# [CRIT] Breaking out of message brokers

**Source:** Snyk
**Published:** 2020-08-05
**Article:** https://snyk.io/blog/message-brokers/

## Threat Profile

Snyk Blog In this article
Written by Adam Goldschmidt 
August 5, 2020
0 mins read I recently reported two vulnerabilities in Apache Airflow—an open-source library that allows developers to programmatically author, schedule, and monitor workflows. Both of the vulnerabilities allow the attacker to change scope and gain privileges for a different machine, and they both rely on the attacker gaining access to the message broker before performing the attack.
In this blog post, I aim to show you why me…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2020-11982`
- **CVE:** `CVE-2020-11981`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1053.005** — Scheduled Task
- **T1204.002** — User Execution: Malicious File

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Scheduled task created with suspicious image / encoded args

`UC_SCHEDULED_TASK` · 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="schtasks.exe" AND Processes.process="*/create*"
      AND (Processes.process="*powershell*" OR Processes.process="*cmd.exe*"
        OR Processes.process="*rundll32*" OR Processes.process="*-enc*"
        OR Processes.process="*FromBase64*" OR Processes.process="*\Users\Public*"
        OR Processes.process="*\AppData\*")
    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 FileName =~ "schtasks.exe"
| where ProcessCommandLine has "/create"
| where ProcessCommandLine has_any ("powershell","cmd.exe","rundll32","-enc","FromBase64","\Users\Public","\AppData\")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName
```

### Article-specific behavioural hunt — Breaking out of message brokers

`UC_3016_2` · phase: **install** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — Breaking out of message brokers ```
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_path="*/etc/passwd*")
    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 — Breaking out of message brokers
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FolderPath has_any ("/etc/passwd"))
| 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.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2020-11982`, `CVE-2020-11981`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 3 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.