✅ Title: CVSS, EPSS, and TALON SCORE: How to Prioritize Vulnerabilities?

As corporate digital assets expand, Attack Surface Management (ASM) has become a critical priority. However, determining which of the numerous vulnerabilities to remediate first remains a significant challenge. Moving away from the traditional approach of simply reducing the "vulnerability count," Risk-based Vulnerability Management (RBVM)—which identifies and responds to elements posing an actual threat to the organization—is now an essential strategy for modern security operations.

The core engine for realizing this strategy is Vulnerability Intelligence. Objective measurement of substantial threats and establishing a priority for action has become a key benchmark in security operations. We introduce the vulnerability assessment metrics primarily utilized in S2W's cyber threat intelligence platform, QUAXAR.

1. CVSS (Common Vulnerability Scoring System): How dangerous is the vulnerability?

CVSS is a universal standard metric that quantitatively evaluates the technical severity of software vulnerabilities on a scale of 0.0 to 10.0. It is frequently used as a common taxonomy by security teams worldwide and is categorized into ratings such as Low, Medium, High, and Critical for clear risk communication.

Calculation Method
The CVSS score is calculated based on the following metrics:
- Base Metrics: Evaluates intrinsic characteristics such as attack vector, complexity, and privileges required, as well as the impact on confidentiality, integrity, and availability.
- Temporal Metrics (Threat): Reflects factors that change over time, such as exploit code maturity or the distribution of official patches.
- Environmental Metrics: Considers the specific organizational infrastructure configuration and security control levels where the vulnerability exists.
- Supplemental Metrics: Newly introduced in v4.0 to provide additional context for response without affecting the final numerical score.

Limitations
- Lack of Business Context: It lacks consideration of an organization's specific threat environment or the business value of an asset. CVSS cannot distinguish between a financial core server and a general test server.
- Static Snapshots: It is merely a technical analysis at a specific point in time and does not update automatically as the threat landscape shifts, causing information to become outdated.
- Overlooking Chained Exploitation: It only scores individual vulnerabilities and does not consider the risk of an Attack Graph where multiple flaws are used sequentially.

2. EPSS (Exploit Prediction Scoring System): What is the probability of exploitation?

EPSS goes beyond static severity to provide a data-driven metric that predicts the probability (expressed as a value between 0.0 and 1.0) of a specific vulnerability being exploited in an actual attack within the next 30 days. It helps align priority based on the likelihood of becoming an actual target rather than just technical severity.

Calculation Method
Based on machine learning, it provides probability telemetry by synthesizing past attack data, public exploit code, and vulnerability attributes.

Limitations
- CVE Dependency: Only vulnerabilities with a CVE ID can be analyzed, potentially leaving gaps for zero-day threats or threats where a CVE ID has not been assigned.
- Governance and Interpretation: The data processing model and guidance for interpreting the output can be ambiguous, making it difficult for security personnel to reflect these figures in organizational security policies.

3. TALON SCORE: A multidimensional risk metric considering business context

TALON SCORE is a dynamic risk assessment metric calculated by S2W’s threat intelligence center, TALON. It goes beyond static metrics and statistical probabilities to provide optimized priority for corporate environments using in-depth vulnerability intelligence.

Calculation Method and Differentiators
- Reflecting Advanced Intelligence: It incorporates practical intelligence such as actual exploit cases and weaponization signals collected from the Deep & Dark Web and Telegram into the score.
- Optimized Response for the Organization: By analyzing risk from multiple angles and classifying it according to the organization's policies, it clarifies the response priority and enables rapid action.
- Empirical Verification (CART) Linkage: By integrating Continuous Automated Red Teaming (CART) functions, it supports strengthening the defense system by verifying vulnerabilities based on actual attack scenarios.

4. Conclusion:

Effective security operations start with accurate asset identification and vulnerability matching, and prioritization through multidimensional analysis is essential. Beyond just listing scores, organizations must understand the business context and prove the actual possibility of an attack. While CVSS and EPSS are useful indicators, an intelligence platform that integrates Attack Surface Management (ASM) and Account Takeover (ATO) monitoring is required to establish a definitive priority. This allows security organizations to clear away meaningless false alarms and concentrate their core capabilities only on the most critical attack vectors.

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*Discover more about QUAXAR, in the details below.