Ret2vDSO

👉 Overview

👀 What ?

Ret2vDSO (Return to vDSO) is a form of cyber attack in which an attacker exploits a vulnerability in the vDSO (virtual Dynamic Shared Object) of a Linux system to execute malicious code.

🧐 Why ?

Understanding Ret2vDSO is crucial due to its potential for severe damage. This technique can be used to bypass security measures and gain unauthorized access to a system. It's particularly concerning because vDSO is commonly used in Linux systems to make system calls more efficient. Thus, a vulnerability in vDSO can affect a large number of systems.

⛏️ How ?

To use Ret2vDSO, an attacker first needs to find a vulnerability in the vDSO. This could be a buffer overflow or other type of flaw that allows arbitrary code execution. Once the vulnerability is found, the attacker can craft a payload that, when executed, returns control to the vDSO and then to the malicious code. This can be achieved through techniques such as ROP (Return Oriented Programming).

⏳ When ?

The concept of Ret2vDSO started gaining attention in the cybersecurity community around the mid-2010s, as researchers began to explore more sophisticated ways of exploiting Linux systems.

⚙️ Technical Explanations

The vDSO is a shared library that Linux systems use to speed up certain system calls. Instead of switching from user mode to kernel mode, which can be time-consuming, vDSO allows these system calls to be made in user mode. This efficiency, however, opens up a potential attack vector. If an attacker can find a vulnerability in the vDSO, they can exploit it to return control to the vDSO and then to their own malicious code. This is done using techniques such as ROP, which involves chaining together bits of code (gadgets) that end in a 'return' instruction. The attacker crafts a payload that, when executed, transfers control to these gadgets and ultimately to the malicious code.