Java Support¶
angr
also supports symbolically executing Java code and Android apps! This
also includes Android apps using a combination of compiled Java and native
(C/C++) code.
Warning
Java support is experimental! Contribution from the community is highly encouraged! Pull requests are very welcomed!
We implemented Java support by lifting the compiled Java code, both Java and DEX
bytecode, leveraging our Soot Python wrapper: pysoot. pysoot
extracts a fully serializable
interface from Android apps and Java code (unfortunately, as of now, it only
works on Linux). For every class of the generated IR (for instance,
SootMethod
), you can nicely print its instructions (in a format similar to
Soot
shimple
) using print()
or str()
.
We then leverage the generated IR in a new angr engine able to run code in Soot IR: angr/engines/soot/engine.py. This engine is also able to automatically switch to executing native code if the Java code calls any native method using the JNI interface.
Together with the symbolic execution, we also implemented some basic static analysis, specifically a basic CFG reconstruction analysis. Moreover, we added support for string constraint solving, modifying claripy and using the CVC4 solver.
How to install¶
Enabling Java support requires few more steps than typical angr installation. Assuming you installed angr-dev, activate the virtualenv and run:
pip install -e ./claripy[cvc4-solver]
./setup.sh pysoot
Analyzing Android apps.¶
Analyzing Android apps (.APK
files, containing Java code compiled to the
DEX
format) requires the Android SDK. Typically, it is installed in
<HOME>/Android/SDK/platforms/platform-XX/android.jar
, where XX
is the
Android SDK version used by the app you want to analyze (you may want to install
all the platforms required by the Android apps you want to analyze).
Examples¶
There are multiple examples available:
Easy Java crackmes: java_crackme1, java_simple3, java_simple4
A more complex example (solving a CTF challenge): ictf2017_javaisnotfun, blogpost
Symbolically executing an Android app (using a mix of Java and native code): java_androidnative1
Many other low-level tests: test_java