Detect Kentico Xperience CMS Authentication Bypass (CVE-2025-2747) in Google Chronicle
Detects exploitation of CVE-2025-2747, an authentication bypass vulnerability (CWE-288) in Kentico Xperience CMS. Attackers can access protected administrative or content management endpoints via alternate paths or channels without valid credentials, enabling unauthorized access to sensitive CMS functionality. This vulnerability is actively exploited in the wild and listed in CISA KEV.
MITRE ATT&CK
YARA-L Detection Query
rule kentico_xperience_auth_bypass_cve_2025_2747 {
meta:
author = "df00tech"
description = "Detects unauthenticated access to Kentico Xperience CMS administrative paths - CVE-2025-2747"
severity = "CRITICAL"
yara_version = "YL2.0"
rule_version = "1.0"
events:
$req.metadata.event_type = "NETWORK_HTTP"
$req.network.http.response_code in (200, 201, 302)
(
re.regex($req.target.url, `(?i)/CMSPages/`) or
re.regex($req.target.url, `(?i)/CMSModules/`) or
re.regex($req.target.url, `(?i)/Admin/`) or
re.regex($req.target.url, `(?i)/KenticoCMS/`) or
re.regex($req.target.url, `(?i)/CMS/SiteManager`) or
re.regex($req.target.url, `(?i)/CMSDesk`)
)
not re.regex($req.principal.user.userid, `^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`)
condition:
$req
}Chronicle YARA-L rule detecting HTTP requests to Kentico Xperience CMS administrative paths that succeed without an authenticated user identity, indicative of CVE-2025-2747 exploitation.
Data Sources
Required Tables
False Positives & Tuning
- Kentico CMS public pages served under paths that overlap with admin path patterns
- Service accounts whose UPN format does not match the email regex pattern
- Anonymous public content served via CMS module infrastructure
- Load balancer health check probes targeting CMS endpoints
Other platforms for CVE-2025-2747
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.
- Test 1Kentico CMS Unauthenticated Admin Path Access Simulation
Expected signal: IIS access logs will record HTTP GET requests to each tested path with the source IP of the test host; requests will appear with no authenticated username (cs_username = '-').
- Test 2Alternate Channel Authentication Bypass via Parameter Manipulation
Expected signal: Web server logs capture each variant request with full URI including query string; WAF logs may flag path traversal patterns in the query string.
- Test 3Post-Bypass Webshell Upload Simulation via CMS File Manager
Expected signal: Windows Security Event Log will show file creation event (Event ID 4663) for test_detection.aspx under the CMS web root; Sysmon Event ID 11 (FileCreate) will capture the new .aspx file creation with the IIS worker process (w3wp.exe) as the creator.
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