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Commerce Security Authority
Category: Vulnerability and Software Security

Authenticated Internal Scan

Also known as: Authenticated Internal Vulnerability Scan, Credentialed Internal Scan, Authenticated Scanning, Credentialed Scanning
Simply put

An authenticated internal scan is a security review of an organization's internal systems performed by logging in with valid credentials, rather than probing systems from the outside without access. Because the scan has trusted access, it can look deeper into each system and find weaknesses that would not be visible from an unauthenticated scan. It is one of the checks organizations use to identify vulnerabilities that need to be fixed.

Formal definition

An authenticated internal scan is an internal vulnerability scan conducted using valid, credentialed access to the target systems, enabling inspection of configurations, installed software, patch levels, and other host-level details that an unauthenticated scan cannot reach. Compared to unauthenticated scanning, credentialed access typically identifies a broader set of vulnerabilities and provides visibility into the actual state of systems, including weaknesses not externally observable. Within PCI DSS, authenticated internal vulnerability scanning is associated with internal scanning requirements (for example, the requirement often cited as 11.3.1.2 under PCI DSS v4.x); readers should confirm the exact requirement number, wording, and applicability against the current published version of the standard rather than assuming a fixed reference.

Why it matters

Unauthenticated scans see only what an outsider without credentials can observe, which means they can miss weaknesses that are only visible once a scanner logs into a host. Authenticated internal scans address this gap by using valid credentials to inspect the actual state of systems from the inside, allowing a deeper dive that can identify more vulnerabilities than an unauthenticated scan is able to reach. This matters because internal systems that appear hardened from an external vantage point may still carry outdated software, missing patches, or insecure configurations that only host-level access can reveal.

For organizations subject to PCI DSS, authenticated internal vulnerability scanning is associated with internal scanning requirements introduced under PCI DSS v4.x (a requirement often cited as 11.3.1.2). Because requirement numbering, wording, and applicability differ between versions, teams should confirm the exact reference against the current published standard rather than relying on a fixed number. Treating authenticated scanning as an assumed baseline rather than a discretionary add-on helps ensure that vulnerability management reflects the true condition of in-scope systems.

Authenticated internal scanning is one input into a broader vulnerability management program, not a standalone assurance of security. Its value depends on credential coverage, scan scope, and how findings are triaged and remediated. Deeper visibility can also surface a larger volume of findings, so results still require validation and prioritization; a scan that reports more vulnerabilities is providing more complete information, not necessarily indicating a worse security posture.

Who it's relevant to

Compliance officers and QSAs
Those assessing or attesting to PCI DSS need to understand that authenticated internal scanning is tied to internal scanning requirements under PCI DSS v4.x. Because the exact requirement number and wording can differ by version, confirm applicability against the current published standard when scoping assessments and reviewing evidence.
Vulnerability management and security engineering teams
These teams design and operate the scanning program, provision credentials with appropriate access, and ensure coverage across in-scope internal systems. They also triage the larger and more detailed set of findings that authenticated scans typically produce, distinguishing confirmed weaknesses from noise before remediation.
System and network administrators
Administrators maintain the hosts being scanned and act on findings related to patch levels, installed software, and configuration weaknesses that authenticated access can reveal. They are also involved in managing and safeguarding the credentials used for scanning.
Merchant and service provider risk teams
Organizations with cardholder data environments rely on authenticated internal scanning to gain visibility into the actual state of internal systems that may not be externally visible, supporting a defensible view of internal vulnerability exposure as part of their overall control program.

Inside Authenticated Internal Scan

Credentialed Access
An authenticated internal scan uses valid login credentials to access scanned hosts, allowing the scanner to inspect configuration, installed software, patch levels, and local settings that an unauthenticated scan cannot see.
Internal Vulnerability Scanning Scope
The scan is performed from within the internal network against systems in the cardholder data environment and connected systems, as distinct from external scans performed from outside the network perimeter.
Authentication Mechanism
Credentials or keys (such as local accounts, domain accounts, or SSH keys) provided to the scanning tool so it can log in to targets. These credentials are themselves sensitive and require protection and controlled handling.
Depth of Detection
Because it inspects the host from an authenticated perspective, this scan type is intended to identify a broader and more accurate set of vulnerabilities, missing patches, and misconfigurations than a non-credentialed scan, which typically relies on inference from network-exposed services.
PCI DSS Context
Internal vulnerability scanning is a control addressed within PCI DSS. Requirement numbering and wording differ between versions of the standard, so practitioners should confirm the applicable requirement and authenticated-scan expectations against the current published PCI DSS version rather than assuming a fixed requirement number.
Remediation and Rescan Cycle
Scan output supports a process of identifying, prioritizing, and remediating findings, followed by rescans intended to confirm that issues have been addressed.

