CVE-2018-19838 : Security Advisory and Response

In versions of LibSass earlier than 3.5.5, a vulnerability exists that allows attackers to trigger a denial-of-service attack by exploiting certain functions in ast.cpp. This can be achieved by using a specially crafted sass file to exhaust the stack through recursive calls.

Understanding CVE-2018-19838

In this CVE, a flaw in LibSass versions prior to 3.5.5 can be exploited to cause a denial-of-service condition by consuming the stack excessively.

What is CVE-2018-19838?

The vulnerability in LibSass before version 3.5.5 allows attackers to launch a denial-of-service attack by using recursive calls in specific functions, leading to stack exhaustion.

The Impact of CVE-2018-19838

The vulnerability enables attackers to exploit recursive calls involving clone(), cloneChildren(), and copy() functions in ast.cpp, resulting in a denial-of-service attack by consuming the stack excessively.

Technical Details of CVE-2018-19838

This section provides detailed technical information about the CVE.

Vulnerability Description

The vulnerability in LibSass versions earlier than 3.5.5 allows attackers to trigger a denial-of-service attack by excessively consuming the stack through recursive calls in certain functions.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions prior to 3.5.5

Exploitation Mechanism

Attackers can exploit this vulnerability by utilizing recursive calls involving clone(), cloneChildren(), and copy() functions in ast.cpp, leading to excessive stack consumption.

Mitigation and Prevention

Protecting systems from CVE-2018-19838 involves taking immediate steps and implementing long-term security practices.

Immediate Steps to Take

Update LibSass to version 3.5.5 or later to mitigate the vulnerability.
Monitor for any unusual stack consumption patterns that could indicate an ongoing attack.

Long-Term Security Practices

Regularly update software and libraries to ensure the latest security patches are applied.
Conduct security audits and code reviews to identify and address potential vulnerabilities.

Patching and Updates

Ensure that all systems running LibSass are updated to version 3.5.5 or above to patch the vulnerability.