# [CRIT] Miasma Worm Hits Microsoft Again: Azure Functions Action and 72 Other Repositories Disabled After Supply Chain Attack Targeting AI Coding Agents

**Source:** StepSecurity
**Published:** 2026-06-09
**Article:** https://www.stepsecurity.io/blog/miasma-worm-hits-microsoft-again-azure-functions-action-and-72-other-repositories-disabled-after-supply-chain-attack-targeting-ai-coding-agents

## Threat Profile

Back to Blog Threat Intel Miasma Worm Hits Microsoft Again: Azure Functions Action and 72 Other Repositories Disabled After Supply Chain Attack Targeting AI Coding Agents On June 5, 2026, the Miasma worm campaign reached Microsoft's Azure GitHub organizations. GitHub disabled 73 repositories across four Microsoft GitHub organizations after a malicious commit was pushed to the Azure/durabletask repository using a previously compromised contributor account. The attack planted configuration files t…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-45321`
- **Domain (defanged):** `check.git-service.com`
- **Domain (defanged):** `t.m-kosche.com`
- **Domain (defanged):** `git-service.com`

## MITRE ATT&CK Techniques

- **T1071.001** — Web Protocols
- **T1071.004** — DNS
- **T1071** — Application Layer Protocol
- **T1190** — Exploit Public-Facing Application
- **T1566.002** — Spearphishing Link
- **T1204.001** — User Execution: Malicious Link
- **T1059.001** — PowerShell
- **T1204.004** — User Execution: Malicious Copy and Paste
- **T1027** — Obfuscated Files or Information
- **T1195.002** — Compromise Software Supply Chain
- **T1204.002** — User Execution: Malicious File
- **T1546** — Event Triggered Execution
- **T1059.007** — JavaScript
- **T1071.001** — Application Layer Protocol: Web Protocols
- **T1041** — Exfiltration Over C2 Channel
- **T1568** — Dynamic Resolution
- **T1195.001** — Compromise Software Dependencies and Development Tools
- **T1078.004** — Valid Accounts: Cloud Accounts

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Malicious AI coding-agent hook configs written to repo (.claude/.gemini/.cursor/.vscode)

`UC_79_8` · phase: **install** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Filesystem.file_path) as paths from datamodel=Endpoint.Filesystem where (Filesystem.file_path="*\\.claude\\settings.json" OR Filesystem.file_path="*\\.gemini\\settings.json" OR Filesystem.file_path="*\\.cursor\\rules\\setup.mdc" OR Filesystem.file_path="*\\.vscode\\tasks.json" OR Filesystem.file_path="*\\.github\\setup.js") by Filesystem.dest Filesystem.user Filesystem.process_name | `drop_dm_object_name(Filesystem)` | where mvcount(paths)>=2
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where ActionType in ("FileCreated","FileModified")
| where FolderPath has_any (@"\.claude\settings.json", @"\.gemini\settings.json", @"\.cursor\rules\setup.mdc", @"\.vscode\tasks.json", @"\.github\setup.js")
| extend Artifact = case(
    FolderPath has @"\.claude\settings.json", "claude-hook",
    FolderPath has @"\.gemini\settings.json", "gemini-hook",
    FolderPath has @"\.cursor\rules\setup.mdc", "cursor-prompt-injection",
    FolderPath has @"\.vscode\tasks.json", "vscode-folderopen",
    FolderPath has @"\.github\setup.js", "miasma-payload", "other")
| summarize ArtifactsSeen = make_set(Artifact), Paths = make_set(FolderPath), FirstSeen = min(Timestamp) by DeviceId, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine
| where array_length(ArtifactsSeen) >= 2  // co-occurrence of >=2 of the 5 planted files
| order by FirstSeen desc
```

### node.exe spawned by Code/Cursor/Claude/Gemini executing .github/setup.js

`UC_79_9` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=node.exe (Processes.parent_process_name IN ("Code.exe","Cursor.exe","claude.exe","claude-code.exe","gemini.exe","node.exe")) (Processes.process="*.github\\setup.js*" OR Processes.process="*.github/setup.js*") by Processes.dest Processes.user Processes.parent_process_name Processes.process | `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName =~ "node.exe"
| where ProcessCommandLine has_any (@".github\setup.js", ".github/setup.js")
| where InitiatingProcessFileName in~ ("Code.exe","Cursor.exe","claude.exe","claude-code.exe","gemini.exe","node.exe","powershell.exe","cmd.exe")
| project Timestamp, DeviceName, AccountName,
          ParentImage = InitiatingProcessFolderPath,
          ParentCmd = InitiatingProcessCommandLine,
          ChildImage = FolderPath,
          ChildCmd = ProcessCommandLine,
          SHA256
| order by Timestamp desc
```