Common questions

Answers to the questions practitioners most commonly ask about Authenticated Internal Scan.

Does an authenticated internal scan replace the need for penetration testing?
No. An authenticated internal scan and penetration testing serve different purposes and are not interchangeable. Authenticated internal scanning is a form of vulnerability scanning that logs into systems with valid credentials to enumerate missing patches, misconfigurations, and known vulnerabilities from an internal vantage point. Penetration testing is a distinct activity intended to actively exploit weaknesses and assess how they might be chained together. PCI DSS treats internal vulnerability scanning and penetration testing as separate requirements, and readers should confirm the specific requirements and wording against the current published version of the standard rather than assuming one satisfies the other.
Is an authenticated internal scan the same thing as an ASV external scan for PCI DSS?
No. These are different activities with different requirements. ASV (Approved Scanning Vendor) scans are external scans performed from outside the network by a vendor approved by the PCI Security Standards Council, and they follow a defined ASV validation process. Authenticated internal scans are performed from within the environment using valid credentials and are typically conducted by the organization itself or a qualified party. They address different perspectives on the same environment. Confirm which requirements govern internal versus external scanning, and how often each must occur, against the current published version of PCI DSS.
What credentials should be used for an authenticated internal scan?
An authenticated internal scan uses valid account credentials with sufficient privileges to log in to target systems and inspect installed software, patch levels, and configuration settings that are not visible to an unauthenticated scan. Credentials should be provisioned, protected, and managed in line with the access control and authentication controls defined in PCI DSS, and their use should be scoped to the systems being assessed. Because these accounts often carry elevated privileges, organizations should apply appropriate safeguards to how the credentials are stored, transmitted, and rotated.
Which systems should be included in the scope of an authenticated internal scan?
The scope should reflect the systems that fall within the cardholder data environment and any systems connected to or that could impact its security, consistent with how scope is defined in PCI DSS. Because authenticated scanning reveals internal detail such as installed packages and configuration, defining scope accurately is important. Readers should confirm the applicable scoping guidance and scanning requirements against the current published version of the standard, as wording and requirement numbering differ between versions.
How should the results of an authenticated internal scan be handled?
Findings should be reviewed, prioritized, and remediated according to the risk-ranking and remediation expectations in PCI DSS, with rescans performed as needed to confirm that issues have been addressed. Authenticated scans may surface a larger and more detailed set of findings than unauthenticated scans because they see inside the host, so triage helps distinguish issues requiring urgent action from lower-priority items. Confirm the specific remediation and re-scan requirements against the current published version of the standard.
What are the limitations of relying on authenticated internal scans?
Authenticated internal scans are intended to help identify known vulnerabilities and misconfigurations, but they have limits. They generally detect issues that appear in vulnerability signatures or configuration checks, so they may produce false positives or miss issues not covered by the scanner's checks. They do not actively exploit findings, do not by themselves demonstrate exploitability or attack chaining, and do not replace penetration testing, secure development practices, or ongoing monitoring. Scan quality also depends on correct credentials, coverage, and up-to-date checks, so results should be interpreted as one input among several security controls.

Common misconceptions

An authenticated internal scan is the same as an external ASV scan and can satisfy the same obligation.
Internal and external scanning address different vantage points and are treated separately. External scan expectations, including any Approved Scanning Vendor involvement, are distinct from internal scanning. Practitioners should confirm the specific scope and validation expectations for each against the current published PCI DSS version.
Running authenticated internal scans eliminates vulnerabilities and prevents compromise.
An authenticated scan is a detection control intended to help identify vulnerabilities and misconfigurations more accurately. It does not by itself remediate anything, and scanners can produce false positives and false negatives. Its value depends on remediation, rescanning, and coverage of in-scope systems.
Because the scanner logs in with credentials, those credentials are low risk and can be reused freely.
Scanning credentials often carry significant access and are sensitive in their own right. If mishandled they can expand risk rather than reduce it, so they require secure storage, least-privilege scoping, and controlled use.

Best practices

Confirm the applicable internal scanning and authenticated-scan expectations against the current published version of PCI DSS rather than relying on a fixed requirement number carried over from a prior version.
Ensure authenticated scans cover all in-scope systems in the cardholder data environment and connected systems, and periodically validate that scan coverage matches the defined scope.
Protect scanning credentials with least-privilege scoping, secure storage, and controlled handling, since these credentials are themselves sensitive and can expand risk if exposed.
Verify that authentication actually succeeded on each target, since a scan that silently falls back to unauthenticated access can miss vulnerabilities and give a false sense of completeness.
Operate a defined remediation and rescan cycle so identified findings are prioritized, addressed, and confirmed as resolved.
Account for scanner limitations by reviewing results for false positives and false negatives and correlating findings with other information rather than treating scan output as complete or definitive.