initial commit

1 files changed, 926 insertions, 0 deletions

diff --git a/internal/cvss/cvss.go b/internal/cvss/cvss.go
new file mode 100644
index 0000000..e50f718
--- /dev/null
+++ b/internal/cvss/cvss.go
@@ -0,0 +1,926 @@
+// CVSS vector parser.
+package cvss
+
+import (
+  "fmt"
+  "strings"
+)
+
+//go:generate stringer -linecomment -type=Version
+//go:generate stringer -linecomment -type=MetricCategory
+//go:generate stringer -linecomment -type=V2MetricKey
+//go:generate stringer -linecomment -type=V2Metric
+//go:generate stringer -linecomment -type=V3MetricKey
+//go:generate stringer -linecomment -type=V3Metric
+
+// CVSS version
+type Version byte
+
+const (
+  V20 Version = iota // 2.0
+  V30 // 3.0
+  V31 // 3.1
+)
+
+// CVSS metric category.
+type MetricCategory byte
+
+const (
+  Base MetricCategory = iota // Base
+  Temporal // Temporal
+  Environmental // Environmental
+)
+
+// CVSS metric key
+type V2MetricKey byte
+
+const (
+  V2AccessVector V2MetricKey = iota // AV
+  V2AccessComplexity // AC
+  V2Authentication // Au
+  V2ConfidentialityImpact // C
+  V2IntegrityImpact // I
+  V2AvailabilityImpact // A
+  V2Exploitability // E
+  V2RemediationLevel // RL
+  V2ReportConfidence // RC
+  V2CollateralDamagePotential // CDP
+  V2TargetDistribution // TD
+  V2ConfidentialityRequirement // CR
+  V2IntegrityRequirement // IR
+  V2AvailabilityRequirement // AR
+)
+
+// CVSS V2 metric key info lut
+var v2MetricKeys = map[V2MetricKey]struct {
+  Name string
+  Category MetricCategory
+} {
+  V2AccessVector: { "Access Vector", Base },
+  V2AccessComplexity: { "Access Complexity", Base },
+  V2Authentication: { "Authentication", Base },
+  V2ConfidentialityImpact: { "Confidentiality Impact", Base },
+  V2IntegrityImpact: { "Integrity Impact", Base },
+  V2AvailabilityImpact: { "Availability Impact", Base },
+  V2Exploitability: { "Exploitability", Temporal },
+  V2RemediationLevel: { "Remediation Level", Temporal },
+  V2ReportConfidence: { "Report Confidence", Temporal },
+  V2CollateralDamagePotential: { "Collateral Damage Potential", Environmental },
+  V2TargetDistribution: { "Target Distribution", Environmental },
+  V2ConfidentialityRequirement: { "Confidentiality Requirement", Environmental },
+  V2IntegrityRequirement: { "Integrity Requirement", Environmental },
+  V2AvailabilityRequirement: { "Availability Requirement", Environmental },
+}
+
+// v2 metric key IDs lut
+var v2MetricKeyIds = map[string]V2MetricKey {
+  "AV": V2AccessVector,
+  "AC": V2AccessComplexity,
+  "Au": V2Authentication,
+  "C": V2ConfidentialityImpact,
+  "I": V2IntegrityImpact,
+  "A": V2AvailabilityImpact,
+  "E": V2Exploitability,
+  "RL": V2RemediationLevel,
+  "RC": V2ReportConfidence,
+  "CDP": V2CollateralDamagePotential,
+  "TD": V2TargetDistribution,
+  "CR": V2ConfidentialityRequirement,
+  "IR": V2IntegrityRequirement,
+  "AR": V2AvailabilityRequirement,
+}
+
+// Get metric key from string.
+func GetV2MetricKeyFromString(s string) (V2MetricKey, error) {
+  k, ok := v2MetricKeyIds[s]
+  if ok {
+    return k, nil
+  } else {
+    return V2AccessVector, fmt.Errorf("unknown metric key: %s", s)
+  }
+}
+
+// Get metric key name.
+func (k V2MetricKey) Name() string {
+  return v2MetricKeys[k].Name
+}
+
+// Get metric key category.