### Outbound DNS / HTTP to Miasma C2 (git-service.com / m-kosche.com)

`UC_79_10` · phase: **c2** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime values(DNS.src) as src values(DNS.query) as queries from datamodel=Network_Resolution.DNS where (DNS.query="*git-service.com" OR DNS.query="*m-kosche.com") by DNS.src DNS.dest | `drop_dm_object_name(DNS)`
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(30d)
| where RemoteUrl has_any ("git-service.com","m-kosche.com") or RemoteUrl in~ ("check.git-service.com","t.m-kosche.com","git-service.com")
| project Timestamp, DeviceName, AccountName = InitiatingProcessAccountName, InitiatingProcessFileName, InitiatingProcessCommandLine, RemoteUrl, RemoteIP, RemotePort
| order by Timestamp desc
```

### Suspicious commit pattern: '[skip ci]' with backdated timestamp adding only IDE config files

`UC_79_11` · phase: **delivery** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
`github_audit` action=git.push | spath input=raw_event | search commits{}.message="*[skip ci]*" (commits{}.added{}="*.claude/settings.json" OR commits{}.added{}="*.gemini/settings.json" OR commits{}.added{}="*.cursor/rules/setup.mdc" OR commits{}.added{}="*.vscode/tasks.json" OR commits{}.added{}="*.github/setup.js") | eval author_year=substr('commits{}.timestamp',1,4) | where author_year<"2024" | table _time repo actor commits{}.id commits{}.message commits{}.added{} author_year
```

**Defender KQL:**
```kql
CloudAppEvents
| where Timestamp > ago(30d)
| where Application == "GitHub"
| where ActionType in ("Repositories.Push","RepositoriesPush","git.push")
| extend Raw = tostring(RawEventData)
| where Raw has "[skip ci]"
| where Raw has_any (".claude/settings.json",".gemini/settings.json",".cursor/rules/setup.mdc",".vscode/tasks.json",".github/setup.js")
| extend AuthorDate = extract(@"author[^\d]+(\d{4})-\d{2}-\d{2}", 1, Raw)
| where isnotempty(AuthorDate) and toint(AuthorDate) < 2024
| project Timestamp, AccountDisplayName, AccountObjectId, IPAddress, ObjectName, AuthorDate, ActionType
| order by Timestamp desc
```

### 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
```

### Phishing-link click correlated to endpoint execution

`UC_PHISH_LINK` · phase: **delivery** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Phishing-link click that drives endpoint execution within 60s ```
| tstats `summariesonly` earliest(_time) AS click_time
    from datamodel=Web
    where Web.action="allowed"
    by Web.src, Web.user, Web.dest, Web.url
| `drop_dm_object_name(Web)`
| rename user AS recipient, dest AS clicked_domain, url AS clicked_url
| join type=inner recipient
    [| tstats `summariesonly` count
         from datamodel=Email.All_Email
         where All_Email.action="delivered" AND All_Email.url!="-"
         by All_Email.recipient, All_Email.src_user, All_Email.url, All_Email.subject
     | `drop_dm_object_name(All_Email)`
     | rex field=url "https?://(?<email_domain>[^/]+)"
     | rename recipient AS recipient]
| join type=inner src
    [| tstats `summariesonly` earliest(_time) AS exec_time
         values(Processes.process) AS exec_cmd, values(Processes.process_name) AS exec_proc
         from datamodel=Endpoint.Processes
         where Processes.parent_process_name IN ("chrome.exe","msedge.exe","firefox.exe",
                                                   "outlook.exe","brave.exe","arc.exe")
           AND Processes.process_name IN ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe",
                                            "rundll32.exe","regsvr32.exe","wscript.exe",
                                            "cscript.exe","bitsadmin.exe","certutil.exe",
                                            "curl.exe","wget.exe")
         by Processes.dest, Processes.user
     | `drop_dm_object_name(Processes)`
     | rename dest AS src]
| eval delta_sec = exec_time - click_time
| where delta_sec >= 0 AND delta_sec <= 60
| table click_time, exec_time, delta_sec, recipient, src, src_user, subject,
        clicked_domain, clicked_url, exec_proc, exec_cmd
| sort - click_time
```

