LoFP LoFP / some legitimate users may run softether vpn for remote access or privacy purposes. exclude known approved vpn usage to reduce false alerts.

Techniques

Sample rules

Windows SoftEther VPN Masquerading as Legitimate Binary

Description

Flax Typhoon actors have been identified downloading and using SoftEther VPN software to obfuscate their activity. This searches for the SoftEther VPN binary running with the obfuscated binary names they use for the process.

Detection logic

`sysmon`
EventID=1
process IN (
    "*conhost.exe*",
    "*dllhost.exe*"
)
AND
(
    Company="*SoftEther*"
    OR
    OriginalFileName="vpnbridge*.exe"
)

| fillnull

| stats count min(_time) as firstTime
              max(_time) as lastTime
  by Computer EventID Company process action dest original_file_name
     parent_process parent_process_exec parent_process_guid parent_process_id
     parent_process_name parent_process_path process_hash process_integrity_level user
     user_id vendor_product


| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `windows_softether_vpn_masquerading_as_legitimate_binary_filter`