Concurrent Successful VPN Authentications To Same Account From Different Countries

Rule ID

PH_Rule_Access_65

Default Status

Enabled

Description

Detects simultaneous successful VPN authentications to the same account within a short period of time from different countries. This may indicate a stolen credential.

Severity

MITRE ATT&CK® Tactics

Credential Access

Credential Access consists of techniques for stealing credentials like account names and passwords. Techniques used to get credentials include keylogging or credential dumping. Using legitimate credentials can give adversaries access to systems, make them harder to detect, and provide the opportunity to create more accounts to help achieve their goals.

https://attack.mitre.org/tactics/TA0006

MITRE ATT&CK® Techniques

T1110.001

Brute Force: Password Guessing

Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.

https://attack.mitre.org/techniques/T1110/001

Impacts

Network

Data Source

FortiGate via Syslog, FortiProxy via Syslog, Palo Alto PAN-OS via Syslog, Juniper JunOS via Syslog, Juniper SSLVPN Via Syslog, Pulse Secure via Syslog, Hillstone Firewall Via Syslog, Cisco ASA via Syslog, Windows via OMI or FortiSIEM Agent, WatchGuard via Syslog, Sophos Firewall via Syslog, SonicOS via Syslog

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.

3600 seconds

Trigger Conditions

If the following defined pattern/s occur within a 3600 second time window.

VPNLogonDistinctCity

SubPattern Definitions

SubPattern Name: VPNLogonDistinctCity

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 IN (Group@PH_SYS_EVENT_VPNLogonSuccess) AND user IS NOT NULL AND user != "N/A" AND srcGeoCountry IS NOT NULL AND srcGeoCountry != "N/A"

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

user

Aggregate Constraint

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

COUNT(DISTINCT srcGeoCountry) >= 2

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

 user = VPNLogonDistinctCity.user

FortiSIEM Rules