Affected Version(s)

Solution

Trend Micro has released the following solutions to address the issue:

These are the minimum recommended version(s) of the patches and/or builds required to address the issue. Trend Micro highly encourages customers to obtain the latest version of the product if there is a newer one available than the one listed in this bulletin.

Please note:  both server and clients will need to apply the update to resolve the latest vulnerabilities listed in this bulletin.

Customers are encouraged to visit Trend Micro’s Download Center to obtain prerequisite software (such as Service Packs) before applying any of the solutions above.

Vulnerability Details

CVE-2021-25250 and CVE-2021-25253:  Improper Access Control Privilege Escalation Vulnerabilities 
CVSSv3: 7.8: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Improper access control vulnerabilities in Trend Micro OfficeScan XG SP1 could allow a local attacker to escalate privileges on affected installations.
Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

CVE-2021-28645:  Incorrect Permission Assignment Privilege Escalation Vulnerability 
CVSSv3: 7.8: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
An incorrect permission assignment vulnerability in Trend Micro OfficeScan XG SP1 could allow a local attacker to escalate privileges on affected installations.
Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

CVE-2021-28646:  Insecure File Permissions Vulnerability 
CVSSv3: 4.7: AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
An insecure file permissions vulnerability in Trend Micro OfficeScan XG SP1 could allow a local attacker to take control of a specific log file on affected installations.

Mitigating Factors

Exploiting these type of vulnerabilities generally require that an attacker has access (physical or remote) to a vulnerable machine. In addition to timely application of patches and updated solutions, customers are also advised to review remote access to critical systems and ensure policies and perimeter security is up-to-date.

However, even though an exploit may require several specific conditions to be met, Trend Micro strongly encourages customers to update to the latest builds as soon as possible.

Acknowledgement

Trend Micro would like to thank the following individuals for responsibly disclosing these issues and working with Trend Micro to help protect our customers:

• @Kharosx0 working with Trend Micro's Zero Day Initiative
• • Lynn and Lays (_@L4ys) working with Trend Micro's Zero Day Initiative
• Richard Davy of ECSC Group

External Reference(s)

• ZDI-CAN-11951
• ZDI-CAN-12148
• ZDI-CAN-12147