Identifiable Header Values In Fuchsia Leading To Tracking of The User

Vulnerability

Fuchsia's algorithms for generating network protocol header fields, including TCP Initial Sequence Numbers (ISN), TCP timestamps, TCP and UDP source ports, and IPv4/IPv6 fragment IDs, are predictable under certain circumstances. This allows an attacker to guess these values without direct access to the system. The vulnerability affects Fuchsia versions prior to the fixes introduced in commits [1] and [2].

Exploitation

An attacker with network access to a Fuchsia device can guess the predictable header fields by observing network traffic or performing statistical analysis. No authentication or user interaction is required; the attacker can remotely infer values such as TCP ISN and source ports, enabling further attacks.

Impact

Successful guessing of these fields can lead to a range of attacks, including TCP connection hijacking, spoofing of network packets, and denial of service by crafting packets that terminate or interfere with existing connections. The attacker may gain the ability to impersonate trusted hosts or disrupt communications.

Mitigation

Fuchsia has addressed these vulnerabilities in commits [1] and [2]. Users should update to the latest Fuchsia build containing these fixes. No workarounds are available for unpatched versions.