Understanding PCI DSS ASV External Scans: A Guide for Merchants
For businesses that accept credit and debit cards, the seemingly simple act of a customer swiping, tapping, or entering their card details triggers a complex chain of events — all underpinned by a critical, globally recognized security framework.
This framework is known as the Payment Card Industry Data Security Standard (PCI DSS) — a unified set of requirements designed to protect cardholder data.
For first-time merchants navigating this landscape, understanding PCI DSS — and the role of Approved Scanning Vendors (ASVs) — isn’t just about compliance. It’s the foundation for building trust and protecting the long-term viability of your business.
Why PCI DSS Exists — and Why It Matters
PCI DSS was developed in response to an escalating wave of data breaches. It defines a common set of technical and operational security requirements recognized by all major card brands. Compliance with PCI DSS isn’t optional; it’s mandated by the organizations that oversee payment processing, such as acquirers and payment brands.
Among these requirements, one stands out for its role in defending the edge of your network: Requirement 11.3.2 — External Vulnerability Scanning.
What Is an Approved Scanning Vendor (ASV)?
In the PCI ecosystem, ASVs are independent cybersecurity firms approved by the PCI Security Standards Council (PCI SSC). Their mandate is to conduct external vulnerability scans — security checks on your internet-facing systems to identify known weaknesses that could be exploited from outside your organization.
These scans aren’t penetration tests. They don’t involve exploiting vulnerabilities. But they are required quarterly for PCI DSS compliance, and must follow the rigorous procedures outlined in the official ASV Program Guide.
How an ASV Scan Works
The process typically follows a structured path:
Scoping: You define the assets to be scanned — all internet-facing IPs and domains that touch or support your cardholder data environment (CDE).
Scanning: The ASV uses a validated scanning solution to look for known vulnerabilities.
Reporting: You receive a formal report, summarizing findings and your compliance status.
Remediation: If vulnerabilities are found, you must resolve them and request a rescan.
Dispute Resolution: If you believe a finding is inaccurate or has a compensating control, you can challenge it — but only ASV-qualified personnel can adjudicate.
Final Report: Once a clean scan is achieved, the ASV issues an Attestation of Scan Compliance.
What Do ASV Scans Actually Detect?
ASV scans are designed to identify common external security risks, including:
Default credentials or configuration flaws
Insecure protocols or deprecated encryption standards (e.g., SSL, early TLS)
Open remote access services (e.g., SSH, VNC, Telnet)
Open database services accessible from the internet
Directory browsing on web servers
Weak cipher suites or certificate issues
Emerging threats like payment page scripts that execute in users' browsers
As of PCI DSS v4.0.1, these browser-executed scripts are under scrutiny. If discovered, the scan will include a Special Note to Scan Customer, requiring you to justify their business need and confirm that they are securely implemented — or confirm their removal.
This note does not automatically cause the scan to fail, but ignoring it may put you at risk when this best practice becomes mandatory after March 31, 2025.
Understanding the Scan Report
The ASV scan report includes:
A Summary: High-level pass/fail result
Vulnerability Details: List of findings, categorized by severity
An Attestation of Scan Compliance
For a passing scan, all "High" and "Medium" severity vulnerabilities must be remediated, and any configuration issues that violate PCI DSS must be addressed. You’re allowed to dispute findings or submit compensating controls — but they must be evaluated by certified ASV professionals.
What an ASV Scan Does Not Cover
Here’s where many first-time merchants get confused: a passing ASV scan does not mean you are PCI DSS compliant.
The scan fulfills only Requirement 11.3.2. Full compliance with PCI DSS involves addressing numerous other areas, including:
Access control and authentication
Change and patch management
Internal vulnerability scanning and penetration testing
Logging, monitoring, and incident response
Security awareness training
Third-party risk management for service providers who handle or influence cardholder data
For third-party service providers (TPSPs), there are specific obligations. You must obtain written agreements outlining their PCI responsibilities, perform due diligence, and monitor their compliance status.
How Do I Know If I Need to Engage a PCI SSC Approved Scanning Vendor (ASV)?
Whether your organization needs to engage a PCI SSC Approved Scanning Vendor (ASV) depends on your obligation to comply with PCI DSS Requirement 11.3.2, which specifically mandates external vulnerability scans.
Here’s how to determine if that applies to you:
The Requirement Comes from PCI DSS 11.3.2
This requirement mandates that external vulnerability scans be conducted at least once every three months — and only by an ASV approved by the PCI Security Standards Council (PCI SSC).It Applies to Merchants and Service Providers
Any merchant or service provider who is subject to PCI DSS compliance may be required to complete these external scans. In this context, these entities are known as Scan Customers.The Mandate Comes from Payment Brands and Acquirers
Your obligation to comply with PCI DSS — including engaging an ASV — doesn’t come from PCI SSC itself. Instead, it is determined by your payment brand (e.g., Visa, Mastercard) or acquiring bank. They decide whether you must validate compliance with PCI DSS, including performing ASV scans.Only a PCI SSC-Approved ASV Can Perform the Scan
If PCI DSS Requirement 11.3.2 applies to you, the external scans must be performed by an organization that is listed on the PCI SSC’s official list of Approved Scanning Vendors.
So, do you need an ASV?
If your acquiring bank or any payment brand you work with requires you to comply with PCI DSS — particularly Requirement 11.3.2 — then yes, you must engage an approved ASV and schedule quarterly external vulnerability scans.
To confirm this, contact your acquirer or the relevant payment brands directly. They will tell you whether PCI DSS compliance is mandatory for your business, based on your transaction volume, business model, and risk category.
In short: You need to engage an ASV if your payment partners require you to be PCI DSS compliant — and that includes quarterly external scans by an approved scanning vendor.
Final Thoughts: ASV Scans Are the Start — Not the Finish
An ASV scan is an essential part of PCI DSS compliance, but it’s only the tip of the iceberg. For merchants handling cardholder data, especially those new to compliance, it is a gateway requirement — one that affirms your commitment to data protection and begins your journey toward holistic security.
By working with a qualified ASV like AKATI Sekurity, you gain more than just a scan — you gain clarity, guidance, and assurance that your external digital footprint is being vigilantly monitored.
Because in the world of payment security, what you don’t know can hurt you. And what you do to prevent it makes all the difference.
