CVE-2020-1898 : Security Advisory and Response
Learn about CVE-2020-1898 affecting HHVM with uncontrolled recursion vulnerability, its impact, affected versions, and mitigation steps to prevent exploitation.
HHVM (HipHop Virtual Machine) vulnerability affecting certain versions.
Understanding CVE-2020-1898
What is CVE-2020-1898?
The vulnerability in the fb_unserialize function allowed for uncontrolled recursion leading to stack exhaustion in HHVM.
The Impact of CVE-2020-1898
This issue could be exploited by a maliciously crafted string to cause denial of service or possibly execute arbitrary code.
Technical Details of CVE-2020-1898
Vulnerability Description
The fb_unserialize function lacked depth limits, enabling recursive deserialization, impacting HHVM versions prior to 4.32.3 and between 4.33.0 to 4.62.0.
Affected Systems and Versions
- Products: HHVM
- Vendor: Facebook
- Affected Versions: 4.32.3, 4.33.0 to 4.56.0, 4.57.0, 4.58.0, 4.58.1, 4.59.0, 4.60.0, 4.61.0, 4.62.0
Exploitation Mechanism
Maliciously constructed strings could trigger uncontrolled recursion in the deserialization process, leading to stack exhaustion.
Mitigation and Prevention
Immediate Steps to Take
- Apply security updates provided by Facebook promptly.
- Implement input validation mechanisms to prevent malicious string inputs.
Long-Term Security Practices
- Regularly update software and security patches.
- Conduct security audits to identify vulnerabilities.
- Train developers on secure coding practices.
Patching and Updates
- Facebook has released patches for affected versions, ensuring depth limits for deserialization are enforced to prevent recursion.