result.append([1,matches['main'][0]['rule']]) and got messages TypeError: list indices must be integers, not str

Question

im using this code below but it doesnt work.. content of filepath available here peid.yara. full code here integrated_feature_extraction.py

def __init__(self,source,output,label):
        self.source = source
        self.output = output
        self.type = label
    #Need PEiD rules compile with yara
        self.rules= yara.compile(filepath='/home/osboxes/honeymalware/scripts/peid.yara')  
        
def check_packer(self,filepath):
        result=[]
        matches = self.rules.match(filepath)
        if matches == []:
               result.append([0,"NoPacker"])
        else:
               result.append([1,matches['main'][0]['rule']])
        return result
    
def main():    
        source_path= raw_input("Enter the path of samples (ending with /) >>  ")
        output_file= raw_input("Give file name of output file. (.csv) >>")
        label = raw_input("Enter type of sample( malware(1)|benign(0))>>")

when i run the program i get an error

Traceback (most recent call last):
  File "integrated_features_extraction.py", line 375, in <module>
    main()
  File "integrated_features_extraction.py", line 372, in main
    features.create_dataset()
  File "integrated_features_extraction.py", line 356, in create_dataset
    data = self.extract_all(filepath)
  File "integrated_features_extraction.py", line 330, in extract_all
    packer = self.check_packer(filepath)
  File "integrated_features_extraction.py", line 239, in check_packer
    result.append([1,matches['main'][0]['rule']])
TypeError: list indices must be integers, not str

i think problem occurred while executing result.append([1,matches['main'][0]['rule']]).what is wrong with the code above ??. what should i do ?? The output should be "no packer" or rulename in filepath.

Answer 1

The issue was with the change in match() method of Yara module. Earlier a dictionary was return so that was accessing using a key but now it returns a list and so there was a need to change the code.

I have written the script so I have updated the same on the GitHub project page.

 else:
        #result.append([1,matches['main'][0]['rule']])

        result.append([1,matches[0]])

Thanks, everyone for finding and resolving the issue.

Answer 2

List can be accessed using indexes, example matches[0], matches[1], matches[2] .. etc., In your program, you accessed a list using a string 'main' and 'rule', matches['main'][0]['rule'] which raises an exception for TypeError.