AWS EC2 Snapshot Attribute Modified

Rule ID

PH_Rule_ES_IMPORT_AWS_16

Default Status

Enabled

Description

An attempt was made to modify AWS EC2 snapshot attributes. Snapshots are sometimes shared by threat actors in order to exfiltrate bulk data from an EC2 fleet. If the permissions were modified, verify the snapshot was not shared with an unauthorized or unexpected AWS account.

Severity

MITRE ATT&CK® Tactics

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.

https://attack.mitre.org/tactics/TA0005

MITRE ATT&CK® Techniques

T1578.001

Modify Cloud Compute Infrastructure: Create Snapshot

An adversary may create a snapshot or data backup within a cloud account to evade defenses. By first Creating a Cloud Instance, mounting one or more created snapshots to that instance, and then applying a firewall policy that allows the adversary access to the created instance, an adversary can gain inbound and outbound SSH access.

https://attack.mitre.org/techniques/T1578/001

Impacts

Server

Data Source

AWS CloudTrail via AWS_CLOUDTRAIL

Detection

Correlation

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.

Filter

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 CONTAIN "AWS-CloudTrail-EC2-ModifySnapshotAttribute"

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

accountId,user

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

 accountId = Filter.accountId,
user = Filter.user

FortiSIEM Rules