CVE-2020-26941 Explained : Impact and Mitigation

A local (authenticated) low-privileged user can exploit a behavior in an ESET installer to achieve arbitrary file overwrite (deletion) of any file via a symlink, due to insecure permissions. The vulnerability is limited to the installation phase of ESET products and requires Self-Defense to be disabled. Various ESET products and versions are affected.

Understanding CVE-2020-26941

This CVE describes a local privilege escalation vulnerability in ESET products that allows a low-privileged user to overwrite or delete files during the installation process.

What is CVE-2020-26941?

CVE-2020-26941 is a security vulnerability that enables a local attacker with low privileges to manipulate files through a symlink during the installation of ESET products, leading to arbitrary file overwrite or deletion.

The Impact of CVE-2020-26941

The exploitation of this vulnerability can result in unauthorized file modifications or deletions during the installation of affected ESET products, potentially compromising system integrity and security.

Technical Details of CVE-2020-26941

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises from insecure permissions in the ESET installer, allowing a local attacker to create symlinks and overwrite or delete arbitrary files during product installation.

Affected Systems and Versions

The following ESET products and versions are impacted by CVE-2020-26941:

ESET NOD32 Antivirus, ESET Internet Security, ESET Smart Security, ESET Smart Security Premium versions 13.2 and lower
ESET Endpoint Antivirus, ESET Endpoint Security, ESET NOD32 Antivirus Business Edition, ESET Smart Security Business Edition versions 7.3 and lower
ESET File Security for Microsoft Windows Server, ESET Mail Security for Microsoft Exchange Server, ESET Mail Security for IBM Domino, ESET Security for Kerio, ESET Security for Microsoft SharePoint Server versions 7.2 and lower

Exploitation Mechanism

The vulnerability can be exploited by a local attacker with low privileges during the installation phase of ESET products when Self-Defense is disabled, using symlinks to overwrite or delete files.

Mitigation and Prevention

Protecting systems from CVE-2020-26941 requires immediate actions and long-term security practices.

Immediate Steps to Take

Ensure Self-Defense is enabled in ESET products to prevent exploitation during installation
Regularly monitor file system changes for any unauthorized modifications

Long-Term Security Practices

Implement the principle of least privilege to restrict user permissions
Conduct regular security audits and vulnerability assessments to identify and address potential risks

Patching and Updates

Apply security patches and updates provided by ESET to address the vulnerability and enhance system security