The Ultimate Guide to Troubleshooting Vulnerability Scan Failures

Vulnerability scans evaluate systems, networks, and applications to uncover security vulnerabilities. Leveraging databases of known vulnerabilities, these scans detect your weakest spots. These are the points most likely to be exploited by cybercriminals. Scans also help prioritize the order of importance in remediating and patching vulnerabilities.

Vulnerability assessment scans are critical for maintaining the security of your organization’s network and systems. But what do you do when the assessment fails? This guide will assist you in troubleshooting vulnerability scan failures and highlight PCI vulnerability scans.

The Ultimate Guide to Troubleshooting Vulnerability Scan Failures

Can a Vulnerability Scan Fail?

Yes, it’s possible for a vulnerability scan to “fail” in the sense that it does not meet the intended objectives or expectations. However, clarifying what ” failing ” means in a vulnerability scan is important, as it can vary depending on the context.

Note: A vulnerability scan failure does not usually imply that the organization has failed the test of securing its systems. Instead, it suggests that the test has encountered challenges or shortcomings that hinder its ability to fulfill its intended objectives effectively.

Here are some vulnerability scanning “failure” scenarios:

  1. Incomplete Scan: If a vulnerability scan fails to scan all targeted systems or assets within the specified scope, it may be deemed incomplete. This could occur due to network connectivity issues, misconfigured scan settings, or technical limitations of the scanning tool.
  1. Scan Errors or Failures: Technical issues or errors encountered during the scanning process can result in incomplete or inaccurate results. Examples include scan crashes, timeouts, or other software glitches that prevent the scan from completing successfully.
  1. Inaccurate Results: If the scan produces incorrect or misleading results, such as false positives or false negatives, it may fail to provide actionable insights into the security posture of the scanned systems. Inaccuracies could arise from misconfigurations, outdated vulnerability databases, or limitations of the scanning tool’s detection capabilities.
  1. Security or Compliance Violations: In some cases, vulnerability scans may be conducted to assess compliance with security standards or regulatory requirements. If the scan identifies security vulnerabilities or misconfigurations that violate these standards, the scan could be considered a failure from a compliance perspective. Of all these scenarios, this would be the only one where failure implies that you’ve failed a test.

Common Reasons for Scan Failures

Several factors can derail vulnerability scans:

  1. Network Connectivity Problems: Network issues obstruct scanning tools from accessing target systems.
  2. Misconfigured Scan Settings: Incorrect settings lead to incomplete or failed scans.
  3. Inadequate Access Permissions: Insufficient permissions to ensure thorough vulnerability assessments.
  4. Outdated Scanning Software: Obsolete software fails to detect new vulnerabilities and may encounter compatibility issues.
  5. Interference from Security Controls: Well-meaning security measures like firewalls might block scan traffic, impeding scans.

Troubleshooting Vulnerability Scan Failures

Addressing scan failures requires a systematic approach:

  1. Check Network Connectivity: Diagnose network issues and review network configurations.
  2. Review Scan Configurations: Ensure targets are correctly defined, adjust scan intensity, and validate custom scan options.
  3. Validate Access Permissions: Confirm scanner credentials and adjust permission settings on targets if needed.
  4. Update Scanning Software: Install updates regularly to incorporate new vulnerability signatures and ensure compatibility.
  5. Examine Security Controls: Review firewall rules and temporarily disable IPS features if necessary.
  6. Consult Logs and Documentation: Review scan logs and seek guidance from documentation and support resources.

Understanding PCI Vulnerability Scans

PCI vulnerability scans are mandated by the Payment Card Industry Data Security Standard (PCI DSS) to ensure compliance and protect sensitive cardholder data. These external vulnerabilty scans assess the security of systems and networks involved in processing credit card transactions, making them essential for businesses in the payment card industry.

Guide to Troubleshooting PCI Vulnerability Scan Failures

A. Network Configuration Issues

Scan failures often stem from network configuration issues, such as routing or segmentation issues. Ensure that your network infrastructure is properly configured to allow for comprehensive scanning coverage.

B. Firewall and Access Control Lists (ACLs)

Firewalls and ACLs can inadvertently block vulnerability scanners, leading to scan failures. Review firewall rules and ACL configurations to ensure that they permit scanning traffic from authorized sources.

C. Outdated Software

Vulnerability scan tools rely on up-to-date information to accurately identify security vulnerabilities. Ensure that your systems are regularly updated with the latest software patches to avoid false negatives caused by outdated vulnerability signatures.

D. Misconfigurations

System misconfigurations can obscure vulnerabilities or render scanning results inaccurate. Conduct regular audits of system configurations to identify and rectify misconfigurations that may interfere with vulnerability scans.

E. False Positives

False positives can inflate the number of reported vulnerabilities and obscure genuine security risks. Take the time to validate and verify scan findings to distinguish false positives from legitimate vulnerabilities.

F. Insufficient Credentials

Access credentials with inadequate privileges can limit the effectiveness of vulnerability scans. Provide vulnerability scanners with sufficient credentials to access and assess the security posture of target systems and applications.

