Full Report
This diary walks through a recent Akira-attributed intrusion at a mid-sized organization. The reconstruction used only SSLVPN syslog and Windows EVTX exports. No EDR. No memory captures. Every identifier in the post has been anonymized. The event types and sequencing are preserved exactly as observed.
Analysis Summary
# Incident Report: Akira Ransomware Intrusion at Mid-Sized Organization
## Executive Summary
A mid-sized organization fell victim to an Akira ransomware attack initiated through a brute-forced local SSLVPN account lacking Multi-Factor Authentication (MFA). The threat actors moved laterally via RDP using compromised administrative credentials and Kerberoasting techniques, eventually gaining Domain Admin privileges. The incident resulted in full-scale encryption of the environment, including file servers, domain controllers, and backup systems.
## Incident Details
- **Discovery Date:** May 2026 (approximate based on publication)
- **Incident Date:** Event spanned approximately 7 days prior to encryption
- **Affected Organization:** Anonymized (Mid-sized organization)
- **Sector:** Not specified
- **Geography:** Single-site location
## Timeline of Events
### Initial Access
- **Date/Time:** T-Minus 72 hours from encryption
- **Vector:** SSLVPN Brute Force / Credential Stuffing
- **Details:** A single source IP targeted a local firewall account that was deprovisioned in Active Directory but still active on the firewall. The account lacked MFA.
### Lateral Movement
- **Details:** The attacker used a legitimate jump host already present in the environment. From there, they used RDP (Logon Type 10) to access critical infrastructure including the File Server, Domain Controllers, and Backup Server.
### Data Exfiltration/Impact
- **Details:** The attack culminated in the deployment of Akira ransomware. Files were encrypted across the network. (Note: While Akira typically exfiltrates data, this specific log analysis focused on the kill chain leading to encryption).
### Detection & Response
- **How it was discovered:** Discovery was reactive, following the appearance of ransom notes and encrypted files.
- **Response actions taken:** Post-incident reconstruction using SSLVPN syslog and Windows Event Logs (EVTX); attribution confirmed via ransom note analysis.
## Attack Methodology
- **Initial Access:** Brute-force/Credential stuffing against SSLVPN local account.
- **Persistence:** Creation of a new user account in a non-default Organizational Unit (OU).
- **Privilege Escalation:** Kerberoasting (EID 4769) against three service accounts using RC4 encryption.
- **Defense Evasion:** Use of legitimate administrative tools (Living-off-the-Land) and RDP to blend in with normal admin traffic.
- **Credential Access:** Kerberoasting and likely harvesting of credentials stored on the jump host.
- **Discovery:** Execution of `nltest /dclist`, `net group "Domain Admins" /domain`, `whoami /all`, and `AdFind.exe`.
- **Lateral Movement:** RDP (Remote Desktop Protocol) via EID 4624 Type 10.
- **Impact:** Deployment of Akira ransomware targeting servers and backups.
## Impact Assessment
- **Financial:** Significant costs associated with recovery and potential downtime (specifics not disclosed).
- **Data Breach:** High probability of data theft (standard Akira TTP).
- **Operational:** Severe disruption; critical servers and backup infrastructure were encrypted.
- **Reputational:** Impact to clients and stakeholders due to service interruption.
## Indicators of Compromise
- **Network indicators:**
- Unauthorized SSLVPN logins from hosting provider IP ranges.
- Kerberoasting activity (EID 4769) targeting service accounts.
- **File indicators:**
- Ransomware binary (Akira).
- `AdFind.exe` (Discovery tool).
- `.txt` ransom notes.
- **Behavioral indicators:**
- High volume of failed login attempts followed by a single success.
- Administrative commands (`nltest`, `net group`) originating from unusual contexts.
- New administrative account created in a non-standard OU.
## Response Actions
- **Containment:** (Inferred) Disabling the compromised SSLVPN account and cleaning the jump host.
- **Eradication:** Identification and removal of the unauthorized AD account and ransomware binaries.
- **Recovery:** Reconstruction of the timeline via log analysis to determine the extent of the compromise.
## Lessons Learned
- **Orphaned Accounts:** Accounts disabled in Active Directory must also be removed from local firewall databases.
- **MFA Gaps:** Any entry point (especially SSLVPN) lacking MFA is a high-risk liability.
- **Logging Gaps:** The lack of EDR and centralized log management made real-time detection impossible, forcing a reactive post-mortem.
## Recommendations
- **Enforce MFA:** Implement Multi-Factor Authentication on all remote access points without exception.
- **Identity Lifecycle Management:** Establish a process to ensure deprovisioning occurs across all platforms (AD, Firewalls, SaaS).
- **Monitor for Kerberoasting:** Alert on EID 4769 where Ticket Options indicate RC4 encryption (`0x40810000`) for service accounts.
- **Restricted Admin RDP:** Implement "Restricted Admin" mode or RDP Guard to prevent credential theft on jump hosts.
- **Geoblocking:** Restrict VPN access to known geographic locations of employees to reduce the attack surface.