VPN Brute Force: Credential Attack on the Remote-Access Portal
A password-spray campaign targets the Halcyon Freight SSL-VPN portal from two rotating source IPs, submitting credentials across many accounts to stay under per-account lockout thresholds. One account eventually matches. Reconstruct the spray, identify the compromised account and the operator IP that opened the active session, and trace the first move the attacker made over the tunnel.
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Investigation Tasks
Complete each task by investigating alerts and submitting your findings.
Identify the attack pattern in the VPN logs
15Something unusual is happening at the remote-access portal this morning. Before the team escalates, establish what kind of activity you are looking at.
Determine how many accounts were targeted
10The spray hit more than one account. Establish the exact count of distinct account names that appear in the failure events from the 185.159.0.0/24 block.
Find the account where the spray succeeded
15One account in the target list had a password that matched. Identify it.
Identify the IP that opened the active session
15After the spray found a working credential, the attacker shifted to a different IP to establish the actual VPN session. Find that source address.
Trace the movement over the tunnel
20Within minutes of gaining VPN access, the attacker began probing inside the network. Determine which internal host they attempted to reach and over which protocol.
Classify the access technique
15The attacker used legitimate stolen credentials to gain access through the VPN portal. Map this to the MITRE ATT&CK technique for using valid accounts to authenticate to external services.
6 tasks · 90 points total
Training Tools
Skills You'll Build
Ideal for newcomers to SOC operations. Guided investigation with clear indicators.
Prerequisites
- No prior experience required
- Familiarity with SIEM concepts
- Familiarity with Firewall concepts
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