NRS is a set of Python librairies used to unpack and analysis NSIS installer's data. It also feature an IDA plugin used to disassembly the NSIS Script of an installer.
NRS is available through Pypi or this repositoy. To use with IDA, the native module must be build in 32 bits since IDA use its own 32 bits Python runtime on x64_86 systems.
It is recommended to use IDAPython-virtualenv to manage Python dependancies in IDA.
Change working directory to IDA root directory: cd $IDA_DIR
To setup virtualenv: virtualenv -p python2 venv && source venv/bin/activate.
Install nrs from Pypi and build in 32 bits: CFLAGS=-m32 LDFLAGS=-m32 pip install nrs.
It can also be installed from the git repository: CFLAGS=-m32 LDFLAGS=-m32 pip install -e $PATH_TO_LOCAL_REPO.
Create symbolic links from NRS modules to IDA folders: python -c 'import nrs.ida;nrs.ida.install(). The venv folder must be in the IDA folder or you must pass the ida folder path to the nrs.ida.install function.
Open IDA and load any NSIS installer!
If you have errors about nrs modules not found, ensure you run IDA from the Python venv.
A simple way is simply to run it from command line with your virtualenv activated:
$ source venv/bin/activate
$ ./idaq