[Hardening] F-15: Failure to Block Abusers by IPs.

### The required feature described as a wish

**Description:** CloudStack does not monitor or restrict API authentication attempts based on the source IP address. A single client can submit unlimited failed authentication attempts across any number of accounts without being identified or blocked.

**Affected Components:** Management API

**Impact:** An attacker operating from a single source address can systematically target multiple user accounts with repeated failed login attempts, deliberately triggering lockouts across all accounts, preventing legitimate users and administrators from accessing the platform.

**Steps to Reproduce:**
- Using a custom script or a brute-forcing tool (e.g., `hydra`), send a high volume of failed authentication attempts targeting multiple user accounts.
- Observe that the requests are processed without any source IP tracking, flagging, or blocking.
- Confirm that targeted accounts transition to a disabled state while the source IP remains unrestricted.

**Recommended Remediation:** Log all authentication attempts and source IPs to `/var/log/cloudstack/management/auth.log` so tools like Fail2Ban can automatically detect brute-force attacks and block malicious traffic (via `iptables` or `nftables`). For even faster protection, a system administrator can craft a custom script using `inotify` to trigger real-time blocks via network edge appliances, stopping attackers' traffic before they ever reach CloudStack.

Start with the CloudStack Management API authentication flow and determine where failed attempts and source IPs can be observed. Use the proposed /var/log/cloudstack/management/auth.log output as the expected integration point, then reproduce attacks with a custom script or hydra and verify that attempts are logged in a form Fail2Ban can use for blocking.

Written by the indexing model from the issue text.