CVE-2023-36464 : Exploit Details and Defense Strategies

Understanding CVE-2023-36464

This CVE record pertains to an 'Infinite Loop' vulnerability in pypdf, a pure-python PDF library.

What is CVE-2023-36464?

pypdf allows for a crafted PDF to trigger an infinite loop when executing '__parse_content_stream', potentially leading to denial of service due to the high impact on availability.

The Impact of CVE-2023-36464

The vulnerability affects versions of pypdf prior to 3.90 and PyPDF2 versions 2.2.0 and above, making systems vulnerable to potential denial of service attacks.

Technical Details of CVE-2023-36464

This section outlines the specific technical aspects of the vulnerability.

Vulnerability Description

An attacker can create a PDF that exploits the '__parse_content_stream' function, causing an infinite loop that can be triggered when extracting text from the PDF.

Affected Systems and Versions

Vendor: py-pdf
Product: pypdf
Versions Affected:
pypdf: < 3.90 (affected)
PyPDF2: >= 2.2.0 (affected)

Exploitation Mechanism

The vulnerability arises from a flaw introduced in pull request #969 and was subsequently addressed in pull request #1828. Users are advised to upgrade their software to prevent exploitation.

Mitigation and Prevention

Learn how to protect your systems and ensure long-term security measures are in place.

Immediate Steps to Take

Upgrade to the latest version of pypdf or PyPDF2. For users unable to update, a temporary fix involves modifying the line in 'pypdf/generic/_data_structures.py'.

Long-Term Security Practices

Implement regular software updates, conduct security assessments, and monitor for vulnerabilities.

Patching and Updates

Stay informed about security patches and updates released by the py-pdf project.