CVE-2025-14733 Microsoft Sentinel · KQL

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

Microsoft Sentinel (KQL)
kusto 
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 desc
critical severity medium confidence

Detects 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

CommonSecurityLogSyslogAzureActivity

Required Tables

CommonSecurityLogSyslog

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

Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) 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 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

  2. 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

  3. 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

Last updated: 2026-06-19 Research depth: standard
References (3)

Response Playbook

Triage

  1. Immediately verify whether affected WatchGuard Firebox devices have the latest firmware applied per WGSA-2025-00027 advisory. Cross-reference installed version against WatchGuard's patched releases.
  2. Identify all WatchGuard Firebox devices in the environment and their exposure level — determine which management interfaces (port 4117, 4118, 8080, 443) are internet-facing versus internal-only.
  3. Review Firebox device logs for crash events, unexpected process restarts, or abnormal terminations in the wgagent, wgrd, or httpd processes within the past 72 hours.
  4. Correlate source IPs of anomalous connections to management ports against threat intelligence feeds and check for repeat access patterns or scanning behavior.
  5. Determine if any post-exploitation indicators exist: new admin accounts, configuration changes, tunnels, or unexpected outbound connections from Firebox devices.

Containment

  1. Immediately restrict management interface access to known-good administrative IP ranges using ACLs or firewall rules, blocking all external/internet access to ports 4117, 4118, and 8080.
  2. If exploitation is confirmed or strongly suspected, isolate the affected Firebox device from the network by placing it in a quarantine VLAN or taking it offline, then bring up a backup or replacement device with the patched firmware.
  3. Rotate all WatchGuard administrative credentials including local admin accounts and any RADIUS/LDAP-integrated accounts used for device management.
  4. Block source IPs identified as exploitation actors at upstream network perimeter controls.

Evidence Collection

  1. Export full Firebox diagnostic logs, traffic logs, and event logs from the WatchGuard System Manager or web UI before any remediation steps that might overwrite them. Preserve timestamps and hash the archive.
  2. Capture network packet captures (PCAP) on spans/mirrors of management interfaces to preserve evidence of exploitation traffic, including any shellcode delivery or C2 callback patterns.
  3. Collect memory dumps or core dump files if the Firebox OS exposes them via diagnostic export — these may contain exploit payload artifacts useful for forensic analysis.

Escalation Criteria

  • !Escalate immediately to incident response leadership if post-exploitation indicators are found: new unauthorized admin accounts, configuration changes to VPN policies, route injection, or unexpected traffic tunneled through the device.
  • !Escalate to threat intelligence and executive leadership if the exploitation source is attributed to a nation-state actor or if multiple Firebox devices across the environment are simultaneously affected, indicating a coordinated campaign.

Investigation Guide

Related Techniques

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Forensic Artifacts

  • >WatchGuard Firebox event logs (available via WSM or web UI): crash events, admin login attempts, policy changes
  • >Core dump or diagnostic bundle files from affected Firebox devices (export via WatchGuard System Manager diagnostics)
  • >Network PCAP on management interface ports (4117, 4118, 8080, 443) capturing exploitation payload structure
  • >Syslog forwarded from Firebox to SIEM showing process termination events and kernel-level memory fault messages
  • >Active VPN tunnel listings and any newly created policies or routes that may indicate post-exploitation persistence

Tuning Guidance

Start by baselining normal administrative access patterns to WatchGuard management interfaces — document the expected source IP ranges, access times, and connection frequencies for your environment. Raise thresholds for connection-count anomaly alerts to reduce false positives from monitoring tools. For crash/process termination detections, suppress known-good maintenance windows using time-based filters. If your Firebox devices forward syslog, validate that the process names (wgagent, wgrd, wguard) match your specific firmware version's actual process names, as they may differ across versions. Prioritize alerts where both a crash indicator AND anomalous source IP activity occur within the same 30-minute window, as this compound condition has much higher fidelity for true exploitation.

Hunting Queries

Hunts for high-frequency source IPs interacting with WatchGuard management interfaces over the past 7 days, enriched with threat intelligence, to identify scanning or exploitation campaigns targeting CVE-2025-14733.

