Security Advisory 2021-02
| Summary | Local privilege escalation in Octopus Tentacle (CVE-2021-26557) |
| Advisory Number | 2021-02 |
| Discovery Date | 01 Jan 2021 |
| Patch Release Date | 07 Mar 2021 |
| Advisory Release Date | 10 Mar 2021 |
| Product | Octopus Tentacle |
| Operating System | Windows |
| Severity | High |
| CVE ID | CVE-2021-26557 |
Customers who have downloaded and installed any of the Octopus Tentacle versions listed below ("Details") are affected.
Please upgrade your Octopus Tentacle immediately to fix this vulnerability.
Customers using Octopus Cloud are not affected.
Customers who have upgraded Octopus Tentacle to version 6.0.489 or higher are not affected.
Severity
Octopus Deploy has given this vulnerability a high rating. This rating was given according to the Octopus Deploy severity levels, which ranks vulnerabilities as critical, high, medium, or low severity.
This is our assessment and you should evaluate its applicability to your own environment.
Details
When Octopus Tentacle is installed using a custom folder location, folder ACLs are not set correctly and could lead to an unprivileged user using DLL side-loading to gain privileged access.
All versions of Octopus Tentacle are affected by this vulnerability.
Fix
To address this vulnerability, we have released Octopus Tentacle version:
- 6.0.489
The latest versions of Octopus Deploy products can be downloaded from https://octopus.com/downloads and previous versions can be downloaded from https://octopus.com/downloads/previous
What You Need to Do
Octopus Deploy recommends that you upgrade to the latest version (6.0.489). You can download the latest version of Octopus Tentacle from https://octopus.com/downloads
If you can't upgrade to the latest version (6.0.489):
| If you have feature version... | ...then upgrade to this version |
|---|---|
| 3.x or greater | 6.0.489 |
For Octopus Tentacle versions before 3.x please contact our support team https://octopus.com/support for advice on upgrading to the latest version.
Mitigation
If you are unable to patch your Octopus Tentacle installation you can effectively mitigate this vulnerability by removing any “CreateFiles” or “AppendData” permissions for “BUILTIN\Users” on the Octopus Tentacle installation directory.
The following links are for the PowerShell commands that can be used to check folder ACLs and update them:
- https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/get-acl?view=powershell-7.1
- https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-acl?view=powershell-7.1
Support
If you have any questions or concerns regarding this advisory, please contact our support team https://octopus.com/support.
Exploitation and Public Announcements
The Octopus Deploy security team is not aware of any malicious use of the vulnerability that is described in this advisory.
Source
This vulnerability was found by Octopus Deploy Engineering.