Detect Fission Container Executor PodSpec Injection - Node Escape Attempt in IBM QRadar
Detects exploitation of CVE-2026-50563, a critical privilege escalation vulnerability in Fission serverless framework (<=1.23.0). The container executor allows unauthenticated or low-privileged users to inject arbitrary PodSpec fields into function pods, enabling container escape to the underlying Kubernetes node. Attackers can inject hostPID, hostNetwork, privileged containers, hostPath volume mounts, or custom service accounts to achieve full node compromise.
MITRE ATT&CK
QRadar Detection Query
SELECT
DATEFORMAT(starttime, 'YYYY-MM-dd HH:mm:ss') AS EventTime,
sourceip AS SourceIP,
username AS Username,
"devicepayload" AS RawPayload,
CATEGORYDESCRIPTION(category) AS EventCategory,
logsourcename(logsourceid) AS LogSource
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) ILIKE '%kubernetes%'
AND (
("devicepayload" ILIKE '%"namespace":"fission%'
AND "devicepayload" ILIKE '%"verb":"create"%'
AND "devicepayload" ILIKE '%"resource":"pods"%'
AND (
"devicepayload" ILIKE '%"hostPID":true%'
OR "devicepayload" ILIKE '%"hostNetwork":true%'
OR "devicepayload" ILIKE '%"privileged":true%'
OR "devicepayload" ILIKE '%"hostPath"%'
OR "devicepayload" ILIKE '%"hostIPC":true%'
)
)
OR
("devicepayload" ILIKE '%fission%'
AND (
"devicepayload" ILIKE '%nsenter%'
OR "devicepayload" ILIKE '%/proc/1/root%'
OR "devicepayload" ILIKE '%/host/%'
)
)
)
AND QIDNAME(qid) NOT ILIKE '%test%'
LAST 24 HOURSAQL query detecting Fission namespace pod creation with privileged PodSpec fields and container escape indicators from Kubernetes log sources.
Data Sources
Required Tables
False Positives & Tuning
- Cluster upgrade operations that temporarily create privileged system pods in Fission-adjacent namespaces
- Legitimate node maintenance tasks using nsenter for container inspection by authorized operations staff
- CI/CD pipeline integration tests that spin up Fission environments with elevated privileges in dedicated test clusters
Other platforms for CVE-2026-50563
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 1Fission PodSpec Injection - hostPID Escape
Expected signal: Kubernetes audit log entry with verb=create, objectRef.resource=pods, objectRef.namespace=fission-function, requestObject.spec.hostPID=true. Container process list will show host-level PIDs including kubelet, containerd, and other node processes.
- Test 2Fission PodSpec Injection - Privileged Container with hostPath Root Mount
Expected signal: Kubernetes audit log with requestObject.spec.containers[0].securityContext.privileged=true and requestObject.spec.volumes containing hostPath.path=/. Container runtime logs showing privileged container start. Node-level filesystem access to /etc/passwd and hostname file.
- Test 3Fission Container Escape via nsenter After PodSpec Injection
Expected signal: Process telemetry on Kubernetes node showing nsenter executed with --target 1 argument. Host PID 1 (init/systemd) namespace join event visible in node audit logs. Container log output matching host OS details rather than Alpine container OS.
References (6)
- https://github.com/fission/fission/security/advisories/GHSA-v455-mv2v-5g92
- https://nvd.nist.gov/vuln/detail/CVE-2026-50563
- https://github.com/fission/fission/pull/3391
- https://github.com/fission/fission/commit/e484df8460bb4e8026e24210120602aa7f181f64
- https://github.com/fission/fission/releases/tag/v1.24.0
- https://github.com/advisories/GHSA-v455-mv2v-5g92
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