# T1553 - Subvert Trust Controls

## SOC Recommendation
Investigate Subvert Trust Controls activity in the context of Defense Impairment: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.

## D3FEND Mappings
| D3FEND Technique | Relationship | Practical SOC Action |
|---|---|---|
| Content Quarantine | Isolate | Apply Content Quarantine to contain the blast radius once this technique is observed. |
| Restore Configuration | Restore | Use Restore Configuration to recover affected systems or data after containment. |
| Configuration Inventory | Model | Use Configuration Inventory to establish a baseline that makes this technique's deviations easier to spot. |

## Investigation Steps
1. Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.
2. Check Sentinel analytics rules and incidents correlated with this technique.
3. Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource.

## Evidence to Collect
- Host or resource affected
- Account or identity involved
- Timestamp of the activity
- Related process, file, or network artifact
- Any preceding or follow-on alerts

## Response Actions
| Action | Risk | Automation Safe | Approval Required |
|---|---|---|---|
| Contain the affected host or account | Medium | No | Yes |
| Collect and preserve evidence | Low | Yes | No |

## KQL
```kql
// High Severity Weak Certificate Exposure Detected
let timeFrame = 5m;
CyfirmaASCertificatesAlerts_CL
| where severity == 'Critical' and TimeGenerated between (ago(timeFrame) .. now())
| extend
    Description=description,
    FirstSeen=first_seen,
    LastSeen=last_seen,
    ValidFrom=valid_from,
    ValidTo=valid_to,
    RiskScore=risk_score,
    Domain=sub_domain,
    TopDomain=top_domain,
    Protocols=protocols,
    SelfSigned=self_signed,
    AlertUID=alert_uid,
    UID=uid,
    CertificateData= cert_data,
    CertificateHash=cert_hash,
    IssuedBy=issued_by,
    IssuedTo=issued_to,
    ProviderName='CYFIRMA',
    ProductName='DeCYFIR/DeTCT'
| project
    TimeGenerated,
    Description,
    Domain,
    TopDomain,
    RiskScore,
    FirstSeen,
    LastSeen,
    ValidFrom,
    ValidTo,
    Protocols,
    SelfSigned,
    CertificateData,
    CertificateHash,
    IssuedBy,
    IssuedTo,
    ProviderName,
    ProductName
```
```kql
// High severity - Asset based Vulnerabilities
let timeFrame = 5m;
CyfirmaVulnerabilities_CL
| extend parsed = parse_json(extensions)
| extend extensionKeys = bag_keys(parsed)
| mv-expand extensionKeys
| extend extensionKeyStr = tostring(extensionKeys)
| extend ext = parsed[extensionKeyStr]
| extend props = ext.properties
| extend 
    attack_complexity         = tostring(props.attack_complexity),
    cvss_score                = toreal(props.cvss_score),
    integrity_impact          = tostring(props.integrity_impact),
    impact_score              = tostring(props.impact_score),
    attack_vector             = tostring(props.attack_vector),
    privileges_required       = tostring(props.privileges_required),
    cvss_version              = tostring(props.cvss_version),
    user_interaction          = tostring(props.user_interaction),
    cvss_vector               = tostring(props.cvss_vector),
    scope                     = tostring(props.scope),
    confidentiality_impact    = tostring(props.confidentiality_impact),
    exploitability_score      = toreal(props.exploitability_score),
    products                  = tostring(props.products),
    technologies              = tostring(props.technologies),
    vendors                   = tostring(props.vendors),
    confidence_score          = toint(confidence),
    servers                   = tostring(props.servers),
    vulnerability_type        = tostring(props.vulnerability_type),
    vulnerability_category        = tostring(props.vulnerability_category),
    NetworkIPs                = tostring(props.ips),
    ProviderName              ='CYFIRMA',
    ProductName               ='DeCYFIR/DeTCT'
| summarize arg_max(
                integrity_impact,
                TimeGenerated, 
                id,
                description,
                confidence_score,
                created,
                modified,
                attack_complexity,
                cvss_score,
                impact_score,
                attack_vector,
                privileges_required,
                cvss_version,
                user_interaction,
                cvss_vector,
                scope,
                confidentiality_impact,
                exploitability_score,
                products,
                technologies,
                vendors,
                ProviderName,
