Detect Versa Concerto Improper Authentication (CVE-2025-34026) in CrowdStrike LogScale
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
LogScale Detection Query
#event_simpleName=NetworkConnectIP4
| ExternalNetworkAccess=true OR RemotePort in (80, 443, 8080, 8443)
| TargetAddressIP4 = /(?i)(concerto|versa)/
OR HttpUrl = /(?i)\/(api|auth|admin|management|login)/
| HttpStatusCode = 200
| (HttpUsername = null OR HttpUsername = "-" OR HttpUsername = "anonymous")
| groupby([RemoteAddressIP4, TargetAddressIP4, HttpUrl, HttpStatusCode, HttpMethod, HttpUsername], function=count())
| rename count() as attempt_count
| sort -attempt_count
| limit 100CrowdStrike CQL query identifying successful unauthenticated HTTP connections to Versa Concerto management endpoints from external IPs. Aggregates by source, target, and URL path to surface repeated exploitation patterns.
Data Sources
Required Tables
False Positives & Tuning
- Automated scripts polling Concerto API endpoints using bearer tokens not captured in HttpUsername
- DevOps pipelines interacting with Concerto management API without user-level auth context
- External monitoring services checking Concerto availability
- Authorized red team exercises targeting network infrastructure
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.
Unlock Pro Content
Get the full detection package for CVE-2025-34026 including response playbook, investigation guide, and atomic red team tests.