Prioritizing Exploitable CVEs: A Strategic Approach to Vulnerability Management

More than 40,000 new vulnerabilities (CVEs) were published in 2024, with over 60% categorized as “high” or “critical.” While this statistic is alarming, it is essential to evaluate how many of these vulnerabilities pose an actual risk to your environment.

The severity of vulnerabilities is typically assessed using scoring systems like CVSS, which evaluate severity based on technical criteria. However, these systems lack awareness of the specific configurations of your network, your implemented controls, and how you have fortified your critical assets. This oversight can lead to security teams diverting their focus towards high-scoring vulnerabilities that might already be mitigated by existing defenses, while neglecting less prominent issues that could be more exploitable.

This discussion highlights the shortcomings of traditional vulnerability prioritization methods and advocates for a more effective strategy: exposure validation. This approach helps security teams concentrate on vulnerabilities that are indeed exploitable in their unique environments.

The Limitations of “Critical” Vulnerabilities

Last year saw a 38% increase in vulnerability disclosures, with many security tools and platforms continuing to prioritize them based solely on standard CVSS and EPSS scores. However, these scores reflect global data and do not consider the specific context of your environment. A vulnerability that scores 9.8 does not necessarily indicate a critical risk for your organization, especially if your defenses—such as firewalls, endpoint detection and response (EDR), or intrusion prevention systems (IPS/IDS)—are capable of stopping the exploit. Conversely, a vulnerability classified as “medium” could actually pose a significant threat.

Furthermore, the rapid pace of weaponization is concerning: over half of the exploited vulnerabilities in early 2024 were converted into effective exploits soon after their public disclosure. Attackers are often quicker than defenders, and while new vulnerabilities make headlines, many breaches stem from older, well-known flaws that remain unpatched.

The main issue is not the discovery of vulnerabilities but rather the prioritization of risks.

Shortcomings of Traditional Scoring Systems

The conventional systems for assessing vulnerabilities operate along these lines:

– CVSS provides a severity rating based on access requirements, privileges, and potential impact.
– EPSS predicts the likelihood of exploitation informed by external threat intelligence.
– CISA KEV identifies known exploited vulnerabilities.

While these systems offer a broad perspective, they do not account for your particular environment. They cannot assess whether your IPS is capable of blocking an exploit or if a vulnerable system is critical to your operations. Consequently, they treat all networks homogenously, often leading to wasted resources on relatively inconsequential vulnerabilities due to misplaced urgency.

Understanding Exposure Validation

Exposure Validation revolutionizes the process by empirically testing whether a vulnerability is genuinely exploitable in your environment. This involves conducting controlled attack simulations using real-world tactics to determine if the full exploitation process can succeed against your defenses. If your security controls can thwart the attack, that is a positive outcome. If not, you gain critical insights on what requires attention.

The objective is clear: substitute assumptions with evidence. This enables you to prioritize fixing the vulnerabilities that matter most.

Integrating Technology: BAS and Automated Pen Tests

Exposure Validation employs two key non-disruptive tools:

1. Breach and Attack Simulation (BAS): This continuous evaluation process utilizes documented real-world tactics and malware behaviors to assess whether your EDR, SIEM, and firewalls are adequately equipped to handle both established and emerging threats.

2. Automated Penetration Testing: This method simulates the activities of a malicious insider with access to your environment, evaluating their potential for lateral movement, privilege escalation, and attempts to access sensitive resources. This approach allows your red team to concentrate on more complex or high-stakes attack vectors.

Together, these tools provide a clear understanding of the actual risks your organization faces, moving beyond theoretical possibilities.

Case Study: Reassessing a CVSS Score of 9.4

For example, consider a vulnerability flagged with a CVSS score of 9.4. Upon performing exposure validation, several factors are assessed:

– Public Exploit Assessment: A proof-of-concept exists but requires specific technical skills and conditions for successful exploitation, reducing the immediate threat level and adjusting the risk score downward.

– Defensive Capabilities: A review of existing security controls reveals they effectively prevent this exploit from succeeding, further lowering the risk score.

– Asset Importance Evaluation: If the affected asset lacks critical data or functionality, the risk score is adjusted yet again to reflect its lesser impact on overall operations.

Thus, while scanners may categorize this vulnerability as critical, exposure validation reveals the true nature of the risk, allowing teams to prioritize more pressing vulnerabilities.

Optimizing Vulnerability Prioritization

Picus Security’s Exposure Validation (EXV) solution empowers teams to move beyond superficial severity scores and focus on real threats. We integrate attack surface management, breach and attack simulation, and automated penetration testing, culminating in a risk score that reflects genuine conditions rather than worst-case scenarios.

This score incorporates three essential factors:

1. Is the vulnerability genuinely exploitable?
2. Are your existing controls effectively mitigating it?
3. Is the affected system critical to your organization and its daily functions?

By leveraging this context, teams can concentrate on what matters, resulting in a more efficient and actionable vulnerability management process.

Proven Results

Organizations employing exposure validation have observed substantial improvements. At Picus, we have witnessed partners reduce critical vulnerabilities from 63% to just 10% within the same environment and tools. This reduction stems from the verification of actual exploitability.

This strategic shift diminishes the time spent on patching, minimizes extraneous alerts, and enhances security teams’ ability to focus on real threats while ignoring the excess noise.

Conclusions

Not every vulnerability requires immediate remediation; it is imperative to address only those that present a legitimate risk. Exposure validation supports teams in transitioning from raw severity scores to informed decision-making, leading to superior prioritization, fortified defenses, and overall enhanced security.