                ProductName,
                servers,
                NetworkIPs,
                vulnerability_type,
                vulnerability_category
            )
    by name
| where confidence_score >= 80 and vulnerability_category != 'ATTACK_SURFACE_VULNERABILITY' and TimeGenerated between (ago(timeFrame) .. now())
| project 
    TimeGenerated,
    name,
    confidence_score,
    integrity_impact,
    attack_complexity,
    cvss_score,
    impact_score,
    attack_vector,
    UID = id,
    description,
    created,
    modified,
    privileges_required,
    cvss_version,
    user_interaction,
    cvss_vector,
    scope,
    confidentiality_impact,
    exploitability_score,
    products,
    technologies,
    vendors,
    ProviderName,
    ProductName,
    servers,
    NetworkIPs,
    vulnerability_type,
    vulnerability_category
```
```kql
// High severity - Attack Surface based Vulnerabilities
let timeFrame= 5m;
CyfirmaVulnerabilities_CL
| extend parsed = parse_json(extensions)
| extend extensionKeys = bag_keys(parsed)
| mv-expand extensionKeys
| extend extensionKeyStr = tostring(extensionKeys)
| extend ext = parsed[extensionKeyStr]
| extend props = ext.properties
| extend 
    attack_complexity         = tostring(props.attack_complexity),
    cvss_score                = toreal(props.cvss_score),
    integrity_impact          = tostring(props.integrity_impact),
    impact_score              = tostring(props.impact_score),
    attack_vector             = tostring(props.attack_vector),
    privileges_required       = tostring(props.privileges_required),
    cvss_version              = tostring(props.cvss_version),
    user_interaction          = tostring(props.user_interaction),
    cvss_vector               = tostring(props.cvss_vector),
    scope                     = tostring(props.scope),
    confidentiality_impact    = tostring(props.confidentiality_impact),
    exploitability_score      = toreal(props.exploitability_score),
    products                  = tostring(props.products),
    technologies              = tostring(props.technologies),
    vendors                   = tostring(props.vendors),
    confidence_score          = toint(confidence),
    servers                   = tostring(props.servers),
    vulnerability_type        = tostring(props.vulnerability_type),
    vulnerability_category        = tostring(props.vulnerability_category),
    NetworkIPs                = tostring(props.ips),
    ProviderName              ='CYFIRMA',
    ProductName               ='DeCYFIR/DeTCT'
| summarize arg_max(
                integrity_impact,
                TimeGenerated, 
                id,
                description,
                confidence_score,
                created,
                modified,
                attack_complexity,
                cvss_score,
                impact_score,
                attack_vector,
                privileges_required,
                cvss_version,
                user_interaction,
                cvss_vector,
                scope,
                confidentiality_impact,
                exploitability_score,
                products,
                technologies,
                vendors,
                ProviderName,
                ProductName,
                servers,
                NetworkIPs,
                vulnerability_type,
                vulnerability_category
            )
    by name
| where confidence_score >= 80 and vulnerability_category == 'ATTACK_SURFACE_VULNERABILITY' and TimeGenerated between (ago(timeFrame) .. now())
| project 
    TimeGenerated,
    name,
    confidence_score,
    integrity_impact,
    attack_complexity,
    cvss_score,
    impact_score,
    attack_vector,
    UID = id,
    description,
    created,
    modified,
    privileges_required,
    cvss_version,
    user_interaction,
    cvss_vector,
    scope,
    confidentiality_impact,
    exploitability_score,
    products,
    technologies,
    vendors,
    ProviderName,
    ProductName,
    servers,
    NetworkIPs,
    vulnerability_type,
    vulnerability_category
```

## Escalation Criteria
- Subvert Trust Controls activity observed on a privileged account or critical system.
- Activity follows or precedes other suspicious behaviour in the same investigation.
- Automated triage cannot confidently rule out malicious intent.

## False Positive Considerations
- Legitimate administrative or maintenance activity matching this pattern.
- Approved security testing or red team exercise.
- Known benign software producing similar telemetry.

Generated by SOC Response Atlas by Basyrix.