VPN access restricted to known users + geo-locations
Demonstrate that VPN access is technically enforced to permit connections only from authenticated users originating from pre-approved geographic locations, and that unauthorized user accounts or connections from non-approved regions are systematically blocked.
Description
What this control does
This control restricts Virtual Private Network (VPN) access to authenticated users whose identities are pre-registered in the organization's identity management system and whose connection originates from approved geographic locations. The VPN concentrator or gateway evaluates each connection attempt against user authentication credentials (e.g., username/password, certificate, multi-factor token) and compares the source IP geolocation against a whitelist or blacklist of countries, regions, or IP ranges. This dual-layer restriction prevents unauthorized access from compromised credentials used outside expected operational territories and reduces the attack surface from threat actors operating from high-risk geographies.
Control objective
What auditing this proves
Demonstrate that VPN access is technically enforced to permit connections only from authenticated users originating from pre-approved geographic locations, and that unauthorized user accounts or connections from non-approved regions are systematically blocked.
Associated risks
Risks this control addresses
- Credential theft or compromise enabling adversaries from foreign or high-risk jurisdictions to access the internal network remotely
- Insider threat actors traveling to or operating from unauthorized countries bypassing geographic access policies
- Brute-force or credential-stuffing attacks originating from botnets distributed across multiple non-approved geographies
- Unauthorized third-party contractors or former employees retaining VPN credentials and connecting from unapproved locations
- State-sponsored threat actors leveraging stolen credentials to establish persistent remote access from adversarial nations
- Lateral movement and data exfiltration following successful VPN access from unmonitored or unapproved geographic regions
- Compliance violations related to data sovereignty or export control regulations when connections originate from restricted countries
Testing procedure
How an auditor verifies this control
- Obtain and review the current VPN access policy document specifying authorized user roles and approved geographic locations or IP ranges.
- Export the VPN gateway or concentrator configuration file showing user authentication settings, geolocation filtering rules, and IP whitelist/blacklist definitions.
- Request a current roster of all active VPN user accounts from the identity management system and cross-reference against authorized personnel lists.
- Examine VPN authentication logs for a sample period (minimum 30 days) and identify all unique usernames and source IP addresses that successfully connected.
- Perform geolocation lookups on sampled source IP addresses from the connection logs using a reputable IP geolocation service or database.
- Attempt a test VPN connection using valid credentials from a non-approved geographic location (via proxy or VPN exit node in a blocked country) and verify the connection is denied.
- Review access-denial logs or SIEM alerts for rejected VPN connection attempts originating from non-approved geographies within the sample period.
- Interview IT or network security personnel to confirm the process for updating the approved user list and geographic location whitelist, including change control records for recent modifications.
Where this control is tested