How Unified EDR and ITDR Stop Attacks Before They Spread
Huntress details the operational benefits of unifying EDR and ITDR to combat infostealers and rapid credential abuse. A highlighted incident demonstrates a ClickFix social engineering attack leveraging WebDAV and rundll32.exe to execute a remote payload, which was mitigated by automatically isolating the host and revoking associated Microsoft 365 identity sessions.
- domainframe[.]mess-laboratory[.]in[.]netDomain hosting malicious library for ClickFix social engineering attack
- domainpack3-frame[.]mess-laboratory[.]in[.]netDomain used in remote UNC path for WebDAV payload execution
- domainxvy42z[.]mess-laboratory[.]in[.]netDomain used for WebDAV connectivity via davclnt.dll
- filename\\pack3-frame.mess-laboratory.in.net\05fe317c-0981-4de2-bc8a-930d369db441\3d80df5d12cdfe6450a782fc87bf66b444.googleRemote UNC path used to load malicious DLL via Windows Run dialog
Detection / Hunter
What Happened
A recent cyberattack used a deceptive technique called 'ClickFix' to trick a user into running malicious software on their Windows computer. This type of attack, known as an infostealer, aims to silently steal passwords and login sessions to access company accounts. Because attackers use stolen logins very quickly, traditional security tools often react too late. By combining computer monitoring with identity protection, security teams can instantly lock down compromised accounts and stop the attack before it spreads. Organizations should ensure their security tools can automatically revoke user access when a device is infected.
Key Takeaways
- Infostealers are highly effective at harvesting credentials and session tokens, leading to rapid identity abuse before traditional logs can be analyzed.
- A real-world ClickFix social engineering attack utilized the Windows Run dialog and rundll32.exe to execute a remote payload via WebDAV.
- Traditional incident response suffers from a critical time gap between endpoint detection and identity remediation due to log latency.
- Unifying EDR and ITDR allows for automated, immediate revocation of cloud identity sessions when an endpoint compromise is detected.
Affected Systems
- Windows
- Microsoft 365
- Entra ID
Attack Chain
The attack begins with a ClickFix social engineering lure, tricking the user into executing a command via the Windows Run dialog. This command uses rundll32.exe to load a malicious DLL from a remote UNC path over WebDAV. The WebClient service resolves the path, and rundll32.exe invokes davclnt.dll (specifically the DavSetCookie function) to establish connectivity to the remote server. Once executed, the infostealer harvests credentials and session tokens for immediate reuse.
Detection Availability
- YARA Rules: No
- Sigma Rules: No
- Snort/Suricata Rules: No
- KQL Queries: No
- Splunk SPL Queries: No
- EQL Queries: No
- Other Detection Logic: No
No specific detection rules are provided in the article, though behavioral indicators for WebDAV and rundll32.exe usage are described in the incident report image.
Detection Engineering Assessment
EDR Visibility: High — EDR solutions can easily monitor rundll32.exe executing files from remote UNC paths and loading specific DLLs like davclnt.dll. Network Visibility: Medium — WebDAV traffic to external domains can be monitored, though it may blend with legitimate HTTP/HTTPS traffic depending on the environment. Detection Difficulty: Moderate — While the specific WebDAV execution is highly anomalous, correlating it with immediate identity abuse requires integrated ITDR/EDR capabilities or fast SIEM pipelines to beat the attacker's speed.
Required Log Sources
- Process Creation (Event ID 4688 / Sysmon Event ID 1)
- Image Load (Sysmon Event ID 7)
- Cloud Identity Logs (Entra ID / M365)
Hunting Hypotheses
| Hypothesis | Telemetry | ATT&CK Stage | FP Risk |
|---|---|---|---|
| Look for rundll32.exe executing files from external UNC paths, particularly those associated with WebDAV. | Process execution logs with command-line arguments | Execution | Low |
| Identify rundll32.exe loading davclnt.dll and calling the DavSetCookie function. | Image load logs and API monitoring | Execution | Low |
Control Gaps
- Latency in audit log ingestion delaying identity remediation
- Siloed EDR and Identity protection tools
Key Behavioral Indicators
- rundll32.exe executing from a UNC path
- davclnt.dll loaded by rundll32.exe
False Positive Assessment
- Low
Recommendations
Immediate Mitigation
- Isolate endpoints exhibiting suspicious rundll32.exe or WebDAV activity.
- Revoke active sessions and disable identities for users associated with compromised endpoints.
Infrastructure Hardening
- Block outbound WebDAV traffic to external untrusted domains.
- Implement conditional access policies to require re-authentication upon risk detection.
User Protection
- Deploy unified EDR and ITDR solutions to automate identity remediation upon endpoint compromise.
- Restrict access to the Windows Run dialog for non-administrative users if feasible.
Security Awareness
- Train users to recognize ClickFix social engineering lures and avoid executing commands from untrusted sources.
MITRE ATT&CK Mapping
- T1204.002 - User Execution: Malicious File
- T1059 - Command and Scripting Interpreter
- T1218.011 - System Binary Proxy Execution: Rundll32
- T1071.001 - Application Layer Protocol: Web Protocols
- T1552 - Credentials in Files
- T1539 - Steal Web Session Cookie
Additional IOCs
- Command Lines:
- Purpose: Execute remote DLL via WebDAV | Tools:
rundll32.exe,Windows Run dialog| Stage: Execution |rundll32.exe \\pack3-frame.mess-laboratory.in.net\
- Purpose: Execute remote DLL via WebDAV | Tools:
- Other:
davclnt.dll- Invoked by rundll32.exe with DavSetCookie function to establish WebDAV connectivity
