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 possibility of exploiting this vulnerability is limited and can only take place during the installation phase of ESET products. Furthermore, exploitation can only succeed when Self-Defense is disabled. Affected products are: 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.
Weakness
During installation, installed file permissions are set to allow anyone to modify those files.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Endpoint_antivirus | Eset | * | 7.3 (including) |
| Endpoint_security | Eset | * | 7.3 (including) |
| File_security | Eset | * | 7.2 (including) |
| Internet_security | Eset | * | 13.2 (including) |
| Internet_security | Eset | 1294 (including) | 1294 (including) |
| Mail_security | Eset | * | 7.2 (including) |
| Nod32_antivirus | Eset | * | 7.3 (including) |
| Nod32_antivirus | Eset | * | 13.2 (including) |
| Security | Eset | * | 7.2 (including) |
| Smart_security | Eset | * | 7.3 (including) |
| Smart_security | Eset | * | 13.2 (including) |
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/1.html
- https://cwe.mitre.org/data/definitions/127.html
- https://cwe.mitre.org/data/definitions/81.html