// June 8th, 2010 // No Comments » // Projects
Name: Spiderpig
Category: PDF Fuzzer
Author/Owner: cons0ul
Download URL: http://code.google.com/p/spiderpig-pdffuzzer/
Description:
Adobe and others uses javascript in pdfs to enhance standard workflow for example connecting to database ,spell checking,printing n viewing etc..when we open pdf in reader,it executes this javascript code(ya we all know that). so goal of spiderpig is to find bugs in pdf reader’s javascript engine. spiderpig reads methods prototype from an input file and creates pdf file. Most of the pdf fuzzers which are available on internet are file format fuzzers which tries to fuzz the adobe’s file format implementation.I didnt find one fuzzer which fuzzes adobe’s javascript imeplementaiton,so here we have spiderpig a javascript fuzzer for pdf file format which tries to screw up pdf reader using javascript methods.
spiderpig uses bruteforce method to abuse reader, it creates methods using all range of evil parameters.If you are aware of fuzzers like axman and dranzer,you know what I am talking about.spiderpig reads methods prototype from an input file and creates stream of javascript code and then this stream is then added into pdf file using makepdf module.
An example Input file is in spiderpig’s directory named as test.proto .
test.proto contains methods prototypes with (object/namespace scope)which helps spiderpig to understand the method and its parameters.Add prototypes of methods which are you going to test in this file.Each new method must be written on new line. For example if you want to test methods [alert] and [beep] methods from [app] object you can write prototype as follows
app.alert(nIcon,nType,cTitle,oDoc,oCheckbox)
app.beep(nType)
it will create 2 pdfs 1 for app.alert(app.alert.pdf) and another for app.beep(app.beep.pdf).
>>/parameters type:
spiderpig understands type of parameter(strin,number,boolean,object) by reading
the first character of parameter written in methods prototype.
spiderpig understands,
n for numbers
b for boolean
o for object
c for string
so while writing prototype add them as shown in above example.
spiderpig uses javascript console(console.println and console.show) functionality provided by adobe reader to create log.so you can see which method call is being called.see following screenshot
Here are the steps to use spiderpig:
1>download spiderpig
2>extract it to folder
3>create a file for example test.proto in this file write methods prototypes
4>open comand prompt and goto the folder.
4>type python sp.py <folder-path> test.proto
where <folder-path> is exsisting folder in which pdfs will be created.
5>open pdf reader.
6>attach debugger.
7>open pdf file in reader.
8>do reverse engineering