CVE-2025-49844 PoC — Redis Lua Use-After-Free may lead to remote code execution

Source

https://github.com/lastvocher/redis-CVE-2025-49844

Associated Vulnerability

Title:Redis Lua Use-After-Free may lead to remote code execution (CVE-2025-49844)
Description:Redis is an open source, in-memory database that persists on disk. Versions 8.2.1 and below allow an authenticated user to use a specially crafted Lua script to manipulate the garbage collector, trigger a use-after-free and potentially lead to remote code execution. The problem exists in all versions of Redis with Lua scripting. This issue is fixed in version 8.2.2. To workaround this issue without patching the redis-server executable is to prevent users from executing Lua scripts. This can be done using ACL to restrict EVAL and EVALSHA commands.

Readme

# CVE-2025-49844 (RediShell) - Lab Environment

A practical lab environment for testing and understanding the critical **CVE-2025-49844 (RediShell)** vulnerability in Redis.

## ⚠️ WARNING

**This is for educational purposes only!**
- Only use on systems you own or have explicit permission to test
- Never expose to the internet
- Never use in production environments

## About the Vulnerability

- **CVE ID**: CVE-2025-49844
- **Name**: RediShell
- **CVSS Score**: 10.0 (Critical)
- **Type**: Use-After-Free (UAF) in Lua Interpreter
- **Impact**: Remote Code Execution (RCE)
- **Discovered by**: Wiz Research Team

### Vulnerable Versions

All Redis versions before:
- Redis 8.2.2
- Redis 8.0.4
- Redis 7.4.6
- Redis 7.2.11

This lab uses **Redis 7.2.0** (vulnerable version).

## Quick Start

### Prerequisites

```bash
# Install Docker and Docker Compose
sudo apt-get update
sudo apt-get install docker.io docker-compose

# Install Python dependencies
pip install redis colorama
```

### Setup and Run

```bash
# 1. Start vulnerable Redis instance
docker-compose up -d

# 2. Wait a few seconds for Redis to start
sleep 5

# 3. Verify Redis is running
docker-compose ps

# 4. Run the exploit
python3 exploit_poc.py -H localhost -p 6380 -m all
```

## Usage

### Basic Commands

```bash
# Check vulnerability only
python3 exploit_poc.py -H localhost -p 6380 -m check

# Run basic UAF test
python3 exploit_poc.py -H localhost -p 6380 -m basic

# Test sandbox escape
python3 exploit_poc.py -H localhost -p 6380 -m sandbox

# Test advanced memory corruption
python3 exploit_poc.py -H localhost -p 6380 -m advanced

# Run all tests
python3 exploit_poc.py -H localhost -p 6380 -m all

# With authentication
python3 exploit_poc.py -H localhost -p 6380 -a "password" -m all
```

### Docker Management

```bash
# View logs
docker-compose logs -f

# Connect to Redis CLI
docker-compose exec redis-vulnerable redis-cli

# Stop the lab
docker-compose down

# Remove everything (including volumes)
docker-compose down -v
```

## Expected Output

### Successful Test (Vulnerable Version)

```
╔═══════════════════════════════════════════════════════════╗
║          CVE-2025-49844 (RediShell) PoC                  ║
║          Use-After-Free in Redis Lua Interpreter         ║
║          CVSS Score: 10.0 (CRITICAL)                     ║
╚═══════════════════════════════════════════════════════════╝

[*] Testing connection to localhost:6380...
[+] Connected successfully!
[i] Redis Version: 7.2.0
[*] Checking if Lua scripting is enabled...
[+] Lua scripting is enabled!

[*] Checking vulnerability status...
[i] Detected Redis version: 7.2.0
[!] VULNERABLE: This version is affected by CVE-2025-49844
[!] Update to the latest patched version immediately!

[*] Attempting basic UAF trigger...
[+] Lua script executed: UAF pattern executed
[!] UAF pattern triggered (simplified demo)

[*] Testing Lua sandbox boundaries...
[*] Testing os.execute...
[+] Protected: os.execute blocked
[*] Testing io.popen...
[+] Protected: io.popen blocked
[*] Testing loadfile...
[+] Protected: loadfile blocked
[*] Testing package.loadlib...
[+] Protected: package.loadlib blocked

[*] Attempting memory corruption pattern...
[+] Memory corruption pattern executed: Memory corruption pattern completed
[!] In vulnerable versions, this could lead to RCE!

============================================================
[*] PoC execution completed
============================================================
```

