Full Report
Cisco Talos observed a destructive attack on a critical infrastructure entity within Ukraine, using a previously unknown wiper we are calling “PathWiper.”
Analysis Summary
# Incident Report: PathWiper Destructive Attack on Ukrainian Critical Infrastructure
## Executive Summary
A destructive attack was launched against critical infrastructure in Ukraine utilizing a novel wiper malware dubbed "PathWiper." The attack was initiated when threat actors, attributed to a Russia-nexus APT, leveraged an existing legitimate endpoint administration framework to issue malicious commands. The outcome was the corruption of file systems and storage media across affected endpoints through targeted overwriting of critical disk structures, including the MBR.
## Incident Details
- Discovery Date: Not explicitly stated, but implied shortly after execution based on Talos observation.
- Incident Date: Not explicitly stated, likely ongoing or recent at the time of the report.
- Affected Organization: Critical infrastructure entity in Ukraine.
- Sector: Critical Infrastructure.
- Geography: Ukraine.
## Timeline of Events
### Initial Access
- Date/Time: Preceding the issuance of malicious commands.
- Vector: Assumed prior compromise allowing access to a legitimate endpoint administration framework's administrative console.
- Details: Attackers used the existing administrative console to issue commands, mimicking legitimate administrative actions.
### Lateral Movement
- Details: The vector implies that the existing administrative tool was used to deploy the malware across connected endpoints managed by that system. The execution utilized system utilities (WScript.exe) to run a malicious VBScript (`uacinstall.vbs`), which then deployed the final wiper payload (`sha256sum.exe`).
### Data Exfiltration/Impact
- Impact: Destructive wiping of data. PathWiper overwrote the contents of artifacts related to the file system with random data. This included critical components like the MBR, $MFT, $MFTMirr, and other NTFS structures. Files on disk were also overwritten.
### Detection & Response
- Detection: Observed and analyzed by Cisco Talos.
- Response actions taken: Cisco provided technical analysis (this report) and listed protective measures through its product suite (Endpoint, Email, Firewall, etc.). Actual victim response actions are not detailed.
## Attack Methodology
- Initial Access: Compromise or pre-existing access to a legitimate endpoint administration framework console.
- Persistence: Not explicitly detailed, though deployment via a legitimate utility suggests the final payload execution was the primary near-term goal.
- Privilege Escalation: Not explicitly detailed, but necessary to execute administrative commands and deploy malware across endpoints.
- Defense Evasion: File names and actions (`sha256sum.exe`, executing via WScript) were crafted to mimic actions normally performed by the legitimate administrative utility console, suggesting knowledge of the victim environment.
- Credential Access: Not detailed.
- Discovery: PathWiper performed internal discovery of connected storage media, reading drive names, volume paths, and querying registry keys to find network shares (`HKEY_USERS\Network\|RemovePath`).
- Lateral Movement: Through the command-and-control mechanism of the compromised administrative framework.
- Collection: System storage information enumeration (physical drives, volumes, network shares).
- Exfiltration: None mentioned; the goal was destruction (Wiping).
- Impact: Destruction of file system integrity via data overwriting and MBR corruption.
## Impact Assessment
- Financial: Not disclosed.
- Data Breach: Destructive impact on operational data and system integrity; no specific volume disclosed beyond the scope of affected endpoints.
- Operational: High impact due to the deployment of a destructive wiper targeting critical infrastructure.
- Reputational: Not disclosed.
## Indicators of Compromise
- Network indicators: Not provided (URLs/IPs defanged per instruction).
- File indicators:
- Malicious VBScript: `uacinstall.vbs`
- Wiper Executable: `sha256sum.exe`
- Behavioral indicators: Attempts to dismount volumes using `FSCTL_DISMOUNT_VOLUME IOCTL`, overwriting MBR and NTFS artifacts ($MFT, $LogFile, etc.).
- Snort 2 rules: 64742, 64743
- Snort 3 rules: 301174
- File Hash (SHA256): `7C792A2B005B240D30A6E22EF98B991744856F9AB55C74DF220F32FE0D00B6B3`
## Response Actions
- Containment: Actions are not detailed for the victim, but mitigation relies on leveraging existing security products (Cisco Secure Endpoint, Firewall) to block execution and malicious activity.
- Eradication: Implied need to reimage systems and restore data from backups due to destructive nature.
- Recovery actions: Not detailed.
## Lessons Learned
- The continuing high threat of destructive attacks against Ukrainian entities requires vigilance, even against established defensive postures.
- Reliance on legitimate, powerful endpoint administration tools can create a significant security blind spot if their management consoles are compromised, as these tools can be used to seamlessly deploy destructive payloads while blending in with normal administrative noise.
## Recommendations
- Implement robust Multi-Factor Authentication (MFA) for all administrative consoles, especially those that control endpoint deployment (e.g., Cisco Duo recommendation).
- Ensure endpoint detection and response capabilities are configured to detect process chains involving legitimate tools spawning scripts for unexpected file execution (e.g., WScript executing temporary VBScript).
- Continuously monitor and audit logs generated by endpoint administration frameworks to detect anomalous command execution patterns.
- Maintain up-to-date backups and tested recovery plans specifically for MBR and full-volume corruption scenarios.