Detection rules › Splunk
Windows Alternate DataStream - Process Execution
The following analytic detects when a process attempts to execute a file from within an NTFS file system alternate data stream. This detection leverages process execution data from sources like Windows process monitoring or Sysmon Event ID 1, focusing on specific processes known for such behavior. This activity is significant because alternate data streams can be used by threat actors to hide malicious code, making it difficult to detect. If confirmed malicious, this could allow an attacker to execute hidden code, potentially leading to unauthorized actions and further compromise of the system.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Defense Evasion | T1564.004 Hide Artifacts: NTFS File Attributes |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Security-Auditing | 4688 | A new process has been created. |
Stages and Predicates
Stage 1: tstats
tstats WHERE Processes.parent_process_name!="unknown" Processes.process_name IN ("appvlp.exe", "bitsadmin.exe", "control.exe", "cscript.exe", "forfiles.exe", "ftp.exe", "mavinject.exe", "mshta.exe", "powershell.exe", "powershell_ise.exe", "pwsh.exe", "regini.exe", "regscr32.exe", "rundll32.exe", "sc.exe", "wmic.exe", "wscript.exe") BY Processes.action, Processes.dest, Processes.original_file_name, Processes.parent_process, Processes.parent_process_exec, Processes.parent_process_guid, Processes.parent_process_id, Processes.parent_process_name, Processes.parent_process_path, Processes.process, Processes.process_exec, Processes.process_guid, Processes.process_hash, Processes.process_id, Processes.process_integrity_level, Processes.process_name, Processes.process_path, Processes.user, Processes.user_id, Processes.vendor_product
Stage 2: search
search
Stage 3: regex
regex match(process, "(\b)\w+(\.\w+)?:\w+(\.\w{2,4})(?!\.)(\b|\s|&)")
Stage 4: search
search
Stage 5: search
search
Stage 6: search
search `macro`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Processes.parent_process_name | ne |
|
Processes.process_name | in |
|
process | regex_match |
|