+func (k V2MetricKey) Category() MetricCategory {
+  return v2MetricKeys[k].Category
+}
+
+// CVSS v2 metric value
+type V2Metric byte
+
+const (
+  V2AVNetwork V2Metric = iota // AV:N
+  V2AVAdjacentNetwork // AV:A
+  V2AVLocal // AV:L
+
+  V2ACLow // AC:L
+  V2ACMedium // AC:L
+  V2ACHigh // AC:H
+
+  V2AuMultiple // Au:M
+  V2AuSingle // Au:S
+  V2AuNone // Au:N
+
+  V2CNone // C:N
+  V2CPartial // C:P
+  V2CComplete // C:C
+
+  V2INone // I:N
+  V2IPartial // I:P
+  V2IComplete // I:C
+
+  V2ANone // A:N
+  V2APartial // A:P
+  V2AComplete // A:C
+
+  V2ENotDefined // E:ND
+  V2EUnproven // E:U
+  V2EProofOfConcept // E:POC
+  V2EFunctional // E:F
+  V2EHigh // E:H
+
+  V2RLOfficialFix // RL:OF
+  V2RLTemporaryFix // RL:TF
+  V2RLWorkaround // RL:W
+  V2RLUnavailable // RL:U
+  V2RLNotDefined // RL:ND
+
+  V2RCUnconfirmed // RC:UC
+  V2RCUncorroborated // RC:UR
+  V2RCConfirmed // RC:C
+  V2RCNotDefined // RC:ND
+
+  V2CDPNone // CDP:N
+  V2CDPLow // CDP:L
+  V2CDPLowMedium // CDP:LM
+  V2CDPMediumHigh // CDP:MH
+  V2CDPHigh // CDP:H
+  V2CDPNotDefined // CDP:ND
+
+  V2TDNone // TD:N
+  V2TDLow // TD:L
+  V2TDMedium // TD:M
+  V2TDHigh // TD:H
+  V2TDNotDefined // TD:ND
+
+  V2CRLow // CR:L
+  V2CRMedium // CR:M
+  V2CRHigh // CR:H
+  V2CRNotDefined // CR:ND
+
+  V2IRLow // IR:L
+  V2IRMedium // IR:M
+  V2IRHigh // IR:H
+  V2IRNotDefined // IR:ND
+
+  V2ARLow // AR:L
+  V2ARMedium // AR:M
+  V2ARHigh // AR:H
+  V2ARNotDefined // AR:ND
+)
+
+// map of metrics to metric keys
+var v2MetricKeyLut = map[V2Metric]V2MetricKey {
+  V2AVNetwork: V2AccessVector,
+  V2AVAdjacentNetwork: V2AccessVector,
+  V2AVLocal: V2AccessVector,
+
+  V2ACLow: V2AccessComplexity,
+  V2ACMedium: V2AccessComplexity,
+  V2ACHigh: V2AccessComplexity,
+
+  V2AuMultiple: V2Authentication,
+  V2AuSingle: V2Authentication,
+  V2AuNone: V2Authentication,
+
+  V2CNone: V2ConfidentialityImpact,
+  V2CPartial: V2ConfidentialityImpact,
+  V2CComplete: V2ConfidentialityImpact,
+
+  V2INone: V2IntegrityImpact,
+  V2IPartial: V2IntegrityImpact,
+  V2IComplete: V2IntegrityImpact,
+
+  V2ANone: V2AvailabilityImpact,
+  V2APartial: V2AvailabilityImpact,
+  V2AComplete: V2AvailabilityImpact,
+
+  V2ENotDefined: V2Exploitability,
+  V2EUnproven: V2Exploitability,
+  V2EProofOfConcept: V2Exploitability,
+  V2EFunctional: V2Exploitability,
+  V2EHigh: V2Exploitability,
+
+  V2RLOfficialFix: V2RemediationLevel,
+  V2RLTemporaryFix: V2RemediationLevel,
+  V2RLWorkaround: V2RemediationLevel,
+  V2RLUnavailable: V2RemediationLevel,
+  V2RLNotDefined: V2RemediationLevel,
+
+  V2RCUnconfirmed: V2ReportConfidence,
+  V2RCUncorroborated: V2ReportConfidence,
+  V2RCConfirmed: V2ReportConfidence,
+  V2RCNotDefined: V2ReportConfidence,
