Detect Cisco Catalyst SD-WAN Manager Improper Output Encoding Exploitation in CrowdStrike LogScale
Detects exploitation attempts targeting CVE-2026-20245, an improper encoding or escaping of output vulnerability (CWE-116) in Cisco Catalyst SD-WAN Manager. This vulnerability is actively exploited in the wild (CISA KEV) and may allow attackers to perform privilege escalation or inject malicious content through improperly encoded output. Detection focuses on anomalous authentication patterns, unexpected privilege changes, API abuse, and suspicious management plane activity against SD-WAN Manager instances.
MITRE ATT&CK
LogScale Detection Query
#event_simpleName in ("NetworkConnectIP4", "NetworkReceiveAcceptIP4", "ProcessRollup2", "SyntheticProcessRollup2")
| HostName = /vmanage|sdwan.?manager|sdwanmgr/i
OR ImageFileName = /vmanage|sdwan/i
| eval suspicious = case(
CommandLine = /privilege.escal/i, "PrivilegeEscalation",
CommandLine = /unauthorized.*admin/i, "UnauthorizedAdmin",
RemotePort in (443, 8443) AND ConnectionDirection = "1", "InboundMgmtConnection",
ImageFileName = /sh|bash|python/ AND ParentBaseFileName = /vmanage|java/, "ShellSpawnedFromSDWAN",
true(), "Other"
)
| suspicious != "Other"
| groupby([HostName, suspicious, ImageFileName, CommandLine], function=count(1, as=event_count))
| sort(event_count, order=desc)
| limit 200CrowdStrike Falcon query hunting for anomalous process and network activity on Cisco SD-WAN Manager hosts — including privilege escalation command patterns, inbound management connections, and unexpected shell processes spawned from SD-WAN Manager JVM.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate SD-WAN Manager maintenance scripts executing shell commands during upgrades
- Authorized administrative SSH or API sessions from known management IPs
- SD-WAN Manager health monitoring daemons establishing outbound connections to Cisco cloud telemetry
- CrowdStrike sensor installed on SD-WAN Manager VM generating false process attribution
Other platforms for CVE-2026-20245
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 1SD-WAN Manager REST API Endpoint Enumeration and Auth Probe
Expected signal: Web server access logs and SD-WAN Manager audit logs should record multiple 401/403 responses to /dataservice/ endpoints from the probe source IP within a short time window
- Test 2Simulate Output Encoding Bypass via Crafted API Payload
Expected signal: SD-WAN Manager application logs should record the API request with the encoded payload; web access logs capture the POST to /dataservice/users with unexpected encoded characters in request body
- Test 3Post-Exploitation Privilege Escalation Simulation via vManage Admin API
Expected signal: SD-WAN Manager audit logs should record the group membership change attempt; if successful, an entry will appear under Administration > Audit Log showing the privilege modification with source IP and timestamp
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