}"/>
            <AppenderRef ref="ServerGuiConsole" level="${sys:forge.logging.console.level:-info}"/>
            <AppenderRef ref="File" level="${sys:forge.logging.file.level:-info}"/>
            <AppenderRef ref="DebugFile" level="${sys:forge.logging.debugFile.level:-debug}"/>
        </Root>
    </Loggers>
</Configuration>