Detect Sangoma FreePBX OS Command Injection (CVE-2025-64328) in Google Chronicle
Detects exploitation of an OS command injection vulnerability in Sangoma FreePBX. An authenticated or unauthenticated attacker may inject arbitrary OS commands through vulnerable FreePBX web interfaces or API endpoints, leading to remote code execution on the underlying Linux host. This vulnerability is tracked as CVE-2025-64328 and is listed in CISA's Known Exploited Vulnerabilities catalog.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
YARA-L Detection Query
rule freepbx_os_command_injection_cve_2025_64328 {
meta:
author = "df00tech"
description = "Detects OS command injection exploitation in Sangoma FreePBX (CVE-2025-64328)"
severity = "CRITICAL"
priority = "HIGH"
reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-64328"
events:
$e.metadata.event_type = "PROCESS_LAUNCH"
$e.principal.process.parent_process.file.full_path = /asterisk|freepbx|amportal|httpd|apache2|php|nginx/
(
$e.principal.process.file.full_path = /\/(sh|bash|dash|ksh|python3?|perl|nc|ncat|curl|wget|socat|base64|id|whoami)$/
or $e.principal.process.command_line = /bash -i|dev\/tcp|python -c|perl -e|nc -e|mkfifo|base64 -d|socat/
)
condition:
$e
}Chronicle YARA-L rule detecting processes spawned from FreePBX/Asterisk that match command injection shellcode patterns.
Data Sources
Required Tables
False Positives & Tuning
- AGI scripts in Asterisk dial plans that legitimately call bash utilities
- FreePBX administrative automation scripts run as the asterisk service user
- Security tooling processes that enumerate system state under web server contexts
Other platforms for CVE-2025-64328
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 1FreePBX OS Command Injection via Admin Web Interface Parameter
Expected signal: Linux audit log entry for execve of 'id' with ppid mapping to httpd/apache2; DeviceProcessEvents showing id or sh spawned from apache2 parent process
- Test 2Reverse Shell Establishment via FreePBX Command Injection
Expected signal: DeviceNetworkEvents showing outbound TCP connection from FreePBX host to ATTACKER_IP:4444 initiated by bash process with asterisk user context; auditd execve of bash with -i flag
- Test 3Post-Exploitation Persistence via Cron Job Implant
Expected signal: File creation or modification event for /var/spool/cron/asterisk; auditd SYSCALL write to cron spool directory by asterisk UID
- Test 4Web Shell Deployment Following FreePBX Command Injection
Expected signal: File creation event for shell.php in FreePBX web root directory with www-data initiating process; subsequent HTTP GET request to shell.php with cmd parameter; DeviceProcessEvents showing id spawned from httpd/apache2
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