# [CRIT] [GHSA / CRITICAL] CVE-2026-47731: NASA AMMOS Instrument Toolkit: Path traversal resulting in arbitrary file append (can be triggered over the network by unauthenticated attacker)

**Source:** GitHub Security Advisories
**Published:** 2026-06-05
**Article:** https://github.com/advisories/GHSA-p462-prxw-mjx4

## Threat Profile

NASA AMMOS Instrument Toolkit: Path traversal resulting in arbitrary file append (can be triggered over the network by unauthenticated attacker)

## 1. Summary

The Binary Stream Capture (BSC) component exposes an unauthenticated HTTP API for dynamically creating packet capture “handlers.” Because the code blindly trusts path‑related form fields, a remote client can:

- **Bypass the configured log root** and direct BSC to log to **arbitrary filesystem paths** (path traversal / directory escape),…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-47731`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1204.002** — User Execution: Malicious File
- **T1565.001** — Data Manipulation: Stored Data Manipulation
- **T1071.001** — Application Layer Protocol: Web Protocols
- **T1659** — Content Injection

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Unauthenticated POST to AIT-BSC /<name>/start with path-traversal form fields (CVE-2026-47731)

`UC_116_2` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as first_seen max(_time) as last_seen values(Web.url) as urls values(Web.http_user_agent) as user_agents from datamodel=Web where Web.http_method=POST AND (Web.uri_path="*/start" OR Web.url="*/start*") by Web.src Web.dest Web.uri_path Web.uri_query Web.url
| `drop_dm_object_name(Web)`
| where match(uri_path, "(?i)^/[^/]+/start$") AND (match(uri_query, "(?i)(log_dir_path|file_name_pattern|path)=") AND (match(uri_query, "(?i)(\.\.|%2e%2e|=%2[Ff]|=/etc/|=/home/|=/root/|=/var/|=/tmp/|=/usr/)") OR match(url, "(?i)(\.\.|%2e%2e)")))
| stats values(urls) as urls values(user_agents) as user_agents min(first_seen) as first_seen max(last_seen) as last_seen sum(count) as hits by src dest uri_path
| sort - last_seen
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(7d)
| where ActionType in ("InboundConnectionAccepted","ConnectionFound","ListeningConnectionCreated")
| where InitiatingProcessFileName matches regex @"(?i)^(python(3(\.\d+)?)?|ait-bsc)(\.exe)?$"
| where InitiatingProcessCommandLine has_any ("ait-bsc","ait.core.bsc","ait_bsc","StreamCaptureManagerServer","bsc.yaml")
| where RemoteIPType == "Public"
| summarize FirstSeen=min(Timestamp), LastSeen=max(Timestamp), Sessions=count(), AnyLocalPort=any(LocalPort) by DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, RemoteIP
| order by FirstSeen desc
```

### ait-bsc outbound TCP to public/non-baseline destination (attacker-supplied loc port)

`UC_116_3` · phase: **c2** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as first_seen max(_time) as last_seen sum(All_Traffic.bytes_out) as bytes_out values(All_Traffic.process) as processes from datamodel=Network_Traffic where (All_Traffic.process_name="python*" OR All_Traffic.process_name="ait-bsc*" OR All_Traffic.app="ait-bsc") AND All_Traffic.direction="outbound" AND NOT (All_Traffic.dest="10.0.0.0/8" OR All_Traffic.dest="172.16.0.0/12" OR All_Traffic.dest="192.168.0.0/16" OR All_Traffic.dest="127.0.0.0/8" OR All_Traffic.dest="169.254.0.0/16") by All_Traffic.src All_Traffic.dest All_Traffic.dest_port All_Traffic.transport All_Traffic.process_name
| `drop_dm_object_name(All_Traffic)`
| where match(mvjoin(processes, " "), "(?i)ait[-_.]?bsc|ait\.core\.bsc|StreamCaptureManager")
| stats min(first_seen) as first_seen max(last_seen) as last_seen sum(count) as sessions sum(bytes_out) as bytes_out values(processes) as processes by src dest dest_port transport process_name
| sort - first_seen
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName matches regex @"(?i)^(python(3(\.\d+)?)?|ait-bsc)(\.exe)?$"
| where InitiatingProcessCommandLine has_any ("ait-bsc","ait.core.bsc","ait_bsc","StreamCaptureManagerServer","bsc.yaml")
| where ActionType in ("ConnectionSuccess","ConnectionAttempt","ConnectionRequest")
| where RemoteIPType == "Public"
| summarize FirstSeen=min(Timestamp), LastSeen=max(Timestamp), Sessions=count(), DistinctRemotes=dcount(RemoteIP) by DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, RemoteIP, RemotePort
| order by FirstSeen desc
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-47731: NASA AMMOS Instrument Toolkit: Path traversal

`UC_116_1` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-47731: NASA AMMOS Instrument Toolkit: Path traversal ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("python_poc.py","attacker_tcp.py","dmc.py"))
    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_path="*/home/user/...*" OR Filesystem.file_path="*/home/elias/ait-venv/...*" OR Filesystem.file_path="*/home/elias/ait-venv/.../dmc.py*" OR Filesystem.file_path="*/var/opt/ait-bsc/logs*" OR Filesystem.file_path="*/usr/bin/env*" OR Filesystem.file_path="*/home/elias/ait-venv/lib/python3.10/site-packages/ait/core/*" OR Filesystem.file_name IN ("python_poc.py","attacker_tcp.py","dmc.py"))
    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 — [GHSA / CRITICAL] CVE-2026-47731: NASA AMMOS Instrument Toolkit: Path traversal
// 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~ ("python_poc.py", "attacker_tcp.py", "dmc.py"))
| 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 (FolderPath has_any ("/home/user/...", "/home/elias/ait-venv/...", "/home/elias/ait-venv/.../dmc.py", "/var/opt/ait-bsc/logs", "/usr/bin/env", "/home/elias/ait-venv/lib/python3.10/site-packages/ait/core/") or FileName in~ ("python_poc.py", "attacker_tcp.py", "dmc.py"))
| 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-2026-47731`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 4 use case(s) fired, 5 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.