extract-tls-secrets

Decrypt HTTPS/TLS connections on-the-fly. Extract the shared secrets from secure TLS connections for use with Wireshark. Attach to a Java process on either side of the connection to start decrypting.

Usage

Download from extract-tls-secrets-4.0.0.jar. Then attach to a Java process in one of two ways:

Attach on startup

Add a startup argument to the JVM options: -javaagent:<path to jar>/extract-tls-secrets-4.0.0.jar=<path to secrets log file>

For example to launch an application from a jar file run:

java -javaagent:~/Downloads/extract-tls-secrets-4.0.0.jar=/tmp/secrets.log -jar MyApp.jar

To launch in Tomcat add the parameter to CATALINA_OPTS:

CATALINA_OPTS=-javaagent:~/Downloads/extract-tls-secrets-4.0.0.jar=/tmp/secrets.log bin/catalina.sh run

Attach to a running process

Attaching to an existing Java process requires a JDK install with JAVA_HOME pointing to it.

To list the available process IDs run:

java -jar ~/Downloads/extract-tls-secrets-4.0.0.jar list

Next attach to the process by executing:

java -jar ~/Downloads/extract-tls-secrets-4.0.0.jar attach <pid> /tmp/secrets.log

If no secrets file path is given, secrets are written to tls-master-secrets.txt in the current working directory. Relative paths are resolved against the directory where the command is run, not the target process's working directory.

Detach from a running process

To stop secrets logging without restarting the target process:

java -jar ~/Downloads/extract-tls-secrets-4.0.0.jar detach <pid>

Detaching is safe: the target process continues running normally and the agent can be re-attached later to resume logging.

Decrypt the capture in Wireshark

To decrypt the capture you need to let Wireshark know where the secrets file is. Configure the path in Preferences > Protocols > TLS > (Pre)-Master-Secret log filename.

Alternatively start Wireshark with:

wireshark -o tls.keylog_file:/tmp/secrets.log

The packets will be decrypted in real-time.

For a step-by-step tutorial of using the secrets log file (SSLKEYLOGFILE as referenced usually) refer to the Peter Wu's Debugging TLS issues with Wireshark presentation. Even more information can be found at the Wireshark TLS page.

Requirements

Requires at least Oracle/OpenJDK Java 6. Supports the following TLS providers:

• Oracle/OpenJDK built-in JSSE (all supported Java versions)
• IBM JSSE2 (ibmjava:8)
• Bouncy Castle JSSE (bcjsse 1.57+)

Conscrypt is not supported.

Building

git clone https://github.com/neykov/extract-tls-secrets.git
cd extract-tls-secrets
mvn clean package

Running the integration tests requires Docker to be installed on the system:

mvn verify

Troubleshooting

If you get an empty window after selecting "Follow/TLS Stream" from the context menu or are not seeing HTTP protocol packets in the packet list then you can fix this by either:

• Save the capture as a file and open it again
• In the Wireshark settings in "Procotols/TLS" toggle "Reassemble TLS Application Data spanning multiple SSL records". The exact state of the checkbox doesn't matter, but it will force a reload which will force proper decryption of the packets.

The bug seems to be related to the UI side of wireshark as the TLS debug logs show the message successfully being decrypted.

Reports of the problem:

• https://ask.wireshark.org/questions/33879/ssl-decrypt-shows-ok-in-ssl-debug-file-but-not-in-wireshark
• https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=9154

If "Follow/TLS Stream" is not enabled the server is probably on a non-standard port so Wireshark can't infer that the packets contain TLS traffic. To hint it that it should be decoding the packets as TLS right click on any of the packets to open the context menu, select "Decode As" and add the server port, select "TLS" protocol in the "Current" column. If it's still not able to decrypt try the same by saving the capture in a file and re-opening it.

Warnings during agent loading

EnableDynamicAgentLoading

Starting with Java 21, upon attaching the agent, the target process will print the following warning:

WARNING: A Java agent has been loaded dynamically WARNING: If a serviceability tool is in use, please run with -XX:+EnableDynamicAgentLoading to hide this warning WARNING: If a serviceability tool is not in use, please run with -Djdk.instrument.traceUsage for more information WARNING: Dynamic loading of agents will be disallowed by default in a future release

The warning is informational and does not lead to broken functionality. To suppress the warning add -XX:+EnableDynamicAgentLoading to the startup options of the target process.

If the target process has disabled dynamic agent loading by setting -XX:-EnableDynamicAgentLoading at startup, then attaching will fail with:

Failed to load agent library: Dynamic agent loading is not enabled. Use -XX:+EnableDynamicAgentLoading to launch target VM.

More details can be found in JEP 451.

Class path has been appended

When the agent is loaded in the target process, the JVM will print the following warning:

OpenJDK 64-Bit Server VM warning: Sharing is only supported for boot loader classes because bootstrap classpath has been appended.

This is expected behaviour since the agent modifies the bootstrap classpath during initialisation. The warning exists since Java 10 when the classpath data sharing functionaity has been implemented.