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CVE-2026-39808 IBM QRadar · QRadar

Detect Fortinet FortiSandbox OS Command Injection (CVE-2026-39808) in IBM QRadar

Detects potential exploitation of CVE-2026-39808, an OS command injection vulnerability (CWE-78) in Fortinet FortiSandbox that allows an authenticated or unauthenticated attacker to execute arbitrary OS commands via crafted requests to the FortiSandbox management interface. This vulnerability is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and is subject to BOD 26-04 remediation timelines. Detection focuses on anomalous shell/command execution patterns originating from FortiSandbox processes, suspicious HTTP requests to the management interface containing shell metacharacters, and unexpected child processes spawned by FortiSandbox web/API services observed via syslog, proxy, or EDR telemetry on adjacent/monitoring hosts.

MITRE ATT&CK

Tactic
Initial Access Execution

QRadar Detection Query

IBM QRadar (QRadar)
sql 
SELECT DATEFORMAT(devicetime, 'YYYY-MM-dd HH:mm:ss') AS EventTime, sourceip, destinationip, URL, "Log Source"
FROM events
WHERE LOGSOURCETYPENAME(devicetype) ILIKE '%Fortinet%'
  AND (URL ILIKE '%;%' OR URL ILIKE '%|%' OR URL ILIKE '%&&%' OR URL ILIKE '%wget%' OR URL ILIKE '%curl%' OR URL ILIKE '%/bin/sh%' OR URL ILIKE '%/bin/bash%')
  AND (URL ILIKE '%/api%' OR URL ILIKE '%/sys%' OR URL ILIKE '%/cgi-bin%')
LAST 24 HOURS
critical severity medium confidence

QRadar AQL search across Fortinet log sources for URLs to FortiSandbox API/management paths containing shell metacharacters or command-injection payload primitives.

Data Sources

Fortinet DSM eventsProxy/Firewall events

Required Tables

events

False Positives & Tuning

  • Internal vulnerability assessment scanning
  • Encoded characters in legitimate multi-part API calls
  • Misconfigured monitoring tools that URL-encode special characters unnecessarily

Other platforms for CVE-2026-39808

Microsoft Sentinel (KQL) Splunk (SPL) Elastic Security (Elastic) Sumo Logic CSE (Sumo) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1Simulate command injection payload via HTTP request

    Expected signal: Proxy/firewall log entry with RequestURL containing ';id' directed at a lab FortiSandbox API endpoint

  2. Test 2Simulate reverse-shell download attempt via injected command

    Expected signal: Decoded URL parameter containing '&&wget' pattern logged in proxy/CEF logs; potential outbound connection to LAB-C2 in network logs

  3. Test 3Simulate suspicious child process spawn from FortiSandbox-named parent

    Expected signal: EDR process-creation event showing ParentBaseFileName 'fsav_httpd' spawning /bin/bash with CommandLine containing the test string

Last updated: 2026-07-17 Research depth: standard
References (4)

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