+
+  V2CDPNone: V2CollateralDamagePotential,
+  V2CDPLow: V2CollateralDamagePotential,
+  V2CDPLowMedium: V2CollateralDamagePotential,
+  V2CDPMediumHigh: V2CollateralDamagePotential,
+  V2CDPHigh: V2CollateralDamagePotential,
+  V2CDPNotDefined: V2CollateralDamagePotential,
+
+  V2TDNone: V2TargetDistribution,
+  V2TDLow: V2TargetDistribution,
+  V2TDMedium: V2TargetDistribution,
+  V2TDHigh: V2TargetDistribution,
+  V2TDNotDefined: V2TargetDistribution,
+
+  V2CRLow: V2ConfidentialityRequirement,
+  V2CRMedium: V2ConfidentialityRequirement,
+  V2CRHigh: V2ConfidentialityRequirement,
+  V2CRNotDefined: V2ConfidentialityRequirement,
+
+  V2IRLow: V2IntegrityRequirement,
+  V2IRMedium: V2IntegrityRequirement,
+  V2IRHigh: V2IntegrityRequirement,
+  V2IRNotDefined: V2IntegrityRequirement,
+
+  V2ARLow: V2AvailabilityRequirement,
+  V2ARMedium: V2AvailabilityRequirement,
+  V2ARHigh: V2AvailabilityRequirement,
+  V2ARNotDefined: V2AvailabilityRequirement,
+}
+
+// map of metric strings to metrics
+var v2MetricStrLut = map[string]V2Metric {
+  "AV:N": V2AVNetwork,
+  "AV:A": V2AVAdjacentNetwork,
+  "AV:L": V2AVLocal,
+
+  "AC:L": V2ACLow,
+  "AC:M": V2ACMedium,
+  "AC:H": V2ACHigh,
+
+  "Au:M": V2AuMultiple,
+  "Au:S": V2AuSingle,
+  "Au:N": V2AuNone,
+
+  "C:N": V2CNone,
+  "C:P": V2CPartial,
+  "C:C": V2CComplete,
+
+  "I:N": V2INone,
+  "I:P": V2IPartial,
+  "I:C": V2IComplete,
+
+  "A:N": V2ANone,
+  "A:P": V2APartial,
+  "A:C": V2AComplete,
+
+  "E:ND": V2ENotDefined,
+  "E:U": V2EUnproven,
+  "E:POC": V2EProofOfConcept,
+  "E:F": V2EFunctional,
+  "E:H": V2EHigh,
+
+  "RL:OF": V2RLOfficialFix,
+  "RL:TF": V2RLTemporaryFix,
+  "RL:W": V2RLWorkaround,
+  "RL:U": V2RLUnavailable,
+  "RL:ND": V2RLNotDefined,
+
+  "RC:UC": V2RCUnconfirmed,
+  "RC:UR": V2RCUncorroborated,
+  "RC:C": V2RCConfirmed,
+  "RC:ND": V2RCNotDefined,
+
+  "CDP:N": V2CDPNone,
+  "CDP:L": V2CDPLow,
+  "CDP:LM": V2CDPLowMedium,
+  "CDP:MH": V2CDPMediumHigh,
+  "CDP:H": V2CDPHigh,
+  "CDP:ND": V2CDPNotDefined,
+
+  "TD:N": V2TDNone,
+  "TD:L": V2TDLow,
+  "TD:M": V2TDMedium,
+  "TD:H": V2TDHigh,
+  "TD:ND": V2TDNotDefined,
+
+  "CR:L": V2CRLow,
+  "CR:M": V2CRMedium,
+  "CR:H": V2CRHigh,
+  "CR:ND": V2CRNotDefined,
+
+  "IR:L": V2IRLow,
+  "IR:M": V2IRMedium,
+  "IR:H": V2IRHigh,
+  "IR:ND": V2IRNotDefined,
+
+  "AR:L": V2ARLow,
+  "AR:M": V2ARMedium,
+  "AR:H": V2ARHigh,
+  "AR:ND": V2ARNotDefined,
+}
+
+// Convert string to CVSS 2.0 metric.
+func GetV2MetricFromString(s string) (V2Metric, error) {
+  // get metric
+  m, ok := v2MetricStrLut[s]
+  if !ok {
+    return V2AVNetwork, fmt.Errorf("invalid metric: %s", s)
+  }
+
+  // return success
+  return m, nil
+}
+
+// CVSS 2.0 vector.
