Account takeover via prototype vulnerability

Vulnerability

Overview

NodeBB, an open-source Node.js forum software, is vulnerable to a prototype pollution vulnerability due to the use of a plain object with a prototype in its socket.io message handling [1]. This flaw allows an attacker to craft a specially payload that, when processed by the socket.io onMessage handler, can modify the Object prototype and inject malicious properties [3].

Exploitation

Path

The vulnerability is triggered by sending a crafted socket.io message to the server. No authentication is required to exploit the bug; an unauthenticated remote attacker can send the malicious payload because socket.io events are processed before any authentication checks [2]. The attack surface is the real-time messaging feature, which uses socket.io for instant interactions [2].

Impact

Successful exploitation enables an attacker to impersonate other users and completely takeover their accounts [1]. By manipulating the prototype, the attacker can override user identity properties, gaining full access to the victim's account, including private messages, personal settings, and any administrative privileges the victim may have.

Mitigation

The vulnerability has been patched in NodeBB version 2.6.1 [4]. Users should upgrade immediately. Those unable to upgrade immediately can cherry-pick commit 48d143921753914da45926cca6370a92ed0c46b8 from the NodeBB repository to apply the fix [1].