Detect CVE-2025-14733: WatchGuard Firebox Out-of-Bounds Write Exploitation in Microsoft Sentinel
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
KQL Detection Query
let watchguard_mgmt_ports = dynamic([4117, 4118, 8080, 443]);
let timeframe = 24h;
union
(
CommonSecurityLog
| where TimeGenerated >= ago(timeframe)
| where DeviceVendor =~ "WatchGuard" or DeviceProduct =~ "Firebox"
| where Activity has_any ("crash", "exception", "core dump", "segfault", "out of bounds", "buffer", "overflow")
| project TimeGenerated, DeviceVendor, DeviceProduct, Activity, SourceIP, DestinationIP, DeviceAction, AdditionalExtensions
| extend AlertReason = "WatchGuard Firebox process anomaly indicative of memory corruption"
),
(
CommonSecurityLog
| where TimeGenerated >= ago(timeframe)
| where DeviceVendor =~ "WatchGuard" or DeviceProduct =~ "Firebox"
| where DestinationPort in (watchguard_mgmt_ports)
| where DeviceAction in~ ("deny", "reject", "drop") == false
| summarize ConnectionCount = count(), UniqueSourceIPs = dcount(SourceIP) by bin(TimeGenerated, 5m), DestinationIP, DestinationPort
| where ConnectionCount > 100 or UniqueSourceIPs > 20
| extend AlertReason = "High volume connections to WatchGuard management interface"
),
(
Syslog
| where TimeGenerated >= ago(timeframe)
| where ProcessName has_any ("wgagent", "wgrd", "wguard", "httpd", "wgpcc")
| where SyslogMessage has_any ("segfault", "SIGSEGV", "core dump", "out of bounds", "stack smashing", "buffer overflow", "heap corruption")
| project TimeGenerated, Computer, ProcessName, SyslogMessage
| extend AlertReason = "WatchGuard process crash or memory corruption signal"
)
| order by TimeGenerated descDetects WatchGuard Firebox exploitation attempts via process crash indicators, memory corruption signals in syslog, and anomalous management interface connection volumes consistent with CVE-2025-14733 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate high-volume administrative activity to Firebox management interfaces during maintenance windows
- Firmware update processes may trigger crash or restart log entries
- Security scanning tools performing authorized vulnerability assessments against the device
- Network monitoring solutions generating high connection counts to management ports
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.