Detect CVE-2026-20045: Cisco Unified Communications Manager Code Injection in Elastic Security
Detects exploitation attempts targeting CVE-2026-20045, a code injection vulnerability (CWE-94) in Cisco Unified Communications Manager. This KEV-listed vulnerability allows remote attackers to inject and execute arbitrary code. Detection focuses on anomalous process execution, unexpected web shell activity, and suspicious outbound connections originating from CUCM processes.
MITRE ATT&CK
Elastic Detection Query
sequence by host.name with maxspan=5m
[process where event.type == "start"
and process.parent.name in ("java", "catalina.sh", "tomcat")
and process.name in ("sh", "bash", "python", "python3", "perl", "wget", "curl", "nc")]
[any where
(event.category == "network" and network.direction == "egress" and
not destination.ip in ("127.0.0.1", "::1") and destination.port in (80, 443, 4444, 8080, 8443, 9001))
or
(event.category == "file" and file.path like~ "/opt/cisco/*" and event.action in ("creation", "overwrite"))]EQL sequence rule detecting the pattern of Java/Tomcat process spawning a shell followed by suspicious outbound network activity or file creation on Cisco UCM hosts, indicative of post-exploitation after CVE-2026-20045.
Data Sources
Required Tables
False Positives & Tuning
- CUCM backup scripts that use shell and make outbound connections to backup servers
- Monitoring agents spawned under the Tomcat service account
- Legitimate software updates that write to /opt/cisco paths
Other platforms for CVE-2026-20045
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 1CVE-2026-20045 Code Injection via AXL SOAP Endpoint
Expected signal: Tomcat access log entry showing POST to /axl/ with HTTP 200 or 500; if successful, process audit log showing command substitution execution under Tomcat user; /tmp/rce_test.txt created on CUCM host
- Test 2Simulate Java Spawning Reverse Shell on CUCM OS
Expected signal: ProcessRollup2 event (CrowdStrike) or DeviceProcessEvents (MDE) showing bash or java process with parent java; network connection to ATTACKER_IP:4444 if reverse shell variant used
- Test 3Web Shell Deployment Simulation on CUCM Tomcat
Expected signal: File creation event for .jsp file in /opt/cisco/platform/ui/; if Tomcat is running, subsequent HTTP GET requests to the new JSP path; audit log showing file write under test user account
- Test 4AXL Credential Brute-Force Reconnaissance
Expected signal: Multiple HTTP 401/403 responses from CUCM to the source IP in rapid succession; authentication failure events in CUCM security logs; CommonSecurityLog or Syslog entries showing repeated failed logins
Unlock Pro Content
Get the full detection package for CVE-2026-20045 including response playbook, investigation guide, and atomic red team tests.