  Advanced persistent threats (APTs) have novel features such as multi-stage
penetration, highly-tailored intention, and evasive tactics. APTs defense
requires fusing multi-dimensional Cyber threat intelligence data to identify
attack intentions and conducts efficient knowledge discovery strategies by
data-driven machine learning to recognize entity relationships. However,
data-driven machine learning lacks generalization ability on fresh or unknown
samples, reducing the accuracy and practicality of the defense model. Besides,
the private deployment of these APT defense models on heterogeneous
environments and various network devices requires significant investment in
context awareness (such as known attack entities, continuous network states,
and current security strategies). In this paper, we propose a few-shot
multi-domain knowledge rearming (FMKR) scheme for context-aware defense against
APTs. By completing multiple small tasks that are generated from different
network domains with meta-learning, the FMKR firstly trains a model with good
discrimination and generalization ability for fresh and unknown APT attacks. In
each FMKR task, both threat intelligence and local entities are fused into the
support/query sets in meta-learning to identify possible attack stages.
Secondly, to rearm current security strategies, an finetuning-based deployment
mechanism is proposed to transfer learned knowledge into the student model,
while minimizing the defense cost. Compared to multiple model replacement
strategies, the FMKR provides a faster response to attack behaviors while
consuming less scheduling cost. Based on the feedback from multiple real users
of the Industrial Internet of Things (IIoT) over 2 months, we demonstrate that
the proposed scheme can improve the defense satisfaction rate.
