Outbreak: DEARCRY Infected File Detected on Host

Rule ID

PH_Rule_DEARCRY_InfectedFileHost

Default Status

Enabled

Description

DEARCRY Infected File was Detected on a Host

Severity

MITRE ATT&CK® Tactics

Exploit

MITRE ATT&CK® Techniques

No Technique Specified

Impacts

System

Data Source

FortiClient via Syslog, FortiSandbox via Syslog

Detection

Correlation

Remediation Guidance

Check if the source is patched for the CVE associated with the event. If yes then remove the host from the network and patch immediately. If host is not scanned then determine if the host is running the affected version of the application. If yes then patch immediately, else it is likely a false positive.

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.

DEARCRY

SubPattern Definitions

SubPattern Name: DEARCRY

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 CONTAIN "FortiClient" OR eventType CONTAIN "FortiSandbox") AND virusName IN ("W32/DearCry.OGE!tr","W32/DearCry.OGE!tr.ransom","W32/Filecoder.OGE!tr","PossibleThreat.ARN.H","W32/Encoder!tr","W32/Encoder.OGE!tr.ransom")

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

hostName,hostIpAddr

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=DEARCRY.hostName,
hostIpAddr=DEARCRY.hostIpAddr

FortiSIEM Rules