+type v2Vector []V2Metric
+
+// Convert vector to string
+func (v v2Vector) String() string {
+  // convert to slice of metrics
+  metrics := []V2Metric(v)
+
+  // build vector
+  r := make([]string, len(metrics))
+  for i, m := range(metrics) {
+    r[i] = m.String()
+  }
+
+  // build and return string
+  return strings.Join(r, "/")
+}
+
+// Return CVSS version.
+func (v2Vector) Version() Version {
+  return V20
+}
+
+// create CVSS 2.0 vector from string
+func NewV2VectorFromString(s string) (Vector, error) {
+  strs := strings.Split(s, "/")
+  r := make([]V2Metric, len(strs))
+
+  // walk metric strings
+  for i, ms := range(strs) {
+    // convert string to vector
+    m, err := GetV2MetricFromString(ms)
+    if err != nil {
+      return nil, err
+    }
+
+    // add to results
+    r[i] = m
+  }
+
+  // build and return vector
+  return v2Vector(r), nil
+}
+
+// CVSS v3 metric key
+type V3MetricKey byte
+
+const (
+  V3AttackVector V3MetricKey = iota // AV
+  V3AttackComplexity // AC
+  V3PrivilegesRequired // PR
+  V3UserInteraction // UI
+  V3Scope // S
+  V3Confidentiality // C
+  V3Integrity // I
+  V3Availability // A
+  V3ExploitCodeMaturity // E
+  V3RemediationLevel // RL
+  V3ReportConfidence // RC
+  V3ConfidentialityRequirement // CR
+  V3IntegrityRequirement // IR
+  V3AvailabilityRequirement // AR
+  V3ModifiedAttackVector // MAV
+  V3ModifiedAttackComplexity // MAC
+  V3ModifiedPrivilegesRequired // MPR
+  V3ModifiedUserInteraction // MUI
+  V3ModifiedScope // MS
+  V3ModifiedConfidentiality // MC
+  V3ModifiedIntegrity // MI
+  V3ModifiedAvailability // MA
+)
+
+// CVSS V3 metric key info lut
+var v3MetricKeys = map[V3MetricKey]struct {
+  Name string
+  Category MetricCategory
+} {
+  V3AttackVector: { "Attack Vector", Base },
+  V3AttackComplexity: { "Attack Complexity", Base },
+  V3PrivilegesRequired: { "Privileges Required", Base },
+  V3UserInteraction: { "User Interaction", Base },
+  V3Scope: { "Scope", Base },
+  V3Confidentiality: { "Confidentiality", Base },
+  V3Integrity: { "Integrity", Base },
+  V3Availability: { "Availability", Base },
+  V3ExploitCodeMaturity: { "Exploit Code Maturity", Temporal },
+  V3RemediationLevel: { "Remediation Level", Temporal },
+  V3ReportConfidence: { "Report Confidence", Temporal },
+  V3ConfidentialityRequirement: { "Confidentiality Requirement", Environmental },
+  V3IntegrityRequirement: { "Integrity Requirement", Environmental },
+  V3AvailabilityRequirement: { "Availability Requirement", Environmental },
+  V3ModifiedAttackVector: { "Modified Attack Vector", Environmental },
+  V3ModifiedAttackComplexity: { "Modified Attack Complexity", Environmental },
+  V3ModifiedPrivilegesRequired: { "Modified Privileges Required", Environmental },
+  V3ModifiedUserInteraction: { "Modified User Interaction", Environmental },
+  V3ModifiedScope: { "Modified Scope", Environmental },
+  V3ModifiedConfidentiality: { "Modified Confidentiality", Environmental },
+  V3ModifiedIntegrity: { "Modified Integrity", Environmental },
+  V3ModifiedAvailability: { "Modified Availability", Environmental },
+}
+
+// metric key IDs lut
+var v3MetricKeyIds = map[string]V3MetricKey {
+  "AV": V3AttackVector,
+  "AC": V3AttackComplexity,
+  "PR": V3PrivilegesRequired,
+  "UI": V3UserInteraction,
+  "S": V3Scope,
+  "C": V3Confidentiality,
+  "I": V3Integrity,
+  "A": V3Availability,
+  "E": V3ExploitCodeMaturity,
+  "RL": V3RemediationLevel,
+  "RC": V3ReportConfidence,
+  "CR": V3ConfidentialityRequirement,
+  "IR": V3IntegrityRequirement,
+  "AR": V3AvailabilityRequirement,
+  "MAV": V3ModifiedAttackVector,
+  "MAC": V3ModifiedAttackComplexity,
+  "MPR": V3ModifiedPrivilegesRequired,
+  "MUI": V3ModifiedUserInteraction,
+  "MS": V3ModifiedScope,
+  "MC": V3ModifiedConfidentiality,
+  "MI": V3ModifiedIntegrity,
+  "MA": V3ModifiedAvailability,
+}
+
+// Get metric key from string.
