Acronis backup software contains multiple privilege escalation vulnerabilities

Overview

Acronis True Image, Cyber Backup, and Cyber Protection all contain privilege escalation vulnerabilities, which can allow an unprivileged Windows user to be able to run arbitrary code with SYSTEM privileges.

Description

CVE-2020-10138

Acronis Cyber Backup 12.5 and Cyber Protect 15 include an OpenSSL component that specifies an OPENSSLDIR variable as a subdirectory within C:\jenkins_agent\. Acronis Cyber Backup and Cyber Protect contain a privileged service that uses this OpenSSL component. Because unprivileged Windows users can create subdirectories off of the system root, a user can create the appropriate path to a specially-crafted openssl.cnf file to achieve arbitrary code execution with SYSTEM privileges.

CVE-2020-10139

Acronis True Image 2021 includes an OpenSSL component that specifies an OPENSSLDIR variable as a subdirectory within C:\jenkins_agent\. Acronis True Image contains a privileged service that uses this OpenSSL component. Because unprivileged Windows users can create subdirectories off of the system root, a user can create the appropriate path to a specially-crafted openssl.cnf file to achieve arbitrary code execution with SYSTEM privileges.

CVE-2020-10140

Acronis True Image 2021 fails to properly set ACLs of the C:\ProgramData\Acronis directory. Because some privileged processes are executed from the C:\ProgramData\Acronis directory, an unprivileged user can achieve arbitrary code execution with SYSTEM privileges by placing a DLL in one of several paths within C:\ProgramData\Acronis.

Impact

By placing a specially-crafted openssl.cnf or DLL file in a specific location, an unprivileged user may be able to execute arbitrary code with SYSTEM privileges on a Windows system with the vulnerable Acronis software installed. See DLL Search Order Hijacking for more details.

Solution

Apply an update

These vulnerabilities are addressed in Acronis True Image 2021 build 32010 (release notes), Acronis Cyber Backup 12.5 build 16363 (release notes), and Acronis Cyber Protect 15 build 24600 (release notes).

Acknowledgements

This vulnerability was reported by Will Dormann of the CERT/CC. Acronis also credits HackerOne researchers @adr, @mmg, @vanitas, @xnand with independently discovering and reporting the vulnerabilities.

This document was written by Will Dormann.

Vendor Information

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Acronis Inc. Affected

Notified: 2020-09-14 Updated: 2020-10-12 CVE-2020-10138	Affected
CVE-2020-10139	Affected CVE-2020-10140

Vendor Statement

We have not received a statement from the vendor.

References

• <https://www.acronis.com/en-us/support/updates/changes.html?p=42226&gt;
• <https://dl.managed-protection.com/u/backup/rn/12.5/user/en-US/AcronisBackup12.5_relnotes.htm&gt;
• <https://dl.managed-protection.com/u/cyberprotect/rn/15/user/en-US/AcronisCyberProtect15_relnotes.htm&gt;
• <https://attack.mitre.org/techniques/T1574/001/&gt;

Other Information

CVE IDs:	CVE-2020-10138 CVE-2020-10139 CVE-2020-10140
Date Public:	2020-10-12 Date First Published: