KRB_AP_ERR_SKEW | Clock difference > 5 minutes between attacker and DC | Sync time: sudo ntpdate -u <DC_IP> or sudo timedatectl set-ntp off && sudo date -s "$(curl -s http://<DC_IP>)" |
KDC_ERR_PREAUTH_FAILED | Wrong password or hash | Verify credentials |
KDC_ERR_C_PRINCIPAL_UNKNOWN | User does not exist | Check username and domain |
KDC_ERR_CLIENT_REVOKED | Account disabled or locked | Account is unusable |
KDC_ERR_ETYPE_NOSUPP | DC doesn’t support the encryption type | Try a different key type (password vs AES vs NTLM) |
KRB_ERR_RESPONSE_TOO_BIG | KDC response exceeded the UDP size limit (user in many groups) | Impacket automatically retries over TCP — no action needed |