CVE-2018-20821 Explained : Impact and Mitigation

LibSass through version 3.5.5 is vulnerable to a denial-of-service attack due to uncontrolled recursion in the parsing component. Attackers can exploit this vulnerability to trigger a denial-of-service attack by manipulating the Sass::Parser::parse_css_variable_value function in parser.cpp.

Understanding CVE-2018-20821

This CVE involves a vulnerability in the parsing component of LibSass that allows attackers to initiate a denial-of-service attack.

What is CVE-2018-20821?

The vulnerability in LibSass up to version 3.5.5 enables attackers to exploit uncontrolled recursion in the Sass::Parser::parse_css_variable_value function, leading to a denial-of-service attack.

The Impact of CVE-2018-20821

The vulnerability can be exploited by attackers to cause a denial-of-service condition on systems running the affected versions of LibSass.

Technical Details of CVE-2018-20821

This section provides detailed technical information about the CVE.

Vulnerability Description

The parsing component in LibSass through version 3.5.5 allows attackers to trigger a denial-of-service attack through uncontrolled recursion in the Sass::Parser::parse_css_variable_value function in parser.cpp.

Affected Systems and Versions

Product: LibSass
Vendor: N/A
Versions affected: Up to version 3.5.5

Exploitation Mechanism

Attackers can exploit the vulnerability by manipulating the Sass::Parser::parse_css_variable_value function in parser.cpp to trigger uncontrolled recursion, leading to a denial-of-service attack.

Mitigation and Prevention

Protecting systems from CVE-2018-20821 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update LibSass to a patched version that addresses the vulnerability.
Monitor for any unusual activity that could indicate a denial-of-service attack.

Long-Term Security Practices

Regularly update software and libraries to mitigate known vulnerabilities.
Implement network security measures to detect and prevent denial-of-service attacks.
Conduct security assessments and audits to identify and address potential vulnerabilities.
Educate users and administrators about best security practices to prevent exploitation.
Stay informed about security advisories and patches released by software vendors.

Patching and Updates

Ensure that all systems running LibSass are updated to a version that includes the necessary patches to mitigate the vulnerability.