Detect CVE-2025-14733: WatchGuard Firebox Out-of-Bounds Write Exploitation in Splunk
Detects exploitation attempts targeting CVE-2025-14733, an out-of-bounds write vulnerability (CWE-787) in WatchGuard Firebox devices. This vulnerability is actively exploited in the wild (CISA KEV) and may allow remote code execution or device compromise. Detection focuses on anomalous management interface activity, unexpected process crashes, and network indicators consistent with exploitation.
MITRE ATT&CK
- Tactic
- Initial Access Execution Impact
SPL Detection Query
index=* sourcetype IN ("watchguard", "watchguard:firebox", "syslog", "cisco:asa")
(
(vendor="WatchGuard" OR product="Firebox" OR host="*firebox*")
AND (
(message IN ("*crash*", "*segfault*", "*SIGSEGV*", "*core dump*", "*out of bounds*", "*stack smashing*", "*buffer overflow*", "*heap corruption*"))
OR (process IN ("wgagent", "wgrd", "wguard", "httpd", "wgpcc") AND severity IN ("critical", "alert", "emergency"))
)
)
| eval alert_reason="WatchGuard Firebox memory corruption or crash indicator"
| eval threat_score=case(
match(message, "(?i)exploit|shellcode|payload|heap spray"), 90,
match(message, "(?i)segfault|SIGSEGV|core dump"), 75,
match(message, "(?i)crash|exception|overflow"), 60,
true(), 50
)
| table _time, host, src_ip, dest_ip, dest_port, message, alert_reason, threat_score
| sort -threat_score, -_time
| union
[search index=* sourcetype IN ("watchguard", "watchguard:firebox")
(vendor="WatchGuard" OR product="Firebox")
dest_port IN (443, 4117, 4118, 8080)
| bucket _time span=5m
| stats count AS conn_count, dc(src_ip) AS unique_sources BY _time, dest_ip, dest_port
| where conn_count > 100 OR unique_sources > 20
| eval alert_reason="High volume connections to WatchGuard management interface"
| eval threat_score=70]Identifies WatchGuard Firebox exploitation indicators including process crashes, memory corruption signals, and anomalous management interface traffic patterns associated with CVE-2025-14733.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Authorized vulnerability scanning or penetration testing against WatchGuard devices
- Firmware upgrade processes generating crash or restart events
- Load balancers or monitoring systems creating high connection counts to management ports
- Legitimate administrative sessions from multiple administrators during incident response
Other platforms for CVE-2025-14733
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.
- Test 1Simulate WatchGuard Management Interface Reconnaissance
Expected signal: Network connection logs showing SYN packets to ports 4117, 4118, 8080, and 443 from the attacker IP; IDS alerts on service enumeration; Firebox access logs showing connection attempts
- Test 2Malformed HTTP Request to Firebox Management Interface
Expected signal: Firebox crash or exception log entries; process termination events for web management daemon; syslog SIGSEGV or abnormal exit entries; network connection termination without proper HTTP response
- Test 3Post-Exploitation: Simulate Unauthorized Admin Account Creation Check
Expected signal: WatchGuard audit log entry for admin account creation; API access logs showing POST to user management endpoint; SIEM alert on privileged account creation on network device
Unlock Pro Content
Get the full detection package for CVE-2025-14733 including response playbook, investigation guide, and atomic red team tests.