CVE-2020-1893 : Security Advisory and Response

An insufficient boundary check vulnerability affecting HHVM versions leading to potential Denial of Service (DOS).

Understanding CVE-2020-1893

What is CVE-2020-1893?

The vulnerability in HHVM's JSON decoding can result in out of bounds memory reads, potentially causing DOS.

The Impact of CVE-2020-1893

Exploitation can lead to DOS attacks.
Versions from 4.45.0 to 4.8.7 are affected.

Technical Details of CVE-2020-1893

Vulnerability Description

Insufficient boundary checks when decoding JSON can trigger out of bounds memory reads.

Affected Systems and Versions

HHVM versions 4.45.0 to 4.8.7 are impacted.

Exploitation Mechanism

Attackers can exploit the boundary check issue to perform DOS attacks.

Mitigation and Prevention

Immediate Steps to Take

Update HHVM to the latest non-vulnerable version.
Monitor for unusual service behavior that may indicate a DOS attack.
Ensure all network-facing services are properly firewalled.

Long-Term Security Practices

Regularly update and patch software to mitigate known vulnerabilities.
Implement network intrusion detection systems to identify and block potential attacks.

Patching and Updates

Apply vendor-released patches promptly to fix the vulnerability.