CVE-2022-24859: PyPDF2 - Infinite Loop Vulnerability

Background

PyPDF2 is a Python library for working with PDF files. It provides functionality to read, write, and manipulate PDF documents. The library is widely used for tasks such as extracting text, merging multiple PDFs, and adding annotations. PyPDF2 is vulnerable to an infinite loop issue that can be triggered by manipulating inline images in a PDF file.

Vulnerability Detail

The vulnerability in PyPDF2 allows an attacker to craft a malicious PDF file that can cause an infinite loop when processed by the library. If a PyPDF2 user attempts to extract the contents of the PDF using the PdfFileReader class and iterates over the pages, an infinite loop can occur if the page contains manipulated inline images. This can lead to resource exhaustion and denial of service. The vulnerability has a CVSS score of 6.2 (Moderate).

pip install --upgrade "pypdf2==3.0.1"

pip install --upgrade "pypdf2==1.27.5"

Workaround

If updating PyPDF2 is not immediately possible, a workaround is to avoid processing PDF files with manipulated inline images. This can be achieved by checking the contents of each page before processing it. Here is an example of how to implement this workaround in Python:

from PyPDF2 import PdfFileReader, ContentStream

def process_pdf(file_path):
    reader = PdfFileReader(file_path, strict=False)
    for page in reader.pages:
        contents = page.getContents()
        if not contains_manipulated_images(contents):
            ContentStream(contents, reader)


def contains_manipulated_images(contents):
    # Check if the contents contain manipulated inline images
    # Return True if manipulated images are found, False otherwise
    pass

In this example, the contains_manipulated_images function should be implemented to analyze the contents of a page and determine if it contains manipulated inline images. If no manipulated images are found, the page can be processed safely.

Conclusion

The PyPDF2 library is vulnerable to an infinite loop issue that can be triggered by manipulated inline images in a PDF file. To mitigate this vulnerability, it is recommended to update PyPDF2 to version 1.27.5 or later. If immediate updating is not possible, a workaround is available by checking the contents of each page for manipulated images. For further assistance and support on vulnerability remediation, please contact DevNack.com.

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