Overview
SMA Technologies OpCon UNIX agent adds the same SSH key on every installation and subsequent updates. An attacker with access to the private key can gain root access on affected systems.
Description
During OpCon UNIX agent installation and updates, an SSH public key is added to the root account's authorized_keys file. The corresponding private key titled sma_id_rsa is included with the installation files and is not encrypted with a passphrase. Removal of the OpCon software does not remove the entry from the authorized_keys file.
Impact
An attacker with access to the private key included with the OpCon UNIX agent installation files can gain SSH access as root on affected systems.
Solution
Remove private key
SMA Technologies has provided a tool to address the issue.
Another option is to manually remove the SSH key entry from root's authorized_keys file. The key can be identified by its fingerprints:
SHA256:qbgTVNkLGI5G7erZqDhte63Vpw+9g88jYCxMuh8cLeg
MD5:f1:6c:c9:ba:21:66:ce:7c:5a:55:e2:4d:07:72:cc:31
Depending on the shell and operating system there are various ways to generate fingerprints for public keys listed in authorized_keys.
Upgrade
SMA Technologies reports that "We have updated our UNIX agent version 21.2 package to no longer include (and also remove) any existing vulnerability."
Acknowledgements
Thanks to Nick Holland at Holland Consulting for researching and reporting this vulnerability.
This document was written by Kevin Stephens.