+func GetV3MetricKeyFromString(s string) (V3MetricKey, error) {
+  k, ok := v3MetricKeyIds[s]
+  if ok {
+    return k, nil
+  } else {
+    return V3AttackVector, fmt.Errorf("unknown metric key: %s", s)
+  }
+}
+
+// Get metric key name.
+func (k V3MetricKey) Name() string {
+  return v3MetricKeys[k].Name
+}
+
+// Get metric key category.
+func (k V3MetricKey) Category() MetricCategory {
+  return v3MetricKeys[k].Category
+}
+
+// metric value
+type V3Metric byte
+
+const (
+  V3AVNetwork V3Metric = iota // AV:N
+  V3AVAdjacentNetwork // AV:A
+  V3AVLocal // AV:L
+  V3AVPhysical // AV:P
+
+  V3ACLow // AC:L
+  V3ACHigh // AC:H
+
+  V3PRNone // PR:N
+  V3PRLow // PR:L
+  V3PRHigh // PR:H
+
+  V3UINone // UI:N
+  V3UIRequired // UI:R
+
+  V3SUnchanged // S:U
+  V3SChanged // S:C
+
+  V3CHigh // C:H
+  V3CLow // C:L
+  V3CNone // C:N
+
+  V3IHigh // I:H
+  V3ILow // I:L
+  V3INone // I:N
+
+  V3AHigh // A:H
+  V3ALow // A:L
+  V3ANone // A:N
+
+  V3ENotDefined // E:X
+  V3EHigh // E:H
+  V3EFunctional // E:F
+  V3EProofOfConcept // E:P
+  V3EUnproven // E:U
+
+  V3RLNotDefined // RL:X
+  V3RLUnavailable // RL:U
+  V3RLWorkaround // RL:W
+  V3RLTemporaryFix // RL:T
+  V3RLOfficialFix // RL:O
+
+  V3RCNotDefined // RC:X
+  V3RCConfirmed // RC:C
+  V3RCReasonable // RC:R
+  V3RCUnknown // RC:U
+
+  V3CRNotDefined // CR:X
+  V3CRHigh // CR:H
+  V3CRMedium // CR:M
+  V3CRLow // CR:L
+
+  V3IRNotDefined // IR:X
+  V3IRHigh // IR:H
+  V3IRMedium // IR:M
+  V3IRLow // IR:L
+
+  V3ARNotDefined // AR:X
+  V3ARHigh // AR:H
+  V3ARMedium // AR:M
+  V3ARLow // AR:L
+
+  V3MAVNotDefined // MAV:X
+  V3MAVNetwork // MAV:N
+  V3MAVAdjacentNetwork // MAV:A
+  V3MAVLocal // MAV:L
+  V3MAVPhysical // MAV:P
+
+  V3MACNotDefined // MAC:X
+  V3MACLow // MAC:L
+  V3MACHigh // MAC:H
+
+  V3MMRNotDefined // MPR:X
+  V3MPRLow // MPR:L
+  V3MPRHigh // MPR:H
+
+  V3MUINotDefined // MUI:X
+  V3MUINone // MUI:N
+  V3MUIRequired // MUI:R
+
+  V3MSNotDefined // MMS:X
+  V3MSUnchanged // MMS:U
+  V3MSChanged // MMS:C
+
+  V3MCNotDefined // MC:X
+  V3MCHigh // MC:H
+  V3MCLow // MC:L
+  V3MCNone // MC:N
+
+  V3MINotDefined // MI:X
+  V3MIHigh // MI:H
+  V3MILow // MI:L
+  V3MINone // MI:N
+
+  V3MANotDefined // MA:X
+  V3MAHigh // MA:H
+  V3MALow // MA:L
+  V3MANone // MA:N
+  V3UnknownMetric // unknown
+)
+
+// map of metrics to metric keys
+var v3MetricKeyLut = map[V3Metric]V3MetricKey {
+  V3AVNetwork: V3AttackVector, // AV:N
+  V3AVAdjacentNetwork: V3AttackVector, // AV:A
+  V3AVLocal: V3AttackVector, // AV:L
+  V3AVPhysical: V3AttackVector, // AV:P
+
+  V3ACLow: V3AttackComplexity, // AC:L
+  V3ACHigh: V3AttackComplexity, // AC:H
+
