Full Report
Key Takeaways In late December 2022, we observed threat actors exploiting a publicly exposed Remote Desktop Protocol (RDP) host, leading to data exfiltration and the deployment of Trigona ransomware. On … Read More
Analysis Summary
# Incident Report: Rapid Trigona Ransomware Deployment via Exposed RDP
## Executive Summary
In late December 2022, threat actors gained initial access to the network via a publicly exposed Remote Desktop Protocol (RDP) host using legitimate credentials. Within approximately three hours, the attackers executed extensive discovery, data exfiltration using Rclone to Mega.io, disabled security controls, and deployed Trigona ransomware across accessible hosts via SMB. The incident resulted in dual extortion due to data theft and system encryption.
## Incident Details
- Discovery Date: Late December 2022 (Specific date not provided, noted as occurring "in late December 2022")
- Incident Date: Late December 2022 (Ransomware executed on Christmas Eve)
- Affected Organization: Undisclosed
- Sector: Undisclosed
- Geography: Undisclosed
## Timeline of Events
### Initial Access
- Date/Time: Late December 2022 (Likely started days or weeks prior based on prior logins)
- Vector: Exploitation of publicly exposed Remote Desktop Protocol (RDP) host.
- Details: Initial login used legitimate credentials for the default Administrator account; no brute-forcing evidence suggested existing credentials, potentially from an access broker.
### Lateral Movement
- Date/Time: Approximately 20 minutes after initial access.
- Details: Threat actors used RDP to connect from the beachhead host to one file server, copied their toolkit, and later connected to a second file server and a backup server.
### Data Exfiltration/Impact
- Date/Time: Initiated shortly after establishing presence on file servers (approx. 45 minutes post-initial access). Ransomware execution was approximately 2 hours and 49 minutes post-initial access.
- Details: Data exfiltration was performed using a batch script to execute Rclone to Mega.io. Subsequently, the Trigona ransomware binary was staged and executed across all accessible hosts, propagating via SMB.
### Detection & Response
- Date/Time: Post-incident analysis following the impact.
- Details: The report indicates the analysis was performed retrospectively (Internal case #19172). Specific detection and response actions implemented during the live incident are not detailed, but the analysis revealed disabling of Windows Defender and the use of legitimate tools like Netscan for discovery.
## Attack Methodology
- Initial Access: Valid Accounts (T1078) via External Remote Services (T1133) on RDP (T1021.001).
- Persistence: Establishment of a new user account via batch scripts (Implied for redundancy, though not explicitly detailed as the primary persistence mechanism).
- Privilege Escalation: Not explicitly detailed, but the use of the default Administrator account suggests immediate high privileges.
- Defense Evasion: Disabling Windows Defender via commands executed on all compromised hosts (T1562.001).
- Credential Access: Not explicitly detailed, but initial access used existing credentials.
- Discovery: SoftPerfect’s Netscan tool used for automated network scanning and discovery (Remote System Discovery T1018, Network Share Discovery T1135, File and Directory Discovery T1083).
- Lateral Movement: Remote Desktop Protocol (T1021.001) to move between servers.
- Collection: Accessing and exploring network shares and documents via a web browser.
- Exfiltration: Data exfiltration executed via a batch script leveraging Rclone to cloud storage (Mega.io) (Exfiltration to Cloud Storage T1567.002).
- Impact: Deployment and execution of Trigona ransomware (Data Encrypted for Impact T1486).
## Impact Assessment
- Financial: Not specified, but significant due to ransomware payment negotiation/recovery costs.
- Data Breach: Sensitive data was exfiltrated prior to encryption (Dual extortion).
- Operational: Widespread encryption of network-accessible hosts using SMB propagation, leading to business disruption.
- Reputational: Potential damage due to the public nature of data theft and ransomware event.
## Indicators of Compromise
- Network indicators: RDP connections from multiple IPs; traffic to Mega.io domain (defanged: [mega.io]).
- File indicators: Batch scripts used for execution and configuration; Rclone binary; Trigona ransomware binary.
- Behavioral indicators: Use of SoftPerfect Netscan for mass discovery; execution of commands to disable Windows Defender; use of SMB to propagate ransomware.
## Response Actions
*Containment/Eradication/Recovery actions are not specified in the provided text, as the context summarizes the intrusion analysis rather than the live response.*
## Lessons Learned
- RDP exposure remains a critical vulnerability, especially when paired with potentially compromised or weak credentials.
- Attackers can achieve total network compromise leading to ransomware deployment extremely rapidly (under 3 hours).
- Threat actors are utilizing commodity tools (`Netscan`, `Rclone`) and custom scripts to automate discovery, defense evasion, and exfiltration when initial access is secured.
- The use of legitimate credentials allowed the attacker to operate effectively without immediate alerting on common indicators like brute-force attempts.
## Recommendations
- Immediately restrict or eliminate external RDP access, favoring VPNs or secure access gateways.
- Implement Multi-Factor Authentication (MFA) on all remote access services, including RDP.
- Conduct rigorous network share access reviews and implement least privilege across the environment.
- Enhance endpoint detection and response (EDR) capabilities to monitor for common post-exploitation activities such as the disabling of security tools (Windows Defender) and the use of network scanning tools like Netscan.
- Continuously monitor for lateral movement indicators (e.g., RDP usage between disparate internal hosts by unusual accounts).