Frida Tracing Discovery

Frida Tracing Discovery

Use this skill when the target API, class, symbol, or call path is unknown.

Start Broad, Then Narrow

1. Prove the behavior happens without Frida.
2. Choose the highest-signal boundary: network, crypto, file, IPC, WebView, class loading, native library loading, or UI action.
3. Trace or enumerate around that boundary.
4. Add stack traces to identify app-owned callers.
5. Replace broad probes with narrow hooks.

CLI Tracing

frida-trace -U -f com.example.app -j 'java.net.URL!*' --no-pause
frida-trace -U -f com.example.app -i 'open' -i 'connect' --no-pause
frida-trace -U -n target -m 'Module!*pattern*'

Treat generated handlers as temporary discovery artifacts, then move proven logic into a reviewed script.

Android Discovery

Java.perform(() => {
  const groups = Java.enumerateMethods("*crypto*!*/isu");
  console.log(JSON.stringify(groups, null, 2));
});

Class loader check:

Java.perform(() => {
  Java.enumerateClassLoaders({
    onMatch(loader) {
      try {
        Java.classFactory.loader = loader;
        Java.use("com.example.Target");
        console.log("loader", loader);
      } catch (_) {}
    },
    onComplete() {}
  });
});

Native Discovery

const mod = Process.getModuleByName("libtarget.so");
for (const e of mod.enumerateExports()) {
  if (e.name.includes("SSL") || e.name.includes("crypto")) console.log(e.name, e.address);
}

Backtrace on a generic boundary:

Interceptor.attach(Module.getGlobalExportByName("open"), {
  onEnter(args) {
    console.log(args[0].readUtf8String());
    console.log(Thread.backtrace(this.context, Backtracer.ACCURATE)
      .map(DebugSymbol.fromAddress).join("\n"));
  }
});

References

Read references/discovery-patterns.md for target-specific trace ladders.