The detection of automated accounts, also known as "social bots", has been an increasingly important concern for online social networks (OSNs). While several methods have been proposed for detecting social bots, significant research gaps remain. First, current models exhibit limitations in detecting sophisticated bots that aim to mimic genuine OSN users. Second, these methods often rely on simplistic profile features, which are susceptible to manipulation. In addition to their vulnerability to adversarial manipulations, these models lack generalizability, resulting in subpar performance when trained on one dataset and tested on another. To address these challenges, we propose a novel framework for social Bot detection with Self-Supervised Contrastive Learning (BotSSCL). Our framework leverages contrastive learning to distinguish between social bots and humans in the embedding space to improve linear separability. The high-level representations derived by BotSSCL enhance its resilience to variations in data distribution and ensure generalizability. We evaluate BotSSCL's robustness against adversarial attempts to manipulate bot accounts to evade detection. Experiments on two datasets featuring sophisticated bots demonstrate that BotSSCL outperforms other supervised, unsupervised, and self-supervised baseline methods. We achieve approx. 6% and approx. 8% higher (F1) performance than SOTA on both datasets. In addition, BotSSCL also achieves 67% F1 when trained on one dataset and tested with another, demonstrating its generalizability. Lastly, BotSSCL increases adversarial complexity and only allows 4% success to the adversary in evading detection.

我们提出了一种基于自监督对比学习的社交机器人检测框架（BotSSCL），通过利用对比学习在嵌入空间中区分社交机器人和人类，改善了线性可分性。BotSSCL的高级表示增强了对数据分布变化的鲁棒性并确保了泛化性能。实验证明，BotSSCL在两个数据集上的性能较其他监督、无监督和自监督基准方法都要高，并且在不同数据集间的测试也表现出较好的泛化性能。此外，BotSSCL还提高了对抗复杂性，使对手在逃避检测方面的成功率只有4%。

BotSSCL: 自监督对比学习中的社交机器人检测