# [HIGH] Modern VS Code extension development tutorial: Building a secure extension

**Source:** Snyk
**Published:** 2023-10-02
**Article:** https://snyk.io/blog/modern-vs-code-extension-development-tutorial/

## Threat Profile

Snyk Blog In this article
Written by Mdu Sibisi 
October 2, 2023
0 mins read The widespread success and influence of Microsoft Visual Studio (VS) Code can be largely credited to its extensibility. While it's often categorized as a code editor, with the right knowledge and extensions, it can be so much more. For instance, it can also be used as a web browser , word processor, or file-management system . Microsoft also encourages developers to take advantage of VS Code's extensibility by making th…

## 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

- **T1059.001** — PowerShell
- **T1027** — Obfuscated Files or Information
- **T1204.002** — User Execution: Malicious File

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### PowerShell encoded / obfuscated command

`UC_PS_OBFUSCATED` · phase: **exploit** · 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 IN ("powershell.exe","pwsh.exe")
      AND (Processes.process="*-enc *" OR Processes.process="*EncodedCommand*"
        OR Processes.process="*FromBase64String*" OR Processes.process="*-nop*"
        OR Processes.process="*-w hidden*" OR Processes.process="*Invoke-Expression*"
        OR Processes.process="*IEX(*" OR Processes.process="*DownloadString*"
        OR Processes.process="*Net.WebClient*")
    by Processes.dest, Processes.user, Processes.process_name, Processes.process, Processes.parent_process_name
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where FileName in~ ("powershell.exe","pwsh.exe")
| where ProcessCommandLine matches regex @"(?i)(-enc|encodedcommand|frombase64string|-nop|-w\s+hidden|invoke-expression|iex\s*\(|downloadstring|net\.webclient)"
| project Timestamp, DeviceName, AccountName, ProcessCommandLine,
          InitiatingProcessFileName, InitiatingProcessCommandLine
```

### Article-specific behavioural hunt — Modern VS Code extension development tutorial: Building a secure extension

`UC_1369_1` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — Modern VS Code extension development tutorial: Building a secure extension ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("node.js"))
    by Processes.dest, Processes.user, Processes.process_name,
       Processes.process, Processes.parent_process_name, Processes.process_path
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| append [
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_name IN ("node.js"))
    by Filesystem.dest, Filesystem.user, Filesystem.process_name,
       Filesystem.file_path, Filesystem.file_name
| `drop_dm_object_name(Filesystem)`
]
```

**Defender KQL:**
```kql
// Article-specific bespoke detection — Modern VS Code extension development tutorial: Building a secure extension
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where (FileName in~ ("node.js"))
| project Timestamp, DeviceName, AccountName, FileName,
          FolderPath, ProcessCommandLine,
          InitiatingProcessFileName, InitiatingProcessCommandLine
| order by Timestamp desc

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FileName in~ ("node.js"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```


## 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.