Timestomping Vulnerability of Age-Sensitive Gossip Networks

TL;DR

This paper investigates how an adversary manipulating timestamps in gossip networks can significantly degrade information freshness, with effects varying based on network topology, highlighting vulnerabilities in fully connected networks and resilience in ring structures.

Contribution

It introduces a detailed analysis of timestamp-based attacks on age-sensitive gossip networks, revealing how topology influences vulnerability and demonstrating the potential for severe age degradation.

Findings

In fully connected networks, a single infected node can increase age from O(log n) to O(n).

In ring networks, the adversarial impact is limited, maintaining an age of O(√n) for most nodes.

Optimal adversarial strategy involves resetting timestamps to outdated values to prevent fresh information flow.

Abstract

We consider gossip networks consisting of a source that maintains the current version of a file, $n$ nodes that use asynchronous gossip mechanisms to disseminate fresh information in the network, and an oblivious adversary who infects the packets at a target node through data timestamp manipulation, with the intent to replace circulation of fresh packets with outdated packets in the network. We demonstrate how network topology capacitates an adversary to influence age scaling in a network. We show that in a fully connected network, a single infected node increases the expected age from $O(\log n)$ to $O(n)$. Further, we show that the optimal behavior for an adversary is to reset the timestamps of all outgoing packets to the current time and of all incoming packets to an outdated time for the infected node; thereby preventing any fresh information to go into the infected node, and facilitating acceptance of stale information out of the infected node into other network nodes. Lastly for fully connected network, we show that if an infected node contacts only a single node instead of all nodes of the network, the system age can still be degraded to $O(n)$. These show that fully connected nature of a network can be both a benefit and a detriment for information freshness; full connectivity, while enabling fast dissemination of information, also enables fast dissipation of adversarial inputs. We then analyze the unidirectional ring network, the other end of the network connectivity spectrum, where we show that the adversarial effect on age scaling of a node is limited by its distance from the adversary, and the age scaling for a large fraction of the network continues to be $O(\sqrt{n})$, unchanged from the case with no adversary. We finally support our findings with simulations.