Detect Trend Micro Apex One Directory Traversal Exploitation (CVE-2026-34926) in Microsoft Sentinel
Detects exploitation attempts targeting CVE-2026-34926, a directory traversal vulnerability (CWE-23) in Trend Micro Apex One (On-Premise). This KEV-listed vulnerability allows unauthenticated or low-privileged attackers to traverse directory boundaries via crafted HTTP requests to the Apex One management server, potentially enabling arbitrary file read or write operations. Active exploitation has been observed in the wild.
MITRE ATT&CK
KQL Detection Query
union DeviceNetworkEvents, W3CIISlogs, AzureDiagnostics
| where TimeGenerated > ago(7d)
| where (
(RequestUri has "..%2F" or RequestUri has "..%5C" or RequestUri has "%2e%2e%2f" or RequestUri has "%2e%2e/" or RequestUri has "....//" or RequestUri has "..%252F")
and (RequestUri contains "/officescan" or RequestUri contains "/apex_one" or RequestUri contains "/OfficeScan" or RequestUri contains "/widget" or RequestUri contains "/ServerMigration")
)
| extend TraversalDepth = countof(RequestUri, "..")
| where TraversalDepth >= 2
| project TimeGenerated, RemoteIP, RequestUri, HttpMethod, HttpStatusCode, UserAgent, TraversalDepth
| order by TimeGenerated descDetects HTTP requests to Trend Micro Apex One endpoints containing directory traversal sequences. Targets known Apex One URL paths with double-encoded and plain traversal patterns.
Data Sources
Required Tables
False Positives & Tuning
- Security scanning tools (Qualys, Nessus, Tenable) performing authenticated vulnerability assessments against Apex One
- Legitimate URL encoding in application traffic that coincidentally includes dot-dot sequences
- Penetration testing engagements with prior authorization targeting the Apex One management console
Other platforms for CVE-2026-34926
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 1Basic Directory Traversal Probe Against Apex One CGI Endpoint
Expected signal: IIS access log entry with traversal sequence in cs-uri-query field, HTTP response code indicating success (200) or path not found (404). Network connection event from test host to Apex One server on port 4343.
- Test 2Double-Encoded Traversal Bypass Attempt
Expected signal: Multiple IIS access log entries with different traversal encoding variants. Possible WAF alert if WAF is deployed. Network events showing rapid sequential HTTP requests to Apex One from the same source IP.
- Test 3Windows Apex One Traversal Simulation via PowerShell
Expected signal: Windows Security Event Log entry for PowerShell execution (Event ID 4688 or Sysmon Event ID 1). Network connection events from the Windows test host to Apex One server port 4343. IIS access log entries on Apex One server matching traversal patterns.
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