Maven 2.1.0+ supports server password encryption This tool lets you decrypt these passwords as long as you have access to both the settings.xml file and the settings-security.xml file.
To use it download the compiled distributable or build it from source with
./gradlew
This will produce the distribution zip file in build/distributions
usage: settings-decoder
-f,--settings <arg> location of settings.xml file.
-s,--settings-security <arg> location of settings-security.xml.