Hunting — KQL
kql 
CommonSecurityLog
| where DeviceVendor =~ "WatchGuard" or DeviceProduct =~ "Firebox"
| where TimeGenerated >= ago(7d)
| summarize EventCount = count(), FirstSeen = min(TimeGenerated), LastSeen = max(TimeGenerated) by SourceIP, Activity, DeviceAction
| where EventCount > 50
| join kind=leftouter (
    ThreatIntelligenceIndicator
    | where TimeGenerated >= ago(30d)
    | where isnotempty(NetworkIP)
    | summarize TI_Description = make_set(Description) by NetworkIP
  ) on $left.SourceIP == $right.NetworkIP
| order by EventCount desc
Hunting — SPL
spl 
index=* sourcetype=watchguard earliest=-7d
| stats count AS event_count, earliest(_time) AS first_seen, latest(_time) AS last_seen BY src_ip, action, dest_port
| where event_count > 50
| eval risk_score = case(dest_port IN (4117, 4118, 8080), event_count * 2, dest_port == 443, event_count * 1.5, true(), event_count)
| sort -risk_score
| head 100

Atomic Red Team Tests

Test 1 Simulate WatchGuard Management Interface Reconnaissance
linux

Simulates an attacker performing reconnaissance against WatchGuard Firebox management interfaces to identify exposed services prior to CVE-2025-14733 exploitation. Lab environment only.

Command

bash 
nmap -sV -p 4117,4118,8080,443 --script http-title,ssl-cert <TARGET_FIREBOX_IP> -oN /tmp/watchguard_recon.txt && cat /tmp/watchguard_recon.txt

Cleanup

bash 
rm -f /tmp/watchguard_recon.txt

Expected Telemetry

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

Expected Detection

KQL/SPL anomaly rules should trigger on connection volume to management ports; network IDS should alert on service fingerprinting activity

Test 2 Malformed HTTP Request to Firebox Management Interface
linux

Sends malformed or oversized HTTP requests to the WatchGuard Firebox management web interface to simulate memory corruption trigger conditions similar to CVE-2025-14733. Lab environment only with isolated test device.

Command

bash 
python3 -c "
import socket, time
target = '<TARGET_FIREBOX_IP>'
port = 8080
payload = b'GET /' + b'A' * 65536 + b' HTTP/1.1\r\nHost: ' + b'B' * 8192 + b'\r\nContent-Length: 99999\r\n\r\n' + b'C' * 32768
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(10)
try:
    s.connect((target, port))
    s.send(payload)
    response = s.recv(4096)
    print('Response:', response[:200])
except Exception as e:
    print('Exception (may indicate crash):', e)
finally:
    s.close()
"

Cleanup

bash 
No cleanup required; monitor target device for unexpected restart or crash

Expected Telemetry

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

Expected Detection

Process crash detection rules in SIEM should fire; anomaly detection on management interface should alert on malformed request patterns

Test 3 Post-Exploitation: Simulate Unauthorized Admin Account Creation Check
linux

After simulated Firebox compromise, checks whether unauthorized administrator accounts were created as a persistence mechanism — validates that detection of T1136 (Create Account) on network devices is functional.

Command

bash 
curl -sk -X POST https://<TARGET_FIREBOX_IP>:8080/admin/users \
  -H 'Content-Type: application/json' \
  -H 'Authorization: Bearer <TEST_TOKEN>' \
  -d '{"username": "test_backdoor_user", "role": "admin", "password": "TestP@ss123!"}' \
  -o /tmp/account_creation_response.json && cat /tmp/account_creation_response.json

Cleanup

bash 
curl -sk -X DELETE https://<TARGET_FIREBOX_IP>:8080/admin/users/test_backdoor_user -H 'Authorization: Bearer <TEST_TOKEN>'; rm -f /tmp/account_creation_response.json

Expected Telemetry

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

Expected Detection

Privileged account creation detection rules should fire; WatchGuard administrative audit trail should record the event for SIEM ingestion

Related Detections

Tactic Hubs

TA0001Initial AccessTA0002ExecutionTA0040Impact

Related Techniques

T1190Exploit Public-Facing ApplicationT1133External Remote ServicesT1498Network Denial of Service

Same Tactic: Initial Access

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