Detect Versa Concerto Improper Authentication (CVE-2025-34026) in Microsoft Sentinel
Detects exploitation attempts targeting CVE-2025-34026, an improper authentication vulnerability (CWE-288) in Versa Concerto SD-WAN orchestration platform. This vulnerability allows attackers to bypass authentication controls, potentially enabling unauthorized access to the Concerto management interface. Listed as a CISA KEV, indicating active exploitation in the wild.
MITRE ATT&CK
KQL Detection Query
let VersaConcertoHosts = dynamic(["concerto", "versa", "sd-wan"]);
let SuspiciousUAPaths = dynamic(["/api/", "/auth/", "/login", "/admin", "/management"]);
union DeviceNetworkEvents, CommonSecurityLog, W3CIISLog
| where TimeGenerated > ago(24h)
| where (
(cs_UriStem has_any (SuspiciousUAPaths) and (sc_status in (200, 302) or sc_status between (400 .. 403)))
or (RequestURL has_any (SuspiciousUAPaths))
)
| where (
Computer has_any (VersaConcertoHosts)
or DestinationHostName has_any (VersaConcertoHosts)
or DeviceName has_any (VersaConcertoHosts)
)
| extend AuthBypass = case(
cs_status == 200 and cs_username == "-" and cs_UriStem has_any ("/api/", "/admin/"), "Unauthenticated access to protected endpoint",
RequestMethod == "GET" and RequestURL contains "/auth" and EventOutcome == "Success", "Auth bypass via GET",
"Normal"
)
| where AuthBypass != "Normal"
| project TimeGenerated, Computer, SourceIP, DestinationIP, RequestURL, cs_UriStem, sc_status, cs_username, AuthBypass, RequestMethod
| order by TimeGenerated descDetects unauthenticated or authentication-bypassed requests to Versa Concerto management endpoints. Flags successful responses to protected API/admin paths from unauthenticated sessions, consistent with CVE-2025-34026 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate administrative access to Concerto API from known management IPs
- Health check probes or monitoring systems accessing status endpoints without authentication
- Automated provisioning scripts using service accounts that may not log standard auth headers
- Pentest or vulnerability scanning activity against the Concerto platform
Other platforms for CVE-2025-34026
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 GET to Versa Concerto API Endpoint
Expected signal: HTTP access log on Concerto server showing GET /api/v1/system/info with source IP of test host, status 200, and empty/anonymous username field. Network flow showing connection to port 443.
- Test 2Authentication Bypass Probe via Malformed Auth Header
Expected signal: Series of HTTP requests to multiple protected paths logged on Concerto host. Network proxy logs showing path enumeration pattern from single source IP within short time window.
- Test 3Post-Authentication-Bypass Configuration Read
Expected signal: HTTP GET to /api/v1/vnf/inventory logged with 200 response and response body size. DLP or data exfiltration alerts if JSON response contains sensitive topology data. Network flow showing data transfer volume.
- Test 4Concerto Admin User Creation via Unauthenticated API
Expected signal: HTTP POST to /api/v1/users logged. Concerto audit log entry for user creation event. If successful, new user visible in Concerto user management interface.
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