CVE-2017-11626 Explained : Impact and Mitigation

QPDF 6.0.0 contained a vulnerability involving stack consumption that could lead to a denial of service when exploited by malicious actors using a specifically crafted file.

Understanding CVE-2017-11626

This CVE entry describes a vulnerability in the QPDF library that could result in an infinite loop scenario.

What is CVE-2017-11626?

The vulnerability in QPDF 6.0.0 allows attackers to trigger a denial of service by exploiting a stack-consumption issue.
The specific vulnerability is linked to the QPDFTokenizer::resolveLiteral function in QPDFTokenizer.cc.
The issue arises after four consecutive calls to QPDFObjectHandle::parseInternal, potentially causing an infinite loop.

The Impact of CVE-2017-11626

Malicious actors can exploit this vulnerability by using a specially crafted file, leading to a denial of service.
The vulnerability affects the availability of systems utilizing the QPDF library.

Technical Details of CVE-2017-11626

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability involves stack consumption in libqpdf in QPDF 6.0.0.
It allows attackers to cause a denial of service by exploiting the QPDFTokenizer::resolveLiteral function.

Affected Systems and Versions

Product: N/A
Vendor: N/A
Version: N/A

Exploitation Mechanism

Attackers can exploit the vulnerability by using a specifically crafted file to trigger an infinite loop scenario.

Mitigation and Prevention

Here are the steps to mitigate and prevent exploitation of CVE-2017-11626.

Immediate Steps to Take

Update QPDF to a patched version that addresses the stack-consumption vulnerability.
Implement file input validation to prevent the execution of malicious files.

Long-Term Security Practices

Regularly monitor and update software libraries to address known vulnerabilities.
Conduct security assessments and code reviews to identify and mitigate similar issues.

Patching and Updates

Stay informed about security advisories and patches released by QPDF.
Apply security updates promptly to protect systems from potential exploitation.