+  V3PRNone: V3PrivilegesRequired, // PR:N
+  V3PRLow: V3PrivilegesRequired, // PR:L
+  V3PRHigh: V3PrivilegesRequired, // PR:H
+
+  V3UINone: V3UserInteraction, // UI:N
+  V3UIRequired: V3UserInteraction, // UI:R
+
+  V3SUnchanged: V3Scope, // S:U
+  V3SChanged: V3Scope, // S:C
+
+  V3CHigh: V3Confidentiality, // C:H
+  V3CLow: V3Confidentiality, // C:L
+  V3CNone: V3Confidentiality, // C:N
+
+  V3IHigh: V3Integrity, // I:H
+  V3ILow: V3Integrity, // I:L
+  V3INone: V3Integrity, // I:N
+
+  V3AHigh: V3Availability, // A:H
+  V3ALow: V3Availability, // A:L
+  V3ANone: V3Availability, // A:N
+
+  V3ENotDefined: V3ExploitCodeMaturity, // E:X
+  V3EHigh: V3ExploitCodeMaturity, // E:H
+  V3EFunctional: V3ExploitCodeMaturity, // E:F
+  V3EProofOfConcept: V3ExploitCodeMaturity, // E:P
+  V3EUnproven: V3ExploitCodeMaturity, // E:U
+
+  V3RLNotDefined: V3RemediationLevel, // RL:X
+  V3RLUnavailable: V3RemediationLevel, // RL:U
+  V3RLWorkaround: V3RemediationLevel, // RL:W
+  V3RLTemporaryFix: V3RemediationLevel, // RL:T
+  V3RLOfficialFix: V3RemediationLevel, // RL:O
+
+  V3RCNotDefined: V3ReportConfidence, // RC:X
+  V3RCConfirmed: V3ReportConfidence, // RC:C
+  V3RCReasonable: V3ReportConfidence, // RC:R
+  V3RCUnknown: V3ReportConfidence, // RC:U
+
+  V3CRNotDefined: V3ConfidentialityRequirement, // CR:X
+  V3CRHigh: V3ConfidentialityRequirement, // CR:H
+  V3CRMedium: V3ConfidentialityRequirement, // CR:M
+  V3CRLow: V3ConfidentialityRequirement, // CR:L
+
+  V3IRNotDefined: V3IntegrityRequirement, // IR:X
+  V3IRHigh: V3IntegrityRequirement, // IR:H
+  V3IRMedium: V3IntegrityRequirement, // IR:M
+  V3IRLow: V3IntegrityRequirement, // IR:L
+
+  V3ARNotDefined: V3AvailabilityRequirement, // AR:X
+  V3ARHigh: V3AvailabilityRequirement, // AR:H
+  V3ARMedium: V3AvailabilityRequirement, // AR:M
+  V3ARLow: V3AvailabilityRequirement, // AR:L
+
+  V3MAVNotDefined: V3ModifiedAttackVector, // MAV:X
+  V3MAVNetwork: V3ModifiedAttackVector, // MAV:N
+  V3MAVAdjacentNetwork: V3ModifiedAttackVector, // MAV:A
+  V3MAVLocal: V3ModifiedAttackVector, // MAV:L
+  V3MAVPhysical: V3ModifiedAttackVector, // MAV:P
+
+  V3MACNotDefined: V3ModifiedAttackComplexity, // MAC:X
+  V3MACLow: V3ModifiedAttackComplexity, // MAC:L
+  V3MACHigh: V3ModifiedAttackComplexity, // MAC:H
+
+  V3MMRNotDefined: V3ModifiedPrivilegesRequired, // MPR:X
+  V3MPRLow: V3ModifiedPrivilegesRequired, // MPR:L
+  V3MPRHigh: V3ModifiedPrivilegesRequired, // MPR:H
+
+  V3MUINotDefined: V3ModifiedUserInteraction, // MUI:X
+  V3MUINone: V3ModifiedUserInteraction, // MUI:N
+  V3MUIRequired: V3ModifiedUserInteraction, // MUI:R
+
+  V3MSNotDefined: V3ModifiedScope, // MMS:X
