Detection rules › Splunk

Command Line Homoglyphs - Windows (Sysmon)

Group by
_time, host
Source
github.com/anvilogic-forge/armory

Threat actors may use homoglyph attacks by substituting characters in process names or commands with visually similar Unicode symbols to impersonate legitimate commands, or messages (e.g., using Cyrillic “а” instead of Latin “a”). This tactic is often used to evade string-based detection and confuse analysts during investigation. This use case detects Windows processes containing Unicode characters from commonly abused homoglyph ranges, including Cyrillic extended, Greek extended, and full-width Latin letters and digits.

MITRE ATT&CK coverage

References

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

id: '44644.87462'
title: Command Line Homoglyphs - Windows
description: Threat actors may use homoglyph attacks by substituting characters in
  process names or commands with visually similar Unicode symbols to impersonate legitimate
  commands, or messages (e.g., using Cyrillic “а” instead of Latin “a”). This tactic
  is often used to evade string-based detection and confuse analysts during investigation.
  This use case detects Windows processes containing Unicode characters from commonly
  abused homoglyph ranges, including Cyrillic extended, Greek extended, and full-width
  Latin letters and digits.
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
  | regex process="[Ѐ-ӿͰ-Ͽa-zA-Z0-9]" | table _time, host, user, process, process_name,
  parent_process_name | bin span=1s | stats values(*) as * by _time, host '
techniques:
- defense-evasion:obfuscated files or information:command obfuscation
technique_id:
- T1027.010
data_category:
- Windows Sysmon
references:
- https://app.any.run/tasks/c044f84a-fd44-47ab-b53f-976debf96e63
- https://www.zdnet.com/article/magecart-group-uses-homoglyph-attacks-to-fool-you-into-visiting-malicious-websites/
- https://www.meshsecurity.io/blog/homoglyph-attacks-understanding-and-mitigating-the-threat
- https://www.bitdefender.com/en-us/blog/businessinsights/homograph-phishing-attacks-when-user-awareness-is-not-enough

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")

Stage 2: regex

| regex process="[Ѐ-ӿͰ-Ͽa-zA-Z0-9]"

Stage 3: table

| table _time, host, user, process, process_name, parent_process_name

Stage 4: bucket

| bin span=1s

Stage 5: stats

| stats values(*) as * by _time, host

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
EventCodeeq
  • 1 corpus 241 (splunk 225, kusto 15, elastic 1)
field:"EventID" kind:eq value:"1"
processregex_match
  • "[Ѐ-ӿͰ-Ͽa-zA-Z0-9]" corpus 2 (splunk 2)
field:"CommandLine" kind:regex_match

Search terms

These SPL tokens match against raw event text.

StageTerm
1"<EventID>1<"