# T1046 - Network Service Discovery

## SOC Recommendation
Investigate Network Service Discovery activity in the context of Discovery: 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 |
|---|---|---|
| Network Traffic Analysis | Detect | Monitor for Network Traffic Analysis indicators relevant to this technique. |

## Investigation Steps
1. project Timestamp, RemoteIP, RemotePort, InitiatingProcessFileName

## 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 |
|---|---|---|---|
| If scanning from workstation: investigate immediately as com | Low | No | Yes |
| Block the scanning process if malicious | Medium | No | Yes |
| Correlate with lateral movement alerts (GEN-LM-001) | Low | No | Yes |

## KQL
```kql
DeviceNetworkEvents
| where TimeGenerated >= ago(10m)
| where ActionType == "ConnectionAttempted"
| where RemoteIP startswith "10." or RemoteIP startswith "192.168." or RemoteIP startswith "172."
| summarize
    StartTime = min(TimeGenerated),
    EndTime = max(TimeGenerated),
    UniqueIPs = dcount(RemoteIP),
    Ports = make_set(RemotePort, 20)
    by DeviceName, InitiatingProcessFileName, bin(TimeGenerated, 60s)
| where UniqueIPs > 30
| extend timestamp = StartTime, HostCustomEntity = DeviceName
| order by UniqueIPs desc
```
```kql
let HighRiskPorts = dynamic([3389,20,23,110,143,3306,8080,1433,9200,9300,25,445,135,21,1434,4333,5432,5500,5601,22,3000,5000,8088,8888]);
AWSSecurityHubFindings
| where RecordState == "ACTIVE" and ComplianceStatus == "FAILED"
| where tostring(AwsSecurityFindingGeneratorId) == "security-control/EC2.19"
      or tostring(ComplianceSecurityControlId) == "EC2.19"
| mv-expand Resource = Resources
| where tostring(Resource.Type) == "AwsEc2SecurityGroup"
| extend SGDetails = Resource.Details.AwsEc2SecurityGroup
| extend IpPermissions = SGDetails.IpPermissions
| mv-expand Perm = IpPermissions
| where toint(Perm.FromPort) in (HighRiskPorts)
| mv-expand Range = Perm.IpRanges
| where tostring(Range.CidrIp) in ("0.0.0.0/0", "::/0")
| summarize TimeGenerated = max(TimeGenerated), OpenHighRiskPorts = make_set(tostring(Perm.FromPort))
    by AwsAccountId, AwsRegion, AwsSecurityFindingTitle, AwsSecurityFindingDescription,
       AwsSecurityFindingId, ComplianceSecurityControlId, SecurityGroupId = tostring(SGDetails.GroupId), SecurityGroupARN = tostring(Resource.Id)
| extend OpenHighRiskPorts = strcat_array(OpenHighRiskPorts, ", ")
```
```kql
let Threshold = 3;
AGWFirewallLogs
| where Action == "Matched"
| where Message contains "Found User-Agent associated with security scanner"
| project TransactionId, Hostname, RequestUri, TimeGenerated, ClientIp, Message, DetailedMessage, DetailedData
| join kind = inner(
AGWFirewallLogs
| where Action == "Blocked"
) on TransactionId
| extend Uri = strcat(Hostname,RequestUri)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated), TransactionID = make_set(TransactionId), Message = make_set(Message), Detail_Message = make_set(DetailedMessage), Detail_Data = make_set(DetailedData), Total_TransactionId = dcount(TransactionId) by ClientIp, Uri, Action
| where Total_TransactionId >= Threshold
```

## Escalation Criteria
- Network Service Discovery 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
- Authorised vulnerability scanner (Nessus, Qualys) — Add scanner IP to discovery exclusions watchlist
- Network monitoring agents (PRTG, Zabbix, SolarWinds) — Exclude management server IP/hostname

Generated by SOC Response Atlas by Basyrix.