RubyGems Symbolic Link Directory Traversal Vulnerability [CVE-2019-8320]

CVE Number – CVE-2019-8320

A vulnerability in RubyGems could allow an unauthenticated, remote attacker to modify file locations on a targeted system. The vulnerability is due to the improper handling of symlinks by the affected software. An attacker could exploit this vulnerability by submitting a malicious gem to the targeted system. A successful exploit could allow the attacker to use directory traversal techniques to delete arbitrary file locations on the targeted system.Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available. RubyGems confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, the attacker must send a gem that submits malicious input to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.

Safeguards

• Administrators are advised to apply the appropriate updates.Administrators are advised to allow only trusted users to have network access.Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.Administrators can help protect affected systems from external attacks by using a solid firewall strategy.Administrators are advised to monitor affected systems.

Vendor Announcements

• RubyGems has released a security advisory at the following link: CVE-2019-8320: Delete directory using symlink when decompressing tar

Fixed Software

• RubyGems has released software updates at the following link: RubyGems Releases