NCAE Mapping Hub
Overview Scoreboard Data Roles Exercised Checklists Lessons Skill Drills Practice Terminal Progress
SSH Login partial 2x weight measured

SSH partial. scoring-engine users' public keys missing or wrong permissions

The following users failed to authenticate with their public key: simone_weil, claude_chevalley, vetomo
Events
6
Pts per check
2.8
Pts missed
16.7
Teams hit
1/13

Authority mappings

Which work roles, knowledge units, and EWU courses this error pattern touches. Hover for context, click to drill in.

DCWF roles: CE-463 Host Analyst CS-462 Control Systems Security Specialist CS-521 Cyber Defense Infrastructure Support Specialist CS-531 Cyber Defense Incident Responder EN-211 Forensics Analyst IT-411 Technical Support Specialist IT-451 System Administrator
Knowledge Units: CD-BCY Basic Cryptography CD-NDF Network Defense CD-OSA Operating Systems Administration CD-OSC Operating Systems Concepts CD-OSH Operating Systems Hardening
EWU courses: CSCD240-S26 CSCD212 CSCD240 CSCD379 CSCD380 CSCD381 CSCD434 CSCD470 MATH380

What the message means

The scoring engine connected to sshd but could not authenticate some of its seeded users (e.g. `simone_weil`, `nills`, `todd_k`). Either their public keys are missing from `~/.ssh/authorized_keys`, or the key/perms got altered during hardening. This is a 'partial' status. some users still work, so the service isn't fully down.

Why the service is down

Commands in order

  1. 1. 1. Does sshd allow pubkey auth?
    grep -E 'PubkeyAuthentication|PasswordAuthentication' /etc/ssh/sshd_config
    Expect
    PubkeyAuthentication yes
    Interpret and next
    If no/missing: set `PubkeyAuthentication yes`, restart sshd.
  2. 2. 2. Does the user exist?
    id simone_weil
    Expect
    uid=NNNN(simone_weil) gid=.
    Interpret and next
    `id: no such user` = user was deleted. Recreate from packet info.
  3. 3. 3. Do they have an authorized_keys file?
    ls -la /home/simone_weil/.ssh/authorized_keys
    Expect
    -rw------- 1 simone_weil simone_weil . authorized_keys
    Interpret and next
    Missing = key was wiped; restore from `/root/ssh-keys-backup/`. Wrong perms = see step 4.
  4. 4. 4. Fix the permission triad (common silent failure)
    chown -R simone_weil:simone_weil /home/simone_weil/.ssh chmod 700 /home/simone_weil/.ssh chmod 600 /home/simone_weil/.ssh/authorized_keys
    Expect
    No errors
    Interpret and next
    sshd refuses to use pubkey if these are loose. This is often the actual bug.
  5. 5. 5. Confirm from sshd's perspective
    sshd -T | grep -iE 'pubkeyauthentication|authorizedkeys'
    Expect
    pubkeyauthentication yes; authorizedkeysfile .ssh/authorized_keys
    Interpret and next
    If authorizedkeysfile is non-default, check that path.
  6. 6. 6. Try a manual SSH attempt and read the auth log
    tail -20 /var/log/auth.log
    Expect
    Line naming the accepted publickey for simone_weil
    Interpret and next
    `Authentication refused: bad ownership or modes` = redo step 4 for that user.

Decision tree

Answer each question to route to the right fix.

Q: Does the user exist in /etc/passwd?
Yes:
Q: Does authorized_keys exist with perms 600?
Yes:
Q: Is ~/.ssh 700 and owned by the user?
Yes: Check sshd_config for PubkeyAuthentication + AllowUsers.
No: Fix ownership and mode.
No: Restore from backup; chmod 600; chown user:user.
No: Recreate the user from packet info.

External references

Other patterns on this service