FortiSIEM Rules

Uncommon Linux SSH Login

Rule ID


Default Status



Detects uncommon server logins that have not been seen in the LinuxSSHLogin lookup table. By default, the lookup table captures results for 1 day. This means that either user never logs in to the host.






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


Domain Policy Modification: Group Policy Modification

Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predicable network path \\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\.(Citation: TechNet Group Policy Basics)(Citation: ADSecurity GPO Persistence 2016)



Data Source

Login Data


Correlation Using Lookup Table

Remediation Guidance

No remediation guidance specified

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: Filter

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

eventType = "Generic_Unix_Successful_SSH_Login" AND LookupTableHas(LinuxSSHLogin_3,phCustId,reptDevName,user) = 0

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

 destName = Filter.reptDevName,
 user = Filter.user