Detect Clear Network Connection History and Configurations in CrowdStrike LogScale
Adversaries may clear or remove evidence of malicious network connections in order to clean up traces of their operations. Configuration settings as well as various artifacts that highlight connection history may be created on a system and/or in application logs from behaviors that require network connections, such as Remote Services or External Remote Services. Network connection history may be stored in Windows Registry values under HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\Default and Servers, in files such as Default.rdp and RDP cache files, or in system logs on macOS and Linux. Adversaries may delete or modify this data to conceal indicators and impede defensive analysis.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1070 Indicator Removal
- Sub-technique
- T1070.007 Clear Network Connection History and Configurations
- Canonical reference
- https://attack.mitre.org/techniques/T1070/007/
LogScale Detection Query
#event_simpleName in ("RegValueDelete", "RegKeyDelete", "ProcessRollup2", "SyntheticProcessRollup2")
| case {
// RDP Registry History Deletion via registry key or value deletion events
#event_simpleName in ("RegValueDelete", "RegKeyDelete")
| RegObjectName = /(?i)Terminal Server Client\\(Default|Servers)/
| DetectionCategory := "RDP Registry History Deletion"
| ArtifactAffected := RegObjectName;
// CLI Network History Cleanup via process execution
#event_simpleName in ("ProcessRollup2", "SyntheticProcessRollup2")
| CommandLine = /(?i)(netsh\s+(wlan\s+delete|advfirewall\s+reset|int\s+ip\s+reset|interface\s+ip\s+reset)|Clear-DnsClientCache|ipconfig\s+\/flushdns|dnscmd\s+\/clearcache|arp\s+-d|route\s+delete|(del|Remove-Item|erase|reg\s+delete).*(Terminal Server Client|Default\.rdp))/
| DetectionCategory := "CLI Network History Cleanup"
| ArtifactAffected := CommandLine;
*
| DetectionCategory := "NOMATCH"
}
| DetectionCategory != "NOMATCH"
| table(
[_time, ComputerName, UserName, ImageFileName, CommandLine, RegObjectName, ArtifactAffected, DetectionCategory],
sortby="_time",
order="desc"
)CrowdStrike Falcon LogScale (CQL) detection for T1070.007. Monitors RegValueDelete and RegKeyDelete sensor events for deletions targeting RDP connection history registry keys (HKCU\Software\Microsoft\Terminal Server Client\Default and Servers), and ProcessRollup2/SyntheticProcessRollup2 events where the command line contains network state erasure patterns including netsh resets, arp -d, route delete, DNS cache flush commands, and explicit deletion commands targeting Terminal Server Client paths or Default.rdp files.
Data Sources
Required Tables
False Positives & Tuning
- CrowdStrike Falcon Real Time Response (RTR) sessions where analysts execute netsh or registry commands to remediate or troubleshoot endpoints — correlate DetectionCategory against RTR session IDs
- Legitimate use of PowerShell Clear-DnsClientCache in scheduled task scripts for performance tuning or network testing pipelines on developer or lab machines
- Enterprise VPN clients and network management agents (e.g., Cisco AnyConnect, SolarWinds, PRTG agents) issuing route delete and arp -d commands during normal connection lifecycle management
Other platforms for T1070.007
Testing Methodology
Validate this detection against 5 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Delete RDP Connection History from Registry
Expected signal: Sysmon Event ID 12 (RegistryEvent - Object Delete): TargetObject will contain 'Software\Microsoft\Terminal Server Client\Default' and 'Software\Microsoft\Terminal Server Client\Servers'. Sysmon Event ID 1 (Process Create): reg.exe with CommandLine containing 'reg delete' and 'Terminal Server Client'. Security Event ID 4688 (if command line auditing enabled) showing the reg.exe execution.
- Test 2Delete Default RDP Connection File
Expected signal: Sysmon Event ID 11 (File Create): TargetFilename will show the creation of Default.rdp. Sysmon Event ID 23 (File Delete, if enabled): TargetFilename will show the deletion of Default.rdp. Sysmon Event ID 1 (Process Create): cmd.exe with CommandLine containing 'del' and 'Default.rdp'.
- Test 3Clear DNS Client Cache to Remove Connection Evidence
Expected signal: Sysmon Event ID 1 (Process Create): ipconfig.exe with CommandLine 'ipconfig /flushdns'. Security Event ID 4688 (if command line auditing enabled) with same data. Note: this is a common operation so additional context (time of day, parent process, user account) is needed to distinguish malicious use.
- Test 4Reset Windows Firewall Configuration via Netsh
Expected signal: Sysmon Event ID 1 (Process Create): netsh.exe with CommandLine 'netsh advfirewall reset'. Security Event ID 4688 (if command line auditing enabled). Additionally, Security Event ID 4950 (Windows Firewall setting has changed) may be generated in the Windows Firewall with Advanced Security operational log.
- Test 5PowerShell Removal of RDP Cache Directory Contents
Expected signal: Sysmon Event ID 1 (Process Create): powershell.exe with CommandLine containing 'Remove-Item' and 'Terminal Server Client'. Sysmon Event ID 23 (File Delete): TargetFilename showing deletion within the Terminal Server Client\Cache path. PowerShell ScriptBlock Log Event ID 4104 with the full script content.
References (10)
- https://attack.mitre.org/techniques/T1070/007/
- https://docs.microsoft.com/troubleshoot/windows-server/remote/remove-entries-from-remote-desktop-connection-computer
- https://www.osdfcon.org/presentations/2020/Brian-Moran_Putting-Together-the-RDPieces.pdf
- https://www.mandiant.com/resources/blog/fortinet-malware-ecosystem
- https://www.secureworks.com/blog/bronze-silhouette-targets-us-government-and-defense-organizations
- https://www.microsoft.com/security/blog/2021/01/20/deep-dive-into-the-solorigate-second-stage-activation-from-sunburst-to-teardrop-and-raindrop/
- https://github.com/ANSSI-FR/bmc-tools
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/netsh
- https://www.freedesktop.org/software/systemd/man/systemd-journald.service.html
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1070.007/T1070.007.md
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