Detect Sangoma FreePBX Remote Admin Authentication Bypass (CVE-2019-19006) in Splunk
CVE-2019-19006 is an improper authentication vulnerability (CWE-287) in Sangoma FreePBX that allows remote unauthenticated attackers to bypass administrative authentication controls. This vulnerability is listed on CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. Successful exploitation grants attackers full administrative access to the FreePBX VoIP management interface, enabling call interception, configuration tampering, toll fraud, and potential lateral movement into the broader network.
MITRE ATT&CK
SPL Detection Query
index=web OR index=proxy OR index=network sourcetype IN (access_combined, apache:access, nginx:access, iis)
| rex field=uri_path "(?<admin_path>/admin/(?:config|ajax|page|modules)[^\s]*)"
| where isnotnull(admin_path)
| eval is_success=if(status IN ("200", "302"), 1, 0)
| where is_success=1
| eval src_ip=coalesce(src_ip, c_ip, clientip, X-Forwarded-For)
| eval user_agent=coalesce(useragent, http_user_agent, cs_User_Agent)
| stats
count as request_count,
values(admin_path) as accessed_paths,
values(status) as response_codes,
min(_time) as first_seen,
max(_time) as last_seen
by src_ip, user_agent
| eval severity=case(request_count > 20, "critical", request_count > 5, "high", true(), "medium")
| eval cve="CVE-2019-19006"
| eval product="Sangoma FreePBX"
| table _time, src_ip, user_agent, request_count, accessed_paths, response_codes, first_seen, last_seen, severity, cve, product
| sort - request_countDetects successful HTTP responses to FreePBX administrative paths which may indicate exploitation of the improper authentication vulnerability CVE-2019-19006.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Legitimate administrator sessions from expected source IPs
- Automated configuration management tools accessing admin API endpoints
- Security assessment tools during authorized penetration tests
- Internal monitoring systems polling FreePBX health endpoints
Other platforms for CVE-2019-19006
Testing Methodology
Validate this detection against 4 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 1Unauthenticated FreePBX Admin Panel Access Probe
Expected signal: Web server access log entry showing GET /admin/config.php returning HTTP 200 with no prior authenticated session POST to login endpoint. No Set-Cookie with valid session token in prior requests.
- Test 2FreePBX Admin AJAX Endpoint Enumeration Without Auth
Expected signal: Multiple HTTP GET requests to /admin/ajax.php with varying query parameters from the same source IP within a short time window. Response codes of 200 indicate the endpoints are reachable without authentication.
- Test 3FreePBX Unauthorized Admin Account Creation Simulation
Expected signal: HTTP POST to /admin/config.php with user creation parameters visible in request body. If exploitation succeeds, FreePBX audit logs should show a new user account creation without a corresponding prior admin login. MySQL binary logs capture INSERT into user tables.
- Test 4Network Scan for Exposed FreePBX Admin Interfaces
Expected signal: Network scan traffic visible in IDS/IPS logs and firewall flow logs. HTTP probes to /admin/ path generate web server access log entries. Port scan signatures may trigger on receiving host if endpoint detection is installed.
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