Courses
1. Introduction to Blockchain and Solana
2. Setting Up Your Development Environment
3. Solana Architecture and Key Concepts
4. Creating and Managing Wallets
5. Understanding Solana Programs
6. Building Your First Solana Program
7. Deploying Programs on the Solana Network
8. Interacting with Solana Programs
9. Using Solana CLI and SDKs
10. Developing Decentralized Applications (DApps)
11. Smart Contract Security Best Practices
12. Testing and Debugging Solana Programs
13. Optimizing Performance on Solana
14. Exploring Solana Ecosystem Tools
1. Introduction to Blockchain and Ethereum
2. Setting Up Your Development Environment
3. Ethereum Architecture and Key Concepts
4. Creating and Managing Wallets
5. Understanding Smart Contracts
6. Building Your First Smart Contract
7. Deploying Smart Contracts on the Ethereum Network
8. Interacting with Smart Contracts
9. Using Ethereum CLI and SDKs
10. Developing Decentralized Applications (DApps)
11. Smart Contract Security Best Practices
12. Testing and Debugging Smart Contracts
13. Optimizing Performance on Ethereum
14. Exploring Ethereum Ecosystem Tools
1. Introduction to Blockchain and Polygon
2. Setting Up Your Development Environment
3. Polygon Architecture and Key Concepts
4. Creating and Managing Wallets
5. Understanding Smart Contracts on Polygon
6. Building Your First Smart Contract on Polygon
7. Deploying Smart Contracts on the Polygon Network
8. Interacting with Smart Contracts on Polygon
9. Using Polygon CLI and SDKs
10. Developing Decentralized Applications (DApps) on Polygon
11. Smart Contract Security Best Practices for Polygon
12. Testing and Debugging Smart Contracts on Polygon
13. Optimizing Performance on Polygon
14. Exploring Polygon Ecosystem Tools
1. Introduction to Cybersecurity
2. Report Writing for Penetration Testers
3. Information Gathering
4. Vulnerability Scanning
5. Introduction to Web Applications
6. Common Web Application Attacks
7. SQL Injection Attacks
8. Client-Side Attacks
9. Locating Public Exploits
10. Fixing Exploits
11. Antivirus Evasion
12. Password Attacks
13. Windows Privilege Escalation
14. Linux Privilege Escalation
15. Advanced Tunneling
16. The Metasploit Framework
17. Active Directory: Introduction and Enumeration
18. Attacking Active Directory Authentication
19. Lateral Movement in Active Directory
UDF Reverse Shells
OSWE · Chapter 17
UDF Reverse Shells
A UDF reverse shell is the practical exploitation outcome of the PostgreSQL User-Defined Function technique covered earlier: once an attacker can register a native C UDF, they can implement a function that spawns a shell connected back to an attacker-controlled listener.
Key concepts
- This requires the same precondition as any C UDF abuse: sufficient privilege (superuser) to run `CREATE FUNCTION ... LANGUAGE C`, and the ability to place a compiled shared object where PostgreSQL can load it.
- The compiled function typically calls a system-level exec/fork routine from within the C UDF body — this is why C-language UDFs are so much more dangerous than UDFs in a sandboxed procedural language (PL/pgSQL).
- This is a well-documented post-exploitation technique in tools like Metasploit's PostgreSQL modules, used once database-level admin access is already achieved — not an initial-access technique.
- Defense: never grant `CREATEROLE`/superuser to application accounts, and monitor for unexpected `CREATE FUNCTION ... LANGUAGE C` statements in database audit logs.
Try it yourself
Read the Metasploit PostgreSQL pentesting guide and identify which specific privilege level the documented modules require before a UDF-based code execution technique becomes possible.