Describe the behaviour you want to detect. SARA writes a starting Sigma rule with MITRE tags, false-positive guidance, and detection-engineering context. Anonymous, no account, best-effort generic detection.
title: CVE-2026-48908 Exploitation Attempt via API Webshell Payload
id: 828c5a47-0cd9-4d79-9eb1-c293d2d46ef6
status: experimental
description: >
Detects exploitation attempts against CVE-2026-48908, a CISA KEV-listed vulnerability.
This rule identifies characteristic command injection and webshell payloads targeting
the vulnerable API endpoint. This is a starting point — tune for your environment.
references:
- https://nvd.nist.gov/vuln/detail/CVE-2026-48908
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog
date: 2026-08-15
author: SARA Detection Engineering
tags:
- attack.t1190
- attack.t1059.004
logsource:
category: webserver
product: linux
detection:
selection_endpoint:
cs-method: POST
cs-uri-stem|contains|all:
- "/api/v2/admin/"
- "maintenance"
selection_payload:
cs-uri-query|contains:
- "cmd="
- "exec="
- "run="
- "payload="
sc-status: 200
filter_legit_admin:
cs-user-agent|contains:
- "InternalHealthMonitor/1.0"
- "CorpAdminBrowser/2.4"
condition: selection_endpoint and selection_payload and not 1 of filter_*
fields:
- c-ip
- cs-host
- cs-uri-stem
- cs-uri-query
- cs-user-agent
- sc-status
falsepositives:
- Legitimate administrative maintenance scripts using the API
- Internal vulnerability scanners running authorized assessments
level: high
Sigma is the open, vendor-neutral format for log-based detections. One rule, written once, converts to Splunk SPL, Elastic ES|QL, KQL for Microsoft Sentinel, Sumo, Chronicle, QRadar, and more. Detection engineers love it for the same reason ATT&CK is the lingua franca for tactics — Sigma is the lingua franca for the queries that detect them.
You've got a fresh write-up of a TTP and need a starting detection in your stack today. Generate, tune, ship.
Pair-program with SARA: the generator produces the skeleton, the engineer learns by tuning, the team commits the result.
You have a rule in one query language; describe it in English and get the Sigma version + conversions to every other backend.
Sketch a detection idea in 30 seconds before investing in a full DE sprint.
SARA Open ships an OpenAI-compatible API. Call POST /api/v1/sigma — Plain English in, valid Sigma YAML out, with MITRE tags and false-positive guidance.
curl -X POST https://sara-open.sirp.io/api/v1/sigma \
-H "Authorization: Bearer $SARA_API_KEY" \
-H "Content-Type: application/json" \
-d '{"description": "PowerShell encoded command from Office"}'
Read the API reference →