FortiSIEM Rules

Agentless FIM: Audited file or directory ownership or permission changed

Rule ID


Default Status



FortiSIEM agentless file monitoring detected that a file or a directory ownership or permission changed






Defense Evasion

Defense Evasion consists of techniques that adversaries use to avoid detection throughout their compromise. Techniques used for defense evasion include uninstalling/disabling security software or obfuscating/encrypting data and scripts. Adversaries also leverage and abuse trusted processes to hide and masquerade their malware. Other tactics’ techniques are cross-listed here when those techniques include the added benefit of subverting defenses.

MITRE ATT&CK® Techniques


File and Directory Permissions Modification: Linux and Mac File and Directory Permissions Modification

Adversaries may modify file or directory permissions/attributes to evade access control lists (ACLs) and access protected files. Adversaries may use these commands to make themselves the owner of files and directories or change the mode if current permissions allow it. They could subsequently lock others out of the file. Specific file and directory modifications may be a required step for many techniques, such as establishing Persistence via .bash_profile and .bashrc or tainting/hijacking other instrumental binary/configuration files via Hijack Execution Flow.


Data Manipulation: Stored Data Manipulation

Adversaries may insert, delete, or manipulate data at rest in order to manipulate external outcomes or hide activity. Stored data could include a variety of file formats, such as Office files, databases, stored emails, and custom file formats. By manipulating stored data, adversaries may attempt to affect a business process, organizational understanding, and decision making.



Data Source

Any Device Agentless FIM via SSH



Remediation Guidance

Make sure it is an authorized change

Time Window

If the following pattern or patterns match an ingested event within the given time window in seconds, trigger an incident.

300 seconds

Trigger Conditions

If the following defined pattern/s occur within a 300 second time window.


SubPattern Definitions

SubPattern Name: FileChange

This is the named definition of the event query, this is important if multiple subpatterns are defined to distinguish them.

SubPattern Query

This is the query logic that matches incoming events


Group by Attributes

This defines how matching events are aggregated, only events with the same matching attribute values are grouped into one unique incident ID


Aggregate Constraint

This is most typically a numerical constraint that defines when the rule should trigger an incident

COUNT (*) >= 1

Incident Attribute Mapping

This section defines which fields in matching raw events should be mapped to the incident attributes in the resulting incident.

The available raw event attributes to map are limited to the group by attributes and the aggregate event constraint fields for each subpattern

 hostName = FileChange.hostName,
 fileName = FileChange.fileName,
 user = FileChange.user,
 userGrp = FileChange.userGrp,
 fileAccess = FileChange.fileAccess,
 preUser = FileChange.preUser,
 preFileAccess = FileChange.preFileAccess,
 preUserGrp = FileChange.preUserGrp