The Akira ransomware intrusion was reconstructed using only firewall syslog and Windows EVTX logs without EDR or memory captures. Initial access was gained through a brute-force attack on a local SSLVPN account that was disabled in Active Directory but remained active on the firewall without MFA. The attacker performed discovery using Windows process creation events (EID 4688), including domain trust enumeration and group membership queries. Credential access was achieved via Kerberoasting (EID 4769 events with RC4 tickets). Lateral movement occurred mainly through RDP logons (EID 4624 Logon Type 10) from a jump host to critical servers, including domain controllers. Defense evasion involved clearing security logs (EID 1102), stopping endpoint protection services, and deleting shadow copies using vssadmin commands. Encryption followed rapidly after these actions. The analysis underscores that all attack stages were visible in existing logs, but separating perimeter and endpoint logs obscures the full kill chain. Joining these logs by source IP and normalized time reveals the complete attack timeline.

The attacker achieved domain-level privileges, enabling widespread lateral movement and control over critical infrastructure such as domain controllers and backup servers. The final impact was data encryption and deletion of shadow copies, effectively causing a ransomware incident. The attack compromised confidentiality, integrity, and availability of organizational data. No novel or advanced techniques were used, but the lack of MFA on a local VPN account and insufficient log retention allowed the attack to progress undetected until encryption. The incident demonstrates the risk posed by stale credentials and inadequate log management.

A fix or patch is not applicable as this is an attack methodology rather than a software vulnerability. Recommended mitigations include: inventorying all local SSLVPN accounts and enforcing MFA; reconciling firewall user accounts against Active Directory to ensure deprovisioned accounts are disabled everywhere; setting authentication failure thresholds and alerting on excessive failed SSLVPN login attempts; enabling detailed Windows process creation auditing (EID 4688) with increased Security log sizes to retain discovery activity; alerting on Kerberoasting indicators such as multiple RC4 ticket requests (EID 4769); monitoring and alerting on security log clearing events (EID 1102) and shadow copy deletion commands; and ensuring all hosts and firewalls synchronize time to a common authoritative NTP source to enable accurate log correlation. These mitigations are based on observed attack patterns and do not require new patches.