LoFP LoFP / false positives may occur in development or administrative environments where msxsl.exe is used for legitimate xml transformations. however, its use is uncommon in standard user activity and should be reviewed in most environments.

Techniques

Sample rules

Cisco NVM - Suspicious Network Connection Initiated via MsXsl

Description

This analytic identifies the use of msxsl.exe initiating a network connection to a non-private IP address. Although msxsl.exe is a legitimate Microsoft utility used to apply XSLT transformations, adversaries can abuse it to execute arbitrary code or load external resources in an evasive manner. This detection leverages Cisco NVM telemetry to identify potentially malicious use of msxsl.exe making network connections that may indicate command and control (C2) or data exfiltration activity.

Detection logic

`cisco_network_visibility_module_flowdata`
process_name = "msxsl.exe"
NOT dest IN (
        "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16", "100.64.0.0/10",
        "127.0.0.0/8", "169.254.0.0/16", "192.0.0.0/24", "192.0.0.0/29", "192.0.0.8/32",
        "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
        "192.31.196.0/24", "192.52.193.0/24", "192.88.99.0/24", "224.0.0.0/4", "192.175.48.0/24",
        "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1"
        )

| stats count min(_time) as firstTime max(_time) as lastTime
        values(parent_process_arguments) as parent_process_arguments
        values(process_arguments) as process_arguments
        values(parent_process_hash) as parent_process_hash
        values(process_hash) as process_hash
        values(module_name_list) as module_name_list
        values(module_hash_list) as module_hash_list
        values(dest_port) as dest_port
        values(aliul) as additional_logged_in_users_list
        values(dest_hostname) as dest_hostname
        by src dest parent_process_path parent_process_integrity_level process_path process_name process_integrity_level process_id transport

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| table
  parent_process_integrity_level parent_process_path parent_process_arguments parent_process_hash
  process_integrity_level process_path process_name process_arguments process_hash process_id
  additional_logged_in_users_list module_name_list module_hash_list
  src dest_hostname dest dest_port transport firstTime lastTime

| `cisco_nvm___suspicious_network_connection_initiated_via_msxsl_filter`