## How the Vulnerability Works

### Attack Flow

1. **Connect to Redis** (authenticated or unauthenticated)
2. **Send malicious Lua script** via EVAL command
3. **Trigger Use-After-Free** through garbage collection
4. **Escape Lua sandbox** to access restricted functions
5. **Execute arbitrary native code** outside the sandbox
6. **Gain full host access** for data exfiltration, malware installation, etc.

### Technical Details

The vulnerability exploits a 13-year-old Use-After-Free bug in Redis's Lua interpreter:

- **Memory Corruption**: Improper memory management during garbage collection
- **Sandbox Escape**: Bypass Lua sandbox restrictions
- **Code Execution**: Execute arbitrary system commands
- **Full Compromise**: Complete access to the host system

## Security Recommendations

### 1. Update Immediately

```bash
# Pull latest patched version
docker pull redis:8.2.2
# or
docker pull redis:7.4.6
```

### 2. Secure Configuration

```conf
# /etc/redis/redis.conf

# Enable authentication
requirepass your_strong_password_here

# Restrict network access
bind 127.0.0.1 ::1
protected-mode yes

# Disable dangerous commands
rename-command FLUSHDB ""
rename-command FLUSHALL ""
rename-command CONFIG ""
rename-command EVAL ""
rename-command EVALSHA ""

# Enable logging
loglevel notice
logfile /var/log/redis/redis-server.log
```

### 3. Use Redis ACL

```bash
# Disable Lua scripting for specific users
redis-cli ACL SETUSER myuser -@scripting

# Create limited user
redis-cli ACL SETUSER limited on >password ~* +@read +@write -@scripting
```

### 4. Network Security

```bash
# Use firewall rules
sudo ufw allow from 192.168.1.0/24 to any port 6379
sudo ufw deny 6379

# Or use iptables
sudo iptables -A INPUT -p tcp --dport 6379 -s 192.168.1.0/24 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 6379 -j DROP
```

## Troubleshooting

### Port Already in Use

```bash
# Check what's using the port
sudo lsof -i :6380

# Or change port in docker-compose.yml
# ports:
#   - "6381:6379"
```

### Python Module Not Found

```bash
# Install required packages
pip install redis colorama

# Or use virtual environment
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
```

### Docker Permission Denied

```bash
# Add user to docker group
sudo usermod -aG docker $USER

# Then logout and login again
```

### Redis Not Starting

```bash
# Check logs
docker-compose logs

# Restart container
docker-compose restart

# Rebuild image
docker-compose up -d --build
```

## Project Structure

```
redis_exploit/
├── Dockerfile              # Redis 7.2.0 vulnerable instance
├── docker-compose.yml      # Docker Compose configuration
├── exploit_poc.py          # Main exploit script
├── requirements.txt        # Python dependencies
├── .gitignore             # Git ignore file
└── README.md              # This file
```

## References

- [Wiz Research Blog - RediShell](https://www.wiz.io/blog/wiz-research-redis-rce-cve-2025-49844)
- [BleepingComputer Article](https://www.bleepingcomputer.com/news/security/redis-warns-of-max-severity-flaw-impacting-thousands-of-instances/)
- [Redis Security Advisory](https://redis.io/blog/security-advisory-cve-2025-49844/)


## Disclaimer

This PoC is simplified and for educational purposes only. The actual CVE-2025-49844 exploit involves complex memory manipulation. Always patch your Redis instances to the latest version!

File Snapshot


 [4.0K]  /data/pocs/7761a34574cd62c92edbe3b1f39f784ecd8a8733
├── [ 286]  docker-compose.yml
├── [ 728]  Dockerfile
├── [ 10K]  exploit_poc.py
├── [7.0K]  README.md
└── [  29]  requirements.txt

1 directory, 5 files

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