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Regulatory Frameworks Requiring Vulnerability Scans

  1. PCI DSS (Payment Card Industry Data Security Standard)
  • Industry: Financial and Retail
  • Requirement: PCI DSS mandates regular vulnerability assessments for entities handling credit card information. This ensures the protection of cardholder data against unauthorized access and data breaches.
  1. NIST CSF (National Institute of Standards and Technology) Framework
  • Industry: General (Applicable across various sectors)
  • Requirement: NIST’s cybersecurity framework advocates for continuous vulnerability assessments and timely patching to enhance security resilience. It emphasizes identifying, protecting, detecting, responding, and recovering from cyber threats.
  1. CIS (Center for Internet Security) Controls
  • Industry: General
  • Requirement: CIS Controls prioritize actions to protect organizations and data from cyberattack vectors. Regular vulnerability scanning and patching are crucial components for maintaining security integrity.
  1. SOC 2 (Service Organization Control 2)
  • Industry: Service Providers
  • Requirement: SOC 2 focuses on security, availability, processing integrity, confidentiality, and customer data privacy. Vulnerability management programs, including periodic scanning and patching processes, are essential for safeguarding against threats.
  1. HIPAA (Health Insurance Portability and Accountability Act)
  • Industry: Healthcare
  • Requirement: HIPAA mandates the protection of patient health information through regular security assessments and the implementation of security measures to address vulnerabilities promptly.
  1. ISO/IEC 27001
  • Industry: General
  • Requirement: ISO/IEC 27001 outlines requirements for information security management systems. It necessitates regular vulnerability assessments and effective patch management to mitigate risks and ensure information confidentiality, integrity, and availability.
  1. GDPR (General Data Protection Regulation)
  • Industry: General (Applicable to organizations operating within or targeting EU citizens)
  • Requirement: GDPR mandates organizations to implement technical and organizational measures to ensure security appropriate to the risk. This includes regular vulnerability assessments and patch applications to protect personal data against breaches.
  1. FISMA (Federal Information Security Modernization Act)
  • Industry: Government Agencies
  • Requirement: FISMA mandates federal agencies to develop, document, and implement an agency-wide information security program. Vulnerability scanning is a critical component of this program to identify and mitigate security weaknesses in federal information systems.
  1. FERC (Federal Energy Regulatory Commission) Cyber Security Standards
  • Industry: Energy Sector
  • Requirement: FERC imposes cybersecurity standards on the energy sector to protect critical infrastructure. Vulnerability scanning is essential for identifying and mitigating risks to ensure the reliability and security of energy systems.

Post-Scan: How Are Vulnerabilities Prioritized? 

Prioritizing vulnerabilities is a critical aspect of effective cybersecurity management. Traditionally, the Common Vulnerability Scoring System (CVSS) has been widely used for this purpose. CVSS assigns a rating to each vulnerability on a scale from 1 to 10, considering factors such as the attack vector, exploit complexity, and impact on the system.

While CVSS provides a standardized way to rank vulnerabilities, it has limitations. Its static nature means that ratings remain unchanged even as new exploits emerge, and it lacks contextual information about specific infrastructure risks. To address these shortcomings, organizations often supplement CVSS with additional criteria.

One such approach is the Exploit Prediction Scoring System (EPSS), introduced in 2019. EPSS analyzes data on known Common Vulnerabilities and Exposures (CVEs) and their exploitation in real-world scenarios to predict the likelihood of future exploits. This model assigns a probability score from 0 to 1, with higher scores indicating a greater probability of exploitation within the next 30 days.

The EPSS strategy prioritizes vulnerabilities with higher CVSS ratings that have been previously exploited or have available proof of concept (PoC) exploits. Additionally, it recommends addressing lower-rated vulnerabilities that have already been exploited, as overlooking them could lead to significant risks.

In 2022, the US Federal Cybersecurity and Infrastructure Security Agency (CISA) issued recommendations for prioritizing vulnerabilities. These recommendations include considering factors such as the presence of an exploit, technical consequences of exploitation, automation complexity, impact on business processes, and potential harm.

Vulnerability Scan vs Penetration Test

The decision between vulnerability scans and penetration tests hinges on the desired outcome:

Vulnerability assessments scan infrastructure and uncover established vulnerabilities. These are valuable for routine checks, can be swiftly executed by less experienced personnel, and are crucial for detecting known weaknesses. However, they fall short in determining exploitability and potential damage.

Penetration tests are ideal for exploring vulnerabilities to validate their exploitability and assess the potential harm resulting from exploitation. Penetration tests can also reveal security gaps that are not classified as vulnerabilities. They provide a deeper understanding of an organization’s exposure to risks.

Centraleyes: Your Solution for Streamlined Compliance and Risk Management

Centraleyes revolutionizes the vulnerability management process by seamlessly integrating with top-tier scanning tools and providing a centralized hub for tracking and addressing vulnerabilities.

Gain unparalleled insight into your security posture with Centraleyes’ intuitive dashboard. It enables real-time visibility to prioritize and resolve vulnerabilities efficiently. By automating compliance tasks and simplifying risk management, Centraleyes empowers organizations to defend against cyber threats proactively, ensuring continuous compliance with industry standards and regulations.

Start Getting Value With
Centraleyes for Free

See for yourself how the Centraleyes platform exceeds anything an old GRC
system does and eliminates the need for manual processes and spreadsheets
to give you immediate value and run a full risk assessment in less than 30 days

Looking to learn more about Vulnerability Scan Failures?
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