+  V3MSUnchanged: V3ModifiedConfidentiality, // MMS:U
+  V3MSChanged: V3ModifiedIntegrity, // MMS:C
+
+  V3MCNotDefined: V3ModifiedConfidentiality, // MC:X
+  V3MCHigh: V3ModifiedConfidentiality, // MC:H
+  V3MCLow: V3ModifiedConfidentiality, // MC:L
+  V3MCNone: V3ModifiedConfidentiality, // MC:N
+
+  V3MINotDefined: V3ModifiedIntegrity, // MI:X
+  V3MIHigh: V3ModifiedIntegrity, // MI:H
+  V3MILow: V3ModifiedIntegrity, // MI:L
+  V3MINone: V3ModifiedIntegrity, // MI:N
+
+  V3MANotDefined: V3ModifiedAvailability, // MA:X
+  V3MAHigh: V3ModifiedAvailability, // MA:H
+  V3MALow: V3ModifiedAvailability, // MA:L
+  V3MANone: V3ModifiedAvailability, // MA:N
+}
+
+// map of metric strings to metrics
+var v3MetricStrLut = map[string]V3Metric {
+  "AV:N": V3AVNetwork,
+  "AV:A": V3AVAdjacentNetwork,
+  "AV:L": V3AVLocal,
+  "AV:P": V3AVPhysical,
+
+  "AC:L": V3ACLow,
+  "AC:H": V3ACHigh,
+
+  "PR:N": V3PRNone,
+  "PR:L": V3PRLow,
+  "PR:H": V3PRHigh,
+
+  "UI:N": V3UINone,
+  "UI:R": V3UIRequired,
+
+  "S:U": V3SUnchanged,
+  "S:C": V3SChanged,
+
+  "C:H": V3CHigh,
+  "C:L": V3CLow,
+  "C:N": V3CNone,
+
+  "I:H": V3IHigh,
+  "I:L": V3ILow,
+  "I:N": V3INone,
+
+  "A:H": V3AHigh,
+  "A:L": V3ALow,
+  "A:N": V3ANone,
+
+  "E:X": V3ENotDefined,
+  "E:H": V3EHigh,
+  "E:F": V3EFunctional,
+  "E:P": V3EProofOfConcept,
+  "E:U": V3EUnproven,
+
+  "RL:X": V3RLNotDefined,
+  "RL:U": V3RLUnavailable,
+  "RL:W": V3RLWorkaround,
+  "RL:T": V3RLTemporaryFix,
+  "RL:O": V3RLOfficialFix,
+
+  "RC:X": V3RCNotDefined,
+  "RC:C": V3RCConfirmed,
+  "RC:R": V3RCReasonable,
+  "RC:U": V3RCUnknown,
+
+  "CR:X": V3CRNotDefined,
+  "CR:H": V3CRHigh,
+  "CR:M": V3CRMedium,
+  "CR:L": V3CRLow,
+
+  "IR:X": V3IRNotDefined,
+  "IR:H": V3IRHigh,
+  "IR:M": V3IRMedium,
+  "IR:L": V3IRLow,
+
+  "AR:X": V3ARNotDefined,
+  "AR:H": V3ARHigh,
+  "AR:M": V3ARMedium,
+  "AR:L": V3ARLow,
+
+  "MAV:X": V3MAVNotDefined,
+  "MAV:N": V3MAVNetwork,
+  "MAV:A": V3MAVAdjacentNetwork,
+  "MAV:L": V3MAVLocal,
+  "MAV:P": V3MAVPhysical,
+
+  "MAC:X": V3MACNotDefined,
+  "MAC:L": V3MACLow,
+  "MAC:H": V3MACHigh,
+
+  "MPR:X": V3MMRNotDefined,
+  "MPR:L": V3MPRLow,
+  "MPR:H": V3MPRHigh,
+
+  "MUI:X": V3MUINotDefined,
+  "MUI:N": V3MUINone,
+  "MUI:R": V3MUIRequired,
+
+  "MMS:X": V3MSNotDefined,
+  "MMS:U": V3MSUnchanged,
+  "MMS:C": V3MSChanged,
+
+  "MC:X": V3MCNotDefined,
+  "MC:H": V3MCHigh,
+  "MC:L": V3MCLow,
+  "MC:N": V3MCNone,
+
+  "MI:X": V3MINotDefined,
+  "MI:H": V3MIHigh,
+  "MI:L": V3MILow,
+  "MI:N": V3MINone,
+
+  "MA:X": V3MANotDefined,
+  "MA:H": V3MAHigh,
+  "MA:L": V3MALow,
+  "MA:N": V3MANone,
+}
+
+// Convert string to CVSS 3.1 metric.
