Detect Exfiltration Over Bluetooth in CrowdStrike LogScale
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel. If the command and control network is a wired Internet connection, an adversary may opt to exfiltrate data using a Bluetooth communication channel. Adversaries may choose to do this if they have sufficient access and proximity. Bluetooth connections might not be secured or defended as well as the primary Internet-connected channel because it is not routed through the same enterprise network. Real-world examples include the Flame malware's BeetleJuice module, which transmitted encoded data over Bluetooth and acted as a Bluetooth beacon to identify nearby Bluetooth-enabled devices.
MITRE ATT&CK
- Tactic
- Exfiltration
- Sub-technique
- T1011.001 Exfiltration Over Bluetooth
- Canonical reference
- https://attack.mitre.org/techniques/T1011/001/
LogScale Detection Query
// T1011.001 - Exfiltration Over Bluetooth
// Covers: process execution, registry modification, and file write activity
#event_simpleName IN ("ProcessRollup2", "SyntheticProcessRollup2", "RegistryOperationEvent", "PeFileWritten", "NewExecutableWritten")
| case {
in("#event_simpleName", values=["ProcessRollup2", "SyntheticProcessRollup2"])
| FileName=/(?i)(btattach|btmgmt|hciconfig|hcitool|hcidump|bluetoothctl|sdptool|rfcomm|obexftp|obexd|bluetooth-sendto|fsquirt\.exe)/
OR CommandLine=/(?i)(bluetooth|rfcomm|obex|hcitool|hciconfig|btmgmt|bluetoothctl|bt-adapter|bluetoothd)/
| DetectionType:="Bluetooth Tool Execution";
#event_simpleName="RegistryOperationEvent"
| RegObjectName=/(?i)(bluetooth|bthport|bthenum|bthle|rfcomm|obex)/
| DetectionType:="Bluetooth Registry Modification";
in("#event_simpleName", values=["PeFileWritten", "NewExecutableWritten"])
| TargetFileName=/(?i)(bluetooth|rfcomm|obex|btooth)/
| DetectionType:="Bluetooth File Activity";
}
| table(
[_time, ComputerName, UserName, FileName, CommandLine,
RegObjectName, TargetFileName, ParentBaseFileName, DetectionType]
)
| sort(field=_time, order=desc)CrowdStrike LogScale (Falcon) query detecting T1011.001 Bluetooth exfiltration indicators using Falcon sensor telemetry. Uses a case block to classify events across three event types: ProcessRollup2 and SyntheticProcessRollup2 for Bluetooth tool execution matching FileName and CommandLine fields; RegistryOperationEvent for Bluetooth stack registry writes matching RegObjectName; and PeFileWritten/NewExecutableWritten for Bluetooth-related file creation matching TargetFileName. Each branch assigns a DetectionType label. Results are projected to a table with host, user, process, and indicator context fields for analyst review.
Data Sources
Required Tables
False Positives & Tuning
- Authorized IT support staff using Falcon-monitored endpoints to run btmgmt, hciconfig, or bluetoothctl for Bluetooth device troubleshooting or pairing, generating ProcessRollup2 matches under a known-good user account.
- CrowdStrike-protected developer workstations where obexftp, rfcomm, or sdptool are invoked as part of authorized Bluetooth stack testing for IoT or embedded product development.
- Windows device enrollment workflows where MDM agents trigger RegistryOperationEvent writes to BTHPORT or BTHENUM keys when Bluetooth adapters are initialized during endpoint provisioning.
- Automated compliance and audit scripts that enumerate Bluetooth registry keys via reg.exe or PowerShell, generating both ProcessRollup2 and RegistryOperationEvent hits simultaneously.
Other platforms for T1011.001
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 1Enumerate Bluetooth Devices on Windows
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe and CommandLine containing 'Get-PnpDevice' and 'Bluetooth'. PowerShell ScriptBlock Log Event ID 4104 with the full enumeration command. No registry modification events, but PnpDevice queries may appear in Windows Plug and Play logs.
- Test 2Linux Bluetooth Device Scan with hcitool
Expected signal: Linux auditd: execve syscall for hcitool with arguments 'scan' and 'lescan'. Syslog/daemon.log: bluetoothd activity logs showing scan initiation. If auditd is configured with execve monitoring: type=EXECVE msg= records with a0='hcitool' a1='scan'. Sysmon for Linux Event ID 1 if deployed.
- Test 3Transfer File via OBEX over Bluetooth on Linux
Expected signal: Linux auditd/Sysmon: execve event for obexftp with arguments including '--bluetooth', a MAC address, and '--put' with the file path. File creation event for /tmp/bt_test_exfil.txt. The process will exit with an error but telemetry is generated. Syslog may show bluetoothd connection attempt to the specified MAC address.
- Test 4Python Bluetooth Exfiltration Script Execution (Windows/Linux)
Expected signal: Sysmon Event ID 1: Process Create for python3.exe or python.exe with CommandLine referencing Bluetooth. Child process creation: powershell.exe spawned by python with 'Get-PnpDevice -Class Bluetooth'. Sysmon Event ID 1 for the child powershell.exe. PowerShell ScriptBlock Log Event ID 4104 for the enumeration command.
- Test 5Bluetooth Registry Key Inspection for Paired Devices
Expected signal: Sysmon Event ID 1: Process Create for reg.exe with query arguments targeting BTHPORT. If PowerShell fallback executes: Sysmon Event ID 1 for powershell.exe with BTHPORT in CommandLine. Sysmon Event ID 12 (Registry key access) for HKLM\SYSTEM\CurrentControlSet\Services\BTHPORT\Parameters\Devices. PowerShell ScriptBlock Log Event ID 4104.
References (10)
- https://attack.mitre.org/techniques/T1011/001/
- https://attack.mitre.org/software/S0143/
- https://securelist.com/the-flame-questions-and-answers/34344/
- https://docs.microsoft.com/en-us/windows-hardware/drivers/bluetooth/bluetooth-host-radio-support
- https://www.bluetooth.com/learn-about-bluetooth/tech-overview/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1011.001/T1011.001.md
- https://learn.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/interactive-logon-do-not-require-ctrl-alt-del
- https://www.stigviewer.com/stig/windows_10/2021-08-18/finding/V-220843
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceregistryevents-table
- https://www.sans.org/white-papers/bluetooth-security-overview/
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