Detect Network Share Connection Removal in CrowdStrike LogScale
Adversaries remove Windows network share connections after use to clean up traces of lateral movement and data access. Network shares mapped via net use or UNC paths leave artifacts in the Windows registry (HKCU\Network), Windows event logs (Event ID 5140 — network share object accessed, Event ID 5142 — network share created), and in the MRU list. The primary utility for removal is net use \\target\share /delete or net use * /DELETE /Y to remove all mapped drives simultaneously. RobbinHood ransomware used net use * /DELETE /Y to disconnect all network shares before encryption, likely to ensure local encryption of any mapped network paths. Threat Group-3390 detached network shares after exfiltrating files. InvisiMole, DUSTTRAP (APT41), and various ransomware families routinely perform share cleanup as a post-exploitation step.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1070 Indicator Removal
- Sub-technique
- T1070.005 Network Share Connection Removal
- Canonical reference
- https://attack.mitre.org/techniques/T1070/005/
LogScale Detection Query
// Primary detection: net.exe / net1.exe share deletion
#event_simpleName=ProcessRollup2
| FileName in ("net.exe", "net1.exe", ignoreCase=true)
| CommandLine = /use/i
| CommandLine = /(\/delete|\/DELETE|\ \/d\ )/
| eval BulkDelete = if(CommandLine = /use\s+\\\\\*/, "YES", "NO")
| eval Severity = if(BulkDelete = "YES", "CRITICAL", "HIGH")
| eval TechniqueID = "T1070.005"
| eval TechniqueName = "Network Share Connection Removal"
| table([@timestamp, ComputerName, UserName, CommandLine, ParentProcessId, FileName, BulkDelete, Severity, TechniqueID, TechniqueName])
| sort(field=@timestamp, order=desc)
// Supplementary: detect net use wildcard bulk removal (pre-ransomware indicator)
#event_simpleName=ProcessRollup2
| FileName in ("net.exe", "net1.exe", ignoreCase=true)
| CommandLine = /use\s+\\\\\*\s+\/DELETE/i
| groupBy([ComputerName, UserName], function=[
count(as=ExecutionCount),
collect([CommandLine]),
min(@timestamp, as=FirstSeen),
max(@timestamp, as=LastSeen)
])
| where ExecutionCount >= 1
| eval RansomwareIndicator = "HIGH - Bulk Share Removal"
| sort(field=LastSeen, order=desc)Detects network share connection removal in CrowdStrike Falcon via ProcessRollup2 events. Matches net.exe and net1.exe command lines containing share deletion flags. Includes a secondary groupBy query to surface bulk wildcard deletions (net use * /DELETE) as a high-confidence ransomware pre-encryption indicator.
Data Sources
Required Tables
False Positives & Tuning
- System administrators using net use * /DELETE as part of documented drive mapping refresh procedures during patch windows or infrastructure maintenance
- Logon/logoff scripts managed through Group Policy that remove mapped drives on session end to prevent accumulation of stale connections
- Automated IT service management workflows (e.g., ServiceNow runbooks) that reset user environments by clearing drive mappings before re-provisioning
Other platforms for T1070.005
Testing Methodology
Validate this detection against 3 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 1Remove Specific Network Share Connection with net use /delete
Expected signal: Sysmon EventCode 1: net.exe process creation with 'use \\127.0.0.1\IPC$ /delete' command line. Windows Security Event ID 5140 (share accessed) and then no corresponding 5142 (share removed) since the share never fully established due to authentication. MDE DeviceProcessEvents captures both the mapping and deletion commands.
- Test 2Bulk Network Share Removal with net use * /DELETE
Expected signal: Sysmon EventCode 1: net.exe with '* /DELETE /Y' in command line. Windows Security Event ID 5140 may fire for each share that was disconnected. The wildcard (*) in the command line is a high-fidelity indicator of bulk share removal. MDE DeviceProcessEvents captures the full command including the * wildcard.
- Test 3Delete Network Share Registry History (MountPoints2 Cleanup)
Expected signal: reg.exe process creation with 'delete' and 'MountPoints2' in command line. Sysmon EventCode 12 (RegistryKeyDeleted) for HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2. Security Event ID 4657 if registry auditing is enabled for HKCU keys.
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