OSSEC / HIDS Rule 81101

OSSEC / HIDS rule catalog

• Rule family: OSSEC / HIDS
• Rule ID: 81101
• Definition status: Present in current source
• Alert message / subject: Attached USB Storage
• Rule level: 3
• Definition checked: 2026-10-21

Interpretation and response

This event is recorded as “Attached USB Storage”. Review the originating log and the affected host or service to determine whether the activity was expected.

An OSSEC/HIDS event records or correlates activity. Blocking depends on the originating application and any separately configured Active Response policy; an alert alone does not prove that an attack was blocked.

Documentation

The following guidance was migrated from the historical wiki and reviewed against the rule definition. Legacy ASL product names and interface instructions refer to the versions documented then. Use the current metadata above and your installed configuration when interpreting thresholds, notification settings and response behavior.

Description

A new USB device has been attached to the system

What you should do

This means some USB device has been attached to the system. Review the alert to identify if this is an authorized connection.

Troubleshooting

False Positives

A legitimate event may still trigger this rule. Review the surrounding activity before deciding whether it is malicious.

Tuning Guidance

There is no guidance for tuning this rule.

Additional Information

Support

If you are unsure about how to respond to this alert, please contact Atomicorp support. We’re here to help you!

Source and revision

Migrated from HIDS_81101, wiki page 757, revision 6117 (20201021). Documentation review: 2026-10-21. An archived wiki status of Active is not a current deployment status.

For assistance, provide the rule ID, installed product and rule version, and a sanitized event to Atomicorp support .