# [HIGH] Immutable infrastructure: Networks

**Source:** Snyk
**Published:** 2015-04-17
**Article:** https://snyk.io/blog/immutable-inf-networks/

## Threat Profile

Snyk Blog In this article
Written by Drew Wright 
April 17, 2015
0 mins read Editor's note This blog originally appeared on fugue.co. Fugue joined Snyk in 2022 and is a key component of Snyk IaC .
If you work with network infrastructure, you know that it has a tendency to grow warts, that is, it drifts from its original configuration. One of our goals in building  Fugue  as the operating system (OS) for the cloud and a single source of truth and trust for your infrastructure is to prevent this d…

## Indicators of Compromise (high-fidelity only)

- _No high-fidelity IOCs in the RSS summary._ If the source publishes a technical write-up with defanged IOCs in the body, those would be picked up automatically on the next pipeline run.

## MITRE ATT&CK Techniques

- **T1071.001** — Web Protocols
- **T1071.004** — DNS
- **T1543.003** — Windows Service

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Beaconing — periodic outbound to small set of destinations

`UC_BEACONING` · phase: **c2** · confidence: **Medium**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count, values(All_Traffic.dest_port) AS ports
    from datamodel=Network_Traffic.All_Traffic
    where All_Traffic.action="allowed" AND All_Traffic.dest_category!="internal"
    by _time span=10s, All_Traffic.src, All_Traffic.dest
| `drop_dm_object_name(All_Traffic)`
| streamstats current=f last(_time) AS prev_time by src, dest
| eval delta = _time - prev_time
| stats avg(delta) AS avg_delta stdev(delta) AS sd_delta count by src, dest
| where count > 30 AND sd_delta < 5 AND avg_delta>=30 AND avg_delta<=600
| sort - count
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(1d)
| where RemoteIPType == "Public" and ActionType == "ConnectionSuccess"
| project DeviceName, RemoteIP, RemotePort, Timestamp
| sort by DeviceName asc, RemoteIP asc, RemotePort asc, Timestamp asc
| extend prev_dev = prev(DeviceName, 1), prev_ip = prev(RemoteIP, 1),
         prev_port = prev(RemotePort, 1), prev_ts = prev(Timestamp, 1)
| where DeviceName == prev_dev and RemoteIP == prev_ip and RemotePort == prev_port
| extend delta_sec = datetime_diff('second', Timestamp, prev_ts)
| summarize conn_count = count(), avg_delta = avg(delta_sec), stdev_delta = stdev(delta_sec)
    by DeviceName, RemoteIP, RemotePort
| where conn_count > 30 and avg_delta between (30.0 .. 600.0) and stdev_delta < 5.0
| order by conn_count desc
```

### Service install for persistence — sc.exe / new service registry write

`UC_SERVICE_PERSIST` · phase: **install** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.process_name="sc.exe" AND Processes.process="*create*"
      AND (Processes.process="*\Users\*" OR Processes.process="*\AppData\*"
        OR Processes.process="*\ProgramData\*" OR Processes.process="*\Temp\*")
    by Processes.dest, Processes.user, Processes.process, Processes.parent_process_name
| `drop_dm_object_name(Processes)`
| append
    [| tstats `summariesonly` count from datamodel=Endpoint.Registry
        where Registry.registry_path="*\\SYSTEM\\CurrentControlSet\\Services\\*"
          AND Registry.registry_value_name="ImagePath"
          AND (Registry.registry_value_data="*\Users\*"
            OR Registry.registry_value_data="*\AppData\*"
            OR Registry.registry_value_data="*\Temp\*")
        by Registry.dest, Registry.registry_path, Registry.registry_value_data, Registry.user
     | `drop_dm_object_name(Registry)`]
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where FileName =~ "sc.exe" and ProcessCommandLine has "create"
| where ProcessCommandLine matches regex @"(?i)(\Users\|\AppData\|\ProgramData\|\Temp\)"
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName
```


## Why this matters

Severity classified as **HIGH** based on: 2 use case(s) fired, 3 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.