CVE-2020-5211 Explained : Impact and Mitigation

NetHack AUTOCOMPLETE configuration file option is subject to a buffer overflow.

Understanding CVE-2020-5211

In NetHack before 3.6.5, an invalid extended command in the AUTOCOMPLETE configuration file option can lead to a buffer overflow, potentially causing a crash or enabling remote code execution/privilege escalation.

What is CVE-2020-5211?

NetHack before version 3.6.5 is vulnerable to a buffer overflow due to an invalid extended command in the AUTOCOMPLETE configuration file option.
The vulnerability impacts systems with NetHack installed suid/sgid and shared systems allowing user-uploaded configuration files.

The Impact of CVE-2020-5211

CVSS Score: 5 (Medium)
Attack Vector: Local
Attack Complexity: High
Privileges Required: Low
User Interaction: Required
Scope: Changed
Confidentiality, Integrity, Availability Impact: Low

Technical Details of CVE-2020-5211

Vulnerability Description

The issue arises from an invalid extended command in the AUTOCOMPLETE configuration file option, leading to a buffer overflow.

Affected Systems and Versions

Affected Product: NetHack
Vendor: NetHack
Vulnerable Versions: < 3.6.5

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting a malicious configuration file with an invalid extended command, triggering the buffer overflow.

Mitigation and Prevention

Immediate Steps to Take

Upgrade NetHack to version 3.6.5 to mitigate the vulnerability.

Long-Term Security Practices

Avoid running NetHack with elevated privileges unless necessary.
Restrict user permissions on shared systems to prevent unauthorized configuration file uploads.

Patching and Updates

Regularly check for security updates and apply patches promptly.