Summary
Static SSH host key vulnerability in old Vanilla OS image versions allowed any unauthenticated user to perform man-in-the-middle (MITM) attack on a Vanilla OS host who had SSH enabled.
Details
Vanilla OS contained static SSH host keys in the core-image in versions predating v1.1.1. Which led to every Vanilla OS installation having the same SSH host keys. These keys can be easily extracted from the old core-image:
$ docker run -it ghcr.io/vanilla-os/core:v1.1.0 sh
# cat /etc/ssh/ssh_host_rsa_key
-----BEGIN OPENSSH PRIVATE KEY-----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-----END OPENSSH PRIVATE KEY-----
PoC
An attacker could exploit this by performing man-in-the-middle (MITM) attacks. By impersonating the target server using the known keys during SSH handshake, the attacker can intercept into the SSH connection without being detected by users, and then execute arbitrary commands on the target server.
Impact
Users enabling and using the SSH server on Vanilla OS before v1.1.1 of core image (released in January 2025) were at risk.
This issue has been resolved since v1.1.1 of core image in January 2025 and the fix has reached all users with auto updates enabled by February 2025.
Summary
Static SSH host key vulnerability in old Vanilla OS image versions allowed any unauthenticated user to perform man-in-the-middle (MITM) attack on a Vanilla OS host who had SSH enabled.
Details
Vanilla OS contained static SSH host keys in the
core-imagein versions predating v1.1.1. Which led to every Vanilla OS installation having the same SSH host keys. These keys can be easily extracted from the oldcore-image:PoC
An attacker could exploit this by performing man-in-the-middle (MITM) attacks. By impersonating the target server using the known keys during SSH handshake, the attacker can intercept into the SSH connection without being detected by users, and then execute arbitrary commands on the target server.
Impact
Users enabling and using the SSH server on Vanilla OS before v1.1.1 of core image (released in January 2025) were at risk.
This issue has been resolved since v1.1.1 of core image in January 2025 and the fix has reached all users with auto updates enabled by February 2025.