+func GetV3MetricFromString(s string) (V3Metric, error) {
+  // get metric
+  m, ok := v3MetricStrLut[s]
+  if !ok {
+    return V3AVNetwork, fmt.Errorf("invalid metric: %s", s)
+  }
+
+  // return success
+  return m, nil
+}
+
+// CVSS v3.0 prefix
+var v30Prefix = "CVSS:3.0/"
+
+// CVSS 3.0 vector.
+type v30Vector []V3Metric
+
+// Convert vector to string
+func (v v30Vector) String() string {
+  // convert to slice of metrics
+  metrics := []V3Metric(v)
+
+  // build vector
+  r := make([]string, len(metrics))
+  for i, m := range(metrics) {
+    r[i] = m.String()
+  }
+
+  // build and return string
+  return v30Prefix + strings.Join(r, "/")
+}
+
+// Return CVSS version.
+func (v30Vector) Version() Version {
+  return V30
+}
+
+// create CVSS 3.0 vector from string
+func NewV30VectorFromString(s string) (Vector, error) {
+  strs := strings.Split(s, "/")
+  r := make([]V3Metric, len(strs))
+
+  // walk metric strings
+  for i, ms := range(strs) {
+    // convert string to vector
+    m, err := GetV3MetricFromString(ms)
+    if err != nil {
+      return nil, err
+    }
+
+    // add to results
+    r[i] = m
+  }
+
+  // build and return vector
+  return v30Vector(r), nil
+}
+
+// CVSS v3.1 prefix
+var v31Prefix = "CVSS:3.1/"
+
+// CVSS 3.1 vector.
+type v31Vector []V3Metric
+
+// Convert vector to string
+func (v v31Vector) String() string {
+  // convert to slice of metrics
+  metrics := []V3Metric(v)
+
+  // build vector
+  r := make([]string, len(metrics))
+  for i, m := range(metrics) {
+    r[i] = m.String()
+  }
+
+  // build and return string
+  return v31Prefix + strings.Join(r, "/")
+}
+
+// Return CVSS version.
+func (v31Vector) Version() Version {
+  return V31
+}
+
+// create CVSS 3.1 vector from string
+func NewV31VectorFromString(s string) (Vector, error) {
+  strs := strings.Split(s, "/")
+  r := make([]V3Metric, len(strs))
+
+  // walk metric strings
+  for i, ms := range(strs) {
+    // convert string to vector
+    m, err := GetV3MetricFromString(ms)
+    if err != nil {
+      return nil, err
+    }
+
+    // add to results
+    r[i] = m
+  }
+
+  // build and return vector
+  return v31Vector(r), nil
+}
+
+// CVSS vector
+type Vector interface {
+  // Get CVSS version.
+  Version() Version
+
+  // Get CVSS vector string.
+  String() string
+}
+
+// Create new CVSS vector from vector string.
+func NewVector(s string) (Vector, error) {
+  if len(s) > len(v31Prefix) && s[:len(v31Prefix)] == v31Prefix {
+    // create CVSS v2.0 vector.
+    return NewV31VectorFromString(s[len(v31Prefix):])
+  } else if len(s) > len(v30Prefix) && s[:len(v30Prefix)] == v30Prefix {
+    // create CVSS v3.0 vector.
+    return NewV30VectorFromString(s[len(v30Prefix):])
+  } else {
+    // create CVSS V2 vector
+    return NewV2VectorFromString(s)
+  }
+}