CVE-2018-19837 : Vulnerability Insights and Analysis

CVE-2018-19837 was published on December 4, 2018, and affects LibSass versions prior to 3.5.5. The vulnerability allows attackers to trigger a denial-of-service attack by exploiting a parsing issue in the eval.cpp file.

Understanding CVE-2018-19837

This CVE highlights a vulnerability in LibSass that can be exploited to cause a denial-of-service condition.

What is CVE-2018-19837?

In LibSass versions before 3.5.5, a specific parsing error in the eval.cpp file enables attackers to execute a denial-of-service attack by utilizing a specially crafted Sass file. The vulnerability stems from the incorrect interpretation of the '%' character as a modulo operator in the parser.cpp file, resulting in excessive stack consumption.

The Impact of CVE-2018-19837

The vulnerability in LibSass could lead to a denial-of-service condition, potentially disrupting services and causing system instability.

Technical Details of CVE-2018-19837

This section delves into the technical aspects of the CVE.

Vulnerability Description

The vulnerability lies in the Sass::Eval::operator()(Sass::Binary_Expression*) function within eval.cpp, allowing attackers to exhaust the stack through a malicious Sass file due to the mishandling of the '%' character as a modulo operator in parser.cpp.

Affected Systems and Versions

Product: LibSass
Vendor: N/A
Versions Affected: Prior to 3.5.5

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting a specific Sass file that triggers the incorrect parsing of the '%' character, leading to excessive stack consumption.

Mitigation and Prevention

Protecting systems from CVE-2018-19837 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update LibSass to version 3.5.5 or newer to mitigate the vulnerability.
Monitor for any unusual stack consumption that could indicate a potential attack.

Long-Term Security Practices

Regularly update software and libraries to patch known vulnerabilities.
Implement code reviews and security testing to catch parsing errors and other issues early.

Patching and Updates

Apply patches provided by LibSass promptly to address the parsing vulnerability and prevent exploitation.