**Defender KQL:**
```kql
// Phishing-link click that drives endpoint execution within 60s.
// Far higher fidelity than "every clicked URL" — most legitimate clicks
// never spawn a non-browser child process, so the join eliminates the
// 99% of noise that makes a raw click query unactionable.
let LookbackDays = 7d;
let SuspectClicks = UrlClickEvents
    | where Timestamp > ago(LookbackDays)
    | where AccountName !endswith "$"
    | where ActionType in ("ClickAllowed","ClickedThrough")
    | join kind=inner (
        EmailEvents
        | where Timestamp > ago(LookbackDays)
        | where DeliveryAction == "Delivered"
        | where EmailDirection == "Inbound"
        | project NetworkMessageId, Subject, SenderFromAddress, SenderFromDomain,
                  RecipientEmailAddress, EmailTimestamp = Timestamp
      ) on NetworkMessageId
    | join kind=leftouter (
        EmailUrlInfo | project NetworkMessageId, Url, UrlDomain
      ) on NetworkMessageId, Url
    | project ClickTime = Timestamp, AccountUpn, IPAddress, Url, UrlDomain,
              Subject, SenderFromAddress, SenderFromDomain, RecipientEmailAddress,
              ActionType;
// Correlate to a non-browser child process spawned within 60 seconds on
// the recipient's device.
DeviceProcessEvents
| where Timestamp > ago(LookbackDays)
| where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","firefox.exe",
                                         "outlook.exe","brave.exe","arc.exe")
| where FileName in~ ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe",
                        "rundll32.exe","regsvr32.exe","wscript.exe","cscript.exe",
                        "bitsadmin.exe","certutil.exe","curl.exe","wget.exe")
| join kind=inner SuspectClicks on $left.AccountName == $right.AccountUpn
| where Timestamp between (ClickTime .. ClickTime + 60s)
| project ClickTime, ProcessTime = Timestamp,
          DelaySec = datetime_diff('second', Timestamp, ClickTime),
          DeviceName, AccountName, RecipientEmailAddress, SenderFromAddress,
          Subject, Url, UrlDomain, ActionType,
          FileName, ProcessCommandLine, InitiatingProcessFileName
| order by ClickTime desc
```

### Fake CAPTCHA / clipboard-injected PowerShell (ClickFix / FakeCaptcha)

`UC_FAKECAPTCHA` · 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.parent_process_name IN ("explorer.exe","RuntimeBroker.exe")
      AND Processes.process_name IN ("powershell.exe","pwsh.exe","mshta.exe")
      AND (Processes.process="*iex*" OR Processes.process="*Invoke-Expression*"
        OR Processes.process="*FromBase64*" OR Processes.process="*DownloadString*"
        OR Processes.process="*hxxp*" OR Processes.process="*curl*" OR Processes.process="*wget*")
    by Processes.dest, Processes.user, Processes.process, Processes.parent_process_name
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where InitiatingProcessFileName in~ ("explorer.exe","RuntimeBroker.exe")
| where FileName in~ ("powershell.exe","pwsh.exe","mshta.exe")
| where ProcessCommandLine matches regex @"(?i)(iex|invoke-expression|frombase64|downloadstring|hxxp|curl |wget )"
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessCommandLine
```

### 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
```

### Trusted vendor binary / installer launching unusual children

`UC_SUPPLY_CHAIN` · phase: **exploit** · confidence: **Medium**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.parent_process_name IN ("setup.exe","installer.exe","update.exe")
      AND Processes.process_name IN ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
    by Processes.dest, Processes.user, Processes.parent_process_name, Processes.process_name, Processes.process
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where InitiatingProcessFileName in~ ("setup.exe","installer.exe","update.exe")
| where FileName in~ ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, FileName, ProcessCommandLine
```

### Article-specific behavioural hunt — Miasma Worm Hits Microsoft Again: Azure Functions Action and 72 Other Repositori

`UC_79_7` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — Miasma Worm Hits Microsoft Again: Azure Functions Action and 72 Other Repositori ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("setup.py","node.js","setup.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 ("setup.py","node.js","setup.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 — Miasma Worm Hits Microsoft Again: Azure Functions Action and 72 Other Repositori
// 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~ ("setup.py", "node.js", "setup.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~ ("setup.py", "node.js", "setup.js"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Network connections to article IPs / domains** ([template](../_TEMPLATES.md#network-ioc)) — phase: **c2**, confidence: **High**
  - IP / domain IOC(s): `check.git-service.com`, `t.m-kosche.com`, `git-service.com`

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-45321`


## Why this matters

Severity classified as **CRIT** based on: CVE present, IOCs present, 12 use case